Bodywork on your Firebird is the most important part of your restoration. For many enthusiast restorers, it’s the most challenging part of restoration and the results are critical to the quality of the overall restoration process. Think of the body as the foundation of your house. If the foundation is not solid, everything else attached to it is compromised.
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The Firebird, or second-generation, F-Body car is a unibody vehicle, and therefore the body is constructed as one unit. The floors, rear frame rails, inner and outer wheelhouses, quarter panels, trunk floor extension panels, rocker panels, rear body panel, roof, and cowl are all welded together to form this one unit. Any of these parts that become compromised due to accident or rust require proper repair procedures to maintain the structural integrity of the body.
These cars have had at least 35 years of ownership and road history. Most of them have lived an interesting life . . . if they could only talk. As most people suspect, and as many experienced owners know, these cars often possess and hide many problems. Many things have happened over the course of these years, and this includes overaggressive use, accidents, and excessive rust. In some cases, routine maintenance has been almost or completely ignored, and this has significant consequences. It means you have more to repair and restore. In addition, some cars may have been improperly stored, and this leads to more rust and mechanical problems.
The importance of bodywork cannot be stressed enough. The overall quality of the restoration is largely determined by bodywork underneath the paint. The quality of the bodywork is evident in this 1970 Formula. The paint has been applied and wet sanded; the results are beautiful. The fender is installed and will be aligned.
Taking all of this into consideration, you need to be well aware that many cars have been repaired, restored, and in some cases messed up over the years. In my experience, the vast majority of repairs are substandard. You need to correct that substandard work while you are at it so the vehicle has a consistent overall look when your restoration is complete.
The doors, trunk lid, and front sheet metal need the unit body to be in proper shape for them to correctly work. Four 15/16-inch bolts hold the front subframe to the underside of the forward portion of the floors and directly under the firewall, which requires the body to be square or it throws off the alignment of the front suspension and sheet metal as well as the engine and transmission.
Safety cannot be compromised. The whole point is for this process to be enjoyable for you and for you to enjoy the car when it is finished. Missing a finger, a limb, becoming visually impaired, partially paralyzed, or dead will not help you enjoy your car. Using the proper safety equipment such as welding gloves, a good-quality auto-darkening welding helmet, safety glasses, and the proper tools to do the particular task are important. Using a dust mask, paint respirator, and well-ventilated areas are also critical to maintaining a safe environment. Make sure you are not welding near open combustibles, as the fumes are what explode, not the liquid. Always use common sense and read the warning labels.
Make sure you clean up properly and allow time to do so before stopping for the day. Never keep working when you’re tired because it is too easy to make a bad call or have an accident when you are tired. Never work under a car without using jack-stands underneath. The coil springs are under immense pressure and can pop out of the control arm and cause major physical harm and death if one loosens. Do not assume that if a mechanic makes a particular procedure look easy that it really is easy.
Don’t wear open-toed shoes; wear steel-reinforced work boots. Wear non-flammable clothing and long-sleeved shirts. Keep your hair out of the way. Make sure you wear gloves, especially when handling flu-ids and chemicals. A majority of the chemicals with which you’ll come in contact will absorb through your skin on contact and can make you very sick very quickly. Make sure you have at least two sufficiently sized Class B fire extinguishers in each end of the workspace.
This chapter discusses the most common rust issues Firebirds have and the proper procedures to deal with rusted areas as well as superficial dents. I do not believe in replacing entire panels unless absolutely necessary. Think of replacing panels as overly invasive surgery. Why cut more than you need? The original sheet metal is unquestionably the best to have, so why remove more metal than you need to?
The bodywork procedures I discuss will make for a proper and long-lasting repair. I cannot emphasize the importance of these steps to ensure a good-quality repair as well as stunning results once your Fire-bird is painted. Prep is paramount when working on the body and the paint reflects that hard work.
After all, the paint job is only a reflection of the level of bodywork and prep performed.
Tools for Bodywork
Performing bodywork is an acquired skill. Although a beginner can learn this skill, body panel replacement techniques and welding are not skills that are learned in a day. That’s why you need to assess and accept what you can reasonably accomplish on your own.
To perform body repair and restoration procedures yourself, you need to rent, borrow, or buy a fair number of specialized tools. You should have a full selection of crimpers, formers, notching tools, an anvil, a bench vise, and metalworking hammers. A basic kit that includes dollies, shot bags, bossing mallets, and hand-held shears costs $200 to $500. Remember, with tools, you get what you pay for; high quality does not come cheap. You can purchase these tools from Snap-on, Sears, Eastwood, Jegs, and a number of automotive supply stores.
Beyond the specialty metalworking hand tools, you need a compressor to run the air flange and punch tool. In addition, you need a MIG welder and a high-quality welder from Lincoln, Hobart, Miller, or another brand; it can cost $900 or more. And of course, when welding, a weldor’s mask and gloves are always essential apparel.
If you’re restoring one car, my recommendation is rent or borrow the tools needed to complete the restoration job. If you plan to restore several cars over the coming years, investing in all the tools necessary to complete more serious restoration jobs is most likely worth it.
Quarter Panel Patch
Firebirds are known to commonly rust behind the rear wheels, especially where the lower portion of the quarter is joined to the trunk extension panel. It is important to evaluate the rusted area and to find where the weakened metal ends and the good metal begins. It is a good idea to cut at least 11⁄2 inches into the solid metal when making a patch. When welding, you need to be sure there is no burn-through because of compromised metal integrity.
Look inside the trunk at the back side of the quarter panels to find any evidence of prior work, such as a line of newer metal indicating where a prior patch may have been made. Also look on the underside of the top of the quarters because larger patch panels generally end at the transition from the side to the top.
Most body shops do not take the time to hide the inside line that is left when doing patch panels, but if you do not see one, that does not mean it has not been patched. It just means that the seam may be hidden or just out of view due to other panels blocking it.
In almost all cases, the three- and four-decade-old 1970–1981 Firebirds need some body panel replacement because after such a long period of time, rust almost inevitably sets in. Bodywork requires metalworking and welding skill; you cannot become proficient overnight. But certainly, these skills can be learned with discipline and practice. In this case, the amount of rust warranted a quarter panel replacement.
1974–1981 Component Removal
Open the trunk lid and remove the two 3/8-inch nuts for the side-marker lights using a socket. Remove the lightbulb socket with a slight twist and pull. The lamp comes out from inside and the lamp bezel comes out from the outside.
Two 7/16-inch nuts hold the spoiler ends. They are located at the top of the quarter panel; remove them from inside the trunk.
Remove the license plate lamp lens. Remove the two Phillips-head screws with a Phillips screwdriver, and twist the bulb retainer, then remove it.
Remove the three taillight bulbs and one reverse lamp bulb by twisting the sockets from inside the trunk. Remove the taillight assembly 7/16-inch nuts (eight total) from inside the trunk. The lamp lens and outer trim are now loose and require some wiggle and twist to remove from the rear body panel. It may be necessary to rotate the top out slightly to allow the lamp to clear the bumper cover.
Next, remove the two 7/16-inch nuts holding each end of the bumper cover to the quarter panel. They are accessible from the underside of the trunk at the quarter panel ends.
Remove the two 11/16-inch bumper bracket nuts, which are accessible from inside the trunk.
Here, the rear bumper, spoiler, and taillight have been removed in preparation for body-work. Firebirds often develop rust around the rear spoiler, particularly if they have not been sealed correctly. In addition, it’s not unusual for Firebirds to rust on the rear body panel or in the trunk.
1970–1973 Component Removal
The 1970–1973 Firebirds were equipped with a chrome rear bumper, smaller taillights, and a fiberglass finish panel, so these components need to be removed. The spoiler and side-marker removal procedures are the same, but taillight and rear bumper steps are slightly different.
Place the jack under the center portion of the rear axle and use it to raise the rear of the car; raise it high enough so the rear tires clear the ground by 4 to 5 inches. Place jack-stands under each end of the rear axle and then lower the floor jack. It is important to have the weight of the car on the suspension and not on the body when replacing panels.
Two additional 11/16-inch nuts for each side sit below and behind the bumper on the rear body panel. Slide the bumper straight back and place the bracket facing down so the cover does not get damaged.
Brackets hold the rear bumper to the vehicle. They are easily accessible from the trunk.
To remove the quarter panel, taillight assembly, finish panel, and related parts, use a 7/16- and 9/16-inch socket and ratchet. Two 9/16-inch bolts hold the outer brackets on the quarter panel side while two 9/16-inch bolts hold the back side outers. A single 9/16-inch bolt holds an inner rear bracket on each side. The taillights are held in with six 7/16-inch nuts on each side: three on the top and three on the bottom. The finish panel also has four 7/16-inch nuts. The license bracket is held in with two 7/16-inch bolts accessible from the outside lower edges. The bracket also holds the finish panel in place. The taillight sockets are held in below the lamp housing. They twist to remove, as do the side-marker lamp sockets. The rear bumper has six brackets attached to it.
You need to reach inside the trunk to remove the bolts that secure the bumper to the car. Like many bolts, these can be very rusty and may require application of a lubricant such as PB Blaster. This rear view of the bare body panel also includes the back side of the rear bumper and its brackets.
Rear Quarter Panel Rust
Remove the wheel-opening molding (if equipped) and eight Phillips- head screws. Cover the exhaust tip extension with a couple of masking tape wraps so it is not damaged while you work in the vicinity.
With a 24-grit wheel, start grinding where you identified the prior patch (as in this case) along the seam. If you could not identify a prior seam, start grinding around the rusted area and work your way out until you see solid metal. You may be grinding through a white powdery substance, which is body filler. Keep grinding through that until you hit metal. Think of this procedure as exploratory surgery.
Check the inside of the trunk and the drop-off areas for any rags or flammable objects before cutting the body to minimize the possibility of a fire. Also make sure the vehicle does not have any fuel leaks. Have a suitably sized Class B fire extinguisher nearby.
Now you can see how thick the body filler is and also where the metal is sound on the remaining panel so you can trim the replacement quarter panel patch to fit once this area is properly prepared. As you can see here, substandard prior repairs have compromised the panel behind the quarter panel. This panel is called a trunk extension or a trunk drop-off. Trunk extensions are extremely rust-prone and may require replacement.
The trunk extension panel is part of the trunk floor. One side attaches to a flange at the floor; the other side ties into the bottom of the quarter panel and also has a flange. The forward portion attaches to the rear of the outer wheelhouse. The rear portion attaches to the rear body panel. This is an important part of the structure of the body. This panel usually rusts behind the quarter panel and is not visible from the inside of the trunk. Therefore, it is commonly overlooked.
A trunk extension replacement quarter panel patch is not of great quality and often needs some minor reworking to make it fit and function as original. Having access to a shrinker and stretcher is helpful. This is a difficult skill to master. If you do not have access to a shrinker and stretcher, you can use a hammer and dolly to get the shape you need once the panel is installed.
Most sheet metal for patch panels is 16-gauge, but the thickness can vary depending on the manufacturer. These patches are generally available for about $50. Using the stretcher part of the tool is a matter of inserting the panel and working the metal with the handle to stretch the metal.
The same goes for the shrinker to make the curve that you need. It takes multiple times to place the panel on the body panel to com-pare your progress. Small steps are necessary because you really do not want to go too far too fast with this procedure.
The procedure works by trial and error. Starting out with just some scrap sheet metal gives you the feel and technique necessary to figure out how the tools work. Practice will make you much more proficient.
Place the patch panel in the proper position. Use body clamps to clamp it down, and make sure all mating surfaces are flush. Body clamps are available in small, medium, and large sizes and you should purchase an assortment. Almost any tool supplier (Eastwood, Sears) carries them. Make sure you have at least 10 clamps because every panel will use a different number of clamps to hold it.
Whenever you are mating a replacement panel to an existing panel, you must have enough clamps to hold the panel in place correctly to allow for proper welding. Once you have welded in the patch, be sure to look at the panel from all angles and adjust your clamps as necessary until you are satisfied that you have the panel sitting in the right place. You can obtain the anti-heat compound from many sources, including Eastwood.
Trunk Extension Patch Panel Installation
Step 1: Evaluate Patch Panel
Measure and trim the patch panel. It is important to make sure you do not cut off too much metal. Use a marker to draw a line to follow with the cut-off wheel.
Step 2: Cut Quarter Panel
Many second-generation F-Body cars no longer have solid sheet metal below the paint on the rear quarter panels, and rust may be poking through. This 1978 Firebird had a lot of body filler; I had to cut through it to find solid metal all the way around. I had previously tested the area with a magnet and knew I had a lot of filler to deal with. Simply rapping your knuckles on the panel tells you if it has a lot of filler. When you rap the panel and hear a thud sound instead flying metal shards. Also make sure that no flammable fluids or rags are in the general vicinity. Once you start the tool, slowly lower it into the metal and smoothly push the tool along the line. Use a cut-off wheel on a pneumatic rotary tool to make the first cut. It should be about 2 inches below where you designate the final cut across the top of the sheet metal. Remember, if you remove too much sheet metal you may need to replace the entire panel.
Step 3: Mark Your Second Cut Line
Once again, measure several times and make sure your lines are accurate. It is better to cut smaller sizes later than to cut too much now. You can mark this cut line with a magic marker or you can simply drag a flat-blade screwdriver across the metal so you can see a line in the e-coat. A good solid line is important to use as a guide when you cut the metal with your cutoff tool. Make sure the metal is clear underneath so you do not accidentally cut something you did not intend to. Another tip is to place a strip of masking tape along the line you have drawn to give you a better visual as you cut.
Step 4: Cut Other Sides of Panel
Cut the other two sides of the panel and peel back the panel. The technique is the same to cut the sides of the panel. You just want to be sure not to cut the metal underneath it.
Step 5: Scrape Off Seam Sealer
Use a scraper or utility knife to remove the thick seam sealer that hides the seam between the trunk floorpan and the extension. Once you get under the sealer, you can peel it off.
Step 6: Cut Quarter Panel Seam
Use the cutoff wheel and make a small cut at the metal seam where the extension and floor meet. Use an air saw to cut along that seam. The air saw cut only needs to be about 2 inches long to allow the cutoff tool wheel to smoothly engage the line. If you did not make an initial cut with an air saw, your cutting tool could move back and forth before actually making a cut. That may result in the cut being in the wrong place.
Step 7: Remove Quarter Panel
Cut off the rest of the panel where it meets the rear body panel and wheel-house. Remove the quarter panel and extension. This panel had serious issues and the seam line of the prior patch is now visible.
Step 8: Trim Metal in Quarter Panel Area
With the cutoff wheel trim the rest of the remaining metal edges to reveal the flanges. Remove the spot weld fragments to provide a smooth surface to attach the new trunk extension panel. It may also be necessary to use tin snips, hammer, and chisel to remove the remnants.
Step 9: Remove Excess Sheet Metal
Now that all spot welds and excess metal have been removed, you have a flush surface for attaching the new trunk extension panel. It can be fitted against the edge to verify that the two flanges are flush. Simply using a hammer and dolly on the metal edge to straighten the flange makes the two panels mate together. The rusted panel below the taillights is also being replaced.
Step 10: Check Fitment of Panel Patch
Check the fitment of the new extension against the floor, wheelhouse, and rear body panel. You must straighten the flanges as necessary to ensure a flush fitment. It is not uncommon for the metal to have distorted somewhat during the remnant removal process. The edges of the new panel need to be checked, because it is common for the edges to distort during manufacturing or shipping.You want to make sure every mating surface matches up squarely for a proper fit. This is accomplished by constantly checking and re-checking every edge of the existing panel and the new panel to make sure the flanges are going to fit flush. When you correct one side, double-check the other side; modifying one side can slightly change the other. This has to be done over and over again until the part fits perfectly. Leaving gaps can, at a minimum, cause leaks or debris to get in or worse, cause an adjacent panel to not fit correctly.
Step 11: Clamp Panel in Place
Test fit the panel and use body clamps to hold it in place. It should fit flush against all flanges. Be sure that all the mating surfaces fit flush against the existing panel as you clamp them into place. This is how the panel will sit after you have welded it. This is not a step to take lightly and should be checked multiple times until you are satisfied with the fitment.
Step 12: Punch Spot Weld Holes
Once you have verified that the panel fitment is good as described previously, remove the panel. Use an air flange/punch tool (available for less than $75) to punch holes in the new panel flanges about 1 inch apart. These holes provide an opening for the spot welds to join to the panel. Take your time and punch the holes in the middle of the flange so the work is clean and professional. This trunk extension is part of the body structure so it should have many spot welds to hold it in place and provide strength.
Step 13: Strip Paint off Panels
Use a wire wheel to clean up the edges of both panels (new and original joining) until they are shiny bright metal. This ensures a clean surface. Use a good-quality weld-through primer, such as 3M Weld-Thru Primer (PN 0511 31-05917). This reduces spatter and distortion caused by excessive heat that occurs during the welding process and replaces certain properties in the metal that are burned off. Spray some weld-through primer on all surfaces that will be welded. A few light coats are sufficient. Let the panel sit 5 minutes between coats and approximately 10 minutes after the final coat.
Step 14: Install Trunk Extension Panel
Clamp the panel into place. Use as many clamps as needed to properly hold the panel in place but still allow enough space to properly weld it. It is critical to fit this panel precisely. The quarter panel attaches to it and any mistake could make the quarter panel look distorted.
Step 15: Tack Weld Trunk Extension
Using a good-quality MIG welder perform some test welds on scrap sheet metal to determine the settings to achieve a good weld. Burning a hole in the metal means that the setting is too hot. Lots of spattering can mean that the setting is too cold or that contaminants are on the panel. Every welder requires a different setting depending on its level of power and what material you are welding. Starting the welding at the farthest points and working inward prevents the panel from warping or distorting from heat. This is the same procedure to be used when welding on other panels where you are not plug welding but rather stitch, butt, or tack welding.
Step 16: Inspect Tack Welds
Take a good look at your tackwelds before you continue because you want to be sure the welder settings are correct and you’re not transferring too much heat to the weld area. An excellent plug weld should look like this on both sides.
Step 17: Adjust Patch Panel Radius
A shrinker/stretcher tool lets you easily fabricate gentle radius bends and contours. These tools generally sell for less than $200 at most restoration supply stores. The technique for shrinking and stretching metal takes time and practice. Perform some tests on scrap metal to practice making the metal bend the way you need it to bend. Wear leather gloves at all times. Secure the tool to a workbench. The better the tool is secured, the easier it is to use. Pre-drill and tap two holes into the base; it accepts 3/8-inch bolts. Bend the metal to be formed 90 degrees on a corner or a brake, if you have one. Create a flange that is no longer than 2 inches. Make a template out of cardboard. Trace the outline of the section you want to form. Work the leading edge first. This reduces the resistance and allows for easy and accurate working of the metal.
For best results, place the metal halfway into the jaws. Any metal that rises can be hammered out. Control the amount of pressure you exert on the handle and the number of strokes used while forming the metal. Move the metal back and forth until the desired radius is obtained. The jaws of the tool are ser-rated to bite into the metal. These serrations leave marks, which can easily be smoothed with a grinder or sander. Instructional videos on the Internet can help you gain skill.
Step 18: Form Correct Radius
The replacement quarter patch does not have the slight con-cave roll in the lower portion, as does the stock panel. Although the roll may be slight, you need this roll for an accurate and faithful body profile. Using the shrinker/stretcher technique helps makes the slight bend necessary to achieve the correct body profile.
Step 19: Use Factory Wheel Opening Molding for Reference
It is a good idea to use the factory wheel opening molding (if equipped) as a guide for the proper bend.
Step 20: Create Flange on Quarter Panel
You need to create a recessed flange on the quarter panel so the patch panel can overlap the quarter panel and anchor it to the car. An air punch/flange tool is very easy to operate. Simply place the jaws of the tool on the edge of the existing quarter panel until it stops. Then press the button, and the flange is made. The jaws of the tool are fixed so you always get the same size of flange.
Step 21: Create Flange on Quarter Panel (CONTINUED)
Carefully guide the air flange tool across the length of the quarter panel so you create one even flange surface area. Simply keep moving the flange tool over to the next spot after you have made the flange in that area until the entire area you want to flange is completed. You are now ready to final fit the patch panel.
Step 22: Cut Patch Panel
In this photo, our veteran body technician trims the panel on a parts cart. I recommend using a workbench that affords you plenty of room. Make sure the patch panel is clamped or firmly held down on the bench. Position yourself so you have a clear sight line to the tape because you want the cut to be as straight as possible. Start from one end and methodically move the rotary across the trim panel until the cut is complete. The procedure is described in Step 3.
Step 23: Prime Patch Panel
Treat the panel with a weld-through primer. The 3M product’s quality is second to none and I always get consistent results. Place the panel over some newspaper or a spray cloth and evenly coat all the edges of the patch panel that will be welded. I typically apply two coats for thorough coverage. After the primer has been applied, use an air punch/flange tool to place spot weld holes 1 to 1.5 inches away from the edge and spaced 1 to 1.5 inches apart. These holes align with the flange area on the quarter panel and the spot welds hold the panel in place.
Step 24: Tack Weld Patch Panel
Properly fit the patch panel in place using body clamps. Drill holes into the adjoining panel for spot welds Tack weld the panel starting at the corners. This is the same procedure used on fenders.
Rear Body Panel Sectioning
You need to section the rear body panel if the lower half has been previously rotted and poorly repaired. The upper half may be in good condition and structurally sound. Remember, you do not have to replace an entire panel just because you purchased it. This is especially true with structural panels. On this project, I was able to remove the lower section below the frame rail attachment point and leave the body structurally intact. This makes for a better repair.
Sometimes the entire panel may need replacement. Every car rusts differently depending on its care (or lack of care) and the environments to which it has been exposed over its lifetime.
I will section the panel just below the spot welds where the rear body panel ties into the trunk floor. This process is not exceptionally difficult, but it requires exact measurements and concentration.
You want to ensure that the part of the panel that remains on the car is solid. You should cut at least 1/2 to 1 inch beyond the edge of the corroded or rusted metal, so the panel serves as a solid foundation for the patch panel. Multiple measurements are critical so a proper cut is made. In the body Industry, this is called sectioning, and it means you are only replacing a portion of the panel and not the entire panel.
When trimming a wide panel, leave a strip of metal toward the center to help assist with placing the panel. Once you have the panel where you want it, use a cutting wheel to lightly cut a groove into the new panel and existing panel to create alignment marks. This allows you to take the panel on and off for final trim but still line it up properly.
Tail Panel Installation
Step 1: Inspect Trunk and Valance Area
The lower portion of a rear body panel is a common area for Firebirds to rust. The 1974 and later Firebirds tend to have more rust in this area because the sheet metal is hidden behind the rear bumper cover and moisture gets trapped behind the bumper cover. Often that area is not cleaned because it’s not visible.
Step 2: Determine Cut Line on Valance
This cut panel reveals prior body filler and rust. After determining where the solid metal starts, use a cutoff wheel to cut along your marked line to properly section the panel. You need to find clean, non-corroded metal so you can cut at least 1.5 inches into that solid metal surface.
Step 3: Remove Rust from Valance
It’s important to remove all the rusted sheet metal from an area; once metal has started rusting it doesn’t stop until it’s cut out and replaced with fresh sheet metal. You can use a cold chisel or screwdriver to knock off the rusted metal; a chisel often works the best. A hammer and chisel are typically required for tougher spots.
Step 4: Inspect New Sheet-Metal Panel
Here is the new replacement panel prior to being sectioned. It is important to measure multiple times before cutting the replacement panel. Several suppliers offer this rear body panel, including Tamraz Parts Warehouse (I bought one for $288, including shipping). If you trim the panel a bit longer it can incrementally be trimmed until a perfect fit is made rather than trying to add metal to fill the gaps.
Step 5: Apply Rust Neutralizer
Once you have removed the panel, cleanup is needed. Use a rust neutralizer such as Mar-Hyde One-Step (PN 3509). It converts the rust into a black primer sealer.
Step 6: Neutralize Rust
Apply rust neutralizer to the exposed metal on the original side and the back side of the new panel to help minimize corrosion.
Step 7: Punch Spot Weld Holes in Rear Valance
Use an air punch tool for adding holes on the bottom and sides approximately 1 to 1.5 inches apart. Be sure to place the holes in the center of the flange for a neat and clean appearance but also so the panel has the best support and strength when attached. Find a large clean area of your shop to spray down the valance with weld-through primer. Apply the anti-heat compound to the existing part of the taillight panel (as you did when repairing fenders). Using the anti-heat compound reduces the possibility of warping the tail panel while welding.
Step 8: Clamp Patch Panel in Place
Start clamping the panel in place and trim the edges as needed to make them fit as close to the original panel as possible. Make sure that the new valance is correctly aligned with the existing panel. Once it’s tack welded in place, you would have to cut off or grind down the tack welds to realign it. Again, place the spot weld punch holes 1 to 1.5 inches apart. Use the body clamps as needed to hold the panel in place but allow enough room for welding.
Step 9: Butt Weld Seams
Align the new lower body panel with the existing upper body panel. Tack weld a couple of corners along with the existing ear. Press along the line where the new panel meets the old to make sure there is no overlap. Here, I butt weld the two panels together. You want the seam to fit as flush as possible so you have less metal work to do and use less body filler later. You cannot plug weld the panel because there isn’t a flange. You need to trim the panel in the middle. Make sure the MIG welder is set at the proper amp setting and the correct wire is being used. Make the actual welds start at the farthest point and work inward. Once enough of the panel has been welded the ear can be simply cut off.
Step 10: Tack Weld Patch Panel
Tack weld on the outside of the panel and work your way to the center. Keep the body clamps in place until you have spot welded in the center of the panel. You do not want the panel to shift during this process. Place about a dozen spot welds at the outside of the panel on each side.
Step11: Tack Weld Patch Panel (CONTINUED)
Remove the center ear that was used to anchor the lower panel to the upper panel. Place spot welds every 8 inches along the seam between the upper and lower valance panels (the panel is now securely welded in place). Remove the body clamps. When all the spot welds have been placed along the panel seam, start stitch welding between those seams. It’s like connecting the dots. This thin-gauge sheet metal can withstand a moderate amount of heat before it starts warping, and warpage must be avoided. Lay down a bead of weld between two spot welds and then move to the opposite end of the panel so you are spreading the heat. Apply air to the area of the panel that has been stitch welded and let it cool for a few minutes. This is the best way to avoiding warping the panels.
Step 12: Smooth Out Welds
After the panel has cooled grind the welds smooth to finalize the metal work. A coarse 36-grit grinding disc on a DA sander is sufficient to remove the weld slag.
Patch Panel Fabrication
Sometimes you need to patch a small area on a panel, and it is not feasible to buy an entire panel just to cut a small piece out of it, nor is there a replacement patch panel available. You need good tin snips, a vise, a hammer, a marker, and 16-gauge sheet metal of sufficient size for the panel you intend to make. You also need something to form the metal
against. For this project, I used a wheel-bearing race to create the correct radius for a patch panel. As long as you have something the same size of the radius of the curve you need, you will be fine. You need patience to make the panel, especially when forming the radius.
I ran into this very problem with a 1978 Firebird Formula W72 car. I had replaced the lower quarter panel with a patch panel, but that panel did not cover a particular area that required a patch. This was the edge of the quarter where the bumper resided below it and the taillight was just on the inner side of it. This area commonly rusts because the rear spoiler ends either have their sealant dry out or someone doesn’t properly replace the sealer when reinstalling the spoiler end. It also can be due to the trunk lid leaking from a failed and misadjusted weatherstrip on the trunk lid.
Patch Panel Installation
Step 1: Inspect Quarter Panel
Here, the rear edge of the quarter panel near the front fascia has rusted through. As you can see, someone has already attempted a partial patch in this area but the new patch panel did not cover this area. Patch panel fabrication is easiest when you have something to copy, as in this case. You can use 18-gauge sheet metal to fabricate a patch panel for this area. To complete this procedure, use a vise, cutting shears, and metal-working hammer.
Step 2: Cut Sheet-Metal Patch
Use metal shears to cut a piece of sheet metal large enough to serve as a patch panel for the curved areas. A large patch panel is required for the curved profile of the quarter panel. And the patch panel needs to be stretched to fit this area. Compare the size of the new sheet metal to the actual work area to ensure the piece is large enough.
Step3: Mark Sheet-Metal Patch
Place a sheet-metal patch on the side of the quarter panel and, with a Sharpie or other permanent marker, draw a solid line where you intend to cut. Use dotted lines for where you will be bending the metal.
Step 4: Trim Sheet-Metal Patch
<Because you are cutting such a small piece of 18-gauge sheet metal, you do not need air-powered shears. Use tip snips to trim along the traced line, but be careful not to trim off too much material.
Step 5: Create Sheet-Metal Radius and Flange
To form the piece of sheet metal into a patch panel worthy of installation, you need a ball-peen hammer, vice, and dolly. If you bought a fairly complete metal forming tool kit, a dolly should be included. If not, you need to buy a dolly of the correct radius. Here, this wheel-bearing race was the ideal size for the radius on the panel, and it came from a front rotor wheel-bearing race on another Trans Am. You use it to help shape the panel. The wheel-bearing race is basically being used as a dolly.
Place the sheet metal and the wheel-bearing race into a vise so the lines are in the correct position. Stretching and forming sheet metal requires many small moves until the flat steel is correctly formed into the piece that can be welded onto the car. Strike the sheet metal with the ball end of a hammer repeatedly within the race. Slowly move and stretch the metal to form along the lines drawn. Moderate blows around the race area helps shape the metal slowly to make the curve you need. Take your time.
Once the curve has been made, check it against the body for fitment. You butt weld this piece onto the quarter panel (much the same as with the rear body panel). Trim and fit the panel as it gets closer to its final shape.
Place the patch panel in the vice along the second bend line. Place it back in vise once the panel fits properly to the quarter. (Here, the bearing race is used to form the radius of the patch panel.) Use a your metal working hammer to first form the radius. As you can see the radius does not extend beyond the bodyline. The metal around the radius has been worked so it’s at about a 90-degree angle.
Step 9: Create Sheet-Metal Radius and Flange (CONTINUED)
It may require multiple trips from the car to the vise to achieve proper fit. Be sure the patch panel is held in the vice at the bend line. Once you have established the radius curve, use the hammer to work the metal and stretch it to the top of the vice. The leading edge of the metal patch panel should align with the radius and form a 90-degree bend.
Step 10: Test Fit Patch Panel
Be sure that the patch panel follows the contour of the quarter panel and properly aligns with the bumper. A properly fabricated patch requires much less body filler and makes for a much better repair. Often you need to compare the patch panel to the area and use tin snips or shears to trim it. Be patient. Don’t take too much metal off at once or you will need to start over.
Step 11: Test Fit Patch Panel
You always want the patch panel to align with adjacent panels or parts. When the car is completely assembled, the panel gap should be straight and a consistent 1/8 inch thick. It’s very important to check the patch at this stage of the process. On this car, the rear bumper cover also resides in this area so the cover was also checked for proper radius.
Step 12: Mark Cut Lines on Quarter Panel
Once you’ve verified that the patch fits correctly and properly follows the body curve, it is time to prepare the body to accept the patch. Use the metal patch panel as a template for the cut on the quarter panel. Hold the patch panel in place and outline the profile against the quarter panel. You’re now ready to use a cutoff wheel to remove the damaged sheet metal. It is very important to check every angle, curve, and contour to make sure the patch fits into the panel. Think of this as making a replacement piece for a jigsaw puzzle. Draw an outline on the body to prepare to cut the body for the patch. Draw the outline above the contour, and make the cut on the outside of the line so you can fine-tune the trim later.
Step 13: Cut Rusted Metal from Quarter Panel
Using the cutting wheel, cut a horizontal line just below the top line by about an inch and along the other two lines to remove the panel. Once the cuts are made, grab the small metal panel with pliers and bend it down. This may reveal more hidden corrosion, such as from a leaking spoiler end.
Step 14: Remove Rust and Apply Rust Neutralizer
Use a wire brush or an 80-grit sanding wheel to remove surface rust, loose particles, and debris on the metal. Then apply a rust converter to neutralize the rust. Once the rust converter has dried, use a hammer to work the metal on the contour into a flange. Like other metal forming, you need to make a number of small moves so don’t rush it. Spray some weld-through primer around the areas to be welded and inside the trunk area you just cleaned. This existing panel is only partially flanged.
Step 15: Punch Tack Weld Holes and Prime
Punch the spot weld holes into the patch panel and spray the patch panel with primer. Punch holes only in the panel where it is being fitted, not on the other end. The whole point of the punched holes is to allow the spot welds to fill the hole and attach to the panel receiving the patch. This finished patch has the plug weld holes punched.
Step 16: Fit Patch Panel on Quarter Panel
Re-install the bumper to check the fitment of the patch; this is a complex patch and the fit is critical. Properly align the patch in the quarter panel and make sure it accurately follows the contour of the bumper and the spacing remains consistent. Because this panel is so small and the area being patched is not very accessible you hold the patch in place and apply tack welds to the corners.
Step 17: Tack Weld Patch Panel
Fit the patch and use a little pressure from a screwdriver to adjust the panel to get the patch to fit better. When you have established the correct alignment, place a quick tack weld in the patch panel’s corner to hold it in place.
Step 18: Tack Weld Patch Panel (CONTINUED)
A tack weld in the corner holds the patch in place but pivots enough to allow further adjustments. This patch panel has been adjusted upward and there is a slight gap at the bottom, but a gap this small presents no problem. A bead of weld fills it in and can be ground down. After you are finished with the adjustments, remove the bumper and weld the panel.
Step 19: Stitch Weld Patch Panel
Stitch weld between all the tack welds so the panel is completely welded in place. This is a methodical process and you cannot weld the panel too quickly. Stitch weld between two spot welds on one side of the panel and quench with air. Let two or three minutes pass. Move to the opposite end of the panel and stitch weld between the two spot welds. And then again, use air to quench the bead. Then continue alternating until the entire panel is welded. Once the welding has been completed, allow the panel to cool for 30 minutes or so. By that time, the welding heat should be completely dissipated. At this time, the panel should be cool; now you can grind them smooth. Once you are finished, your result should look sort of like this. It almost looks as though nothing was ever done!
Almost all Firebird second- generation fenders interchange among years. Although the earlier- and later-year fenders have some cosmetic differences that are not readily apparent, they do not affect the fit and function. The fenders can be found used or as reproductions.
The only important differences are at the front leading edge. Pontiac used two different brackets between 1970–1975 and 1976–1981 to pro-vide mounting for the front lower valance on the earlier Firebirds and the bumper cover on the later years. These brackets are tack welded on at the front of the fender edge and easily removed with a small cutting wheel. Simply fit them onto the front of the fenders, clamp them in place, and tack weld them on.
This means that you can purchase a later fender to use on an earlier Firebird. This is especially helpful given the rarity of original or good used fenders because you now have an 11-year run of Firebirds to pick from. If you happen to locate an earlier fender and need to use it on a later Firebird, you can do that also.
This is a 1978 driver-side original Firebird fender with the later front bracket. The front bumper cover can be mounted at the upper portion of the bracket.
This is the 1978 passenger-side fender that you spot welded the early bracket onto after removing the front bracket. The contours fit perfectly. The bracket has provisions for the lower valance; the 1975 and earlier models have the same bracket.
Bear in mind that all Firebird, Firebird Esprit, and Formula fenders interchange with the exception of the 1971 fenders. Pontiac had a fake small vent placed above the Firebird name-plate on each fender in 1971. If you happen to find 1971 Firebird fenders, that vent opening can be closed off.
Trans Am fenders have a single air extractor opening in the side of the fender. All Trans Am years inter-change, including the 1971, as they were not different.
Fender Patch Preparation
Firebird fenders commonly rust just behind the front wheel near the attachment bolts on the underside. If your fender doesn’t require replacement, but has some damage or rust, you can repair or patch it. A fender repair patch is available through Internet sources or The Parts Place.
The patch is not very good quality as far as the shape of it, but it is of sufficient gauge to use as a last resort or for a good patch.
The procedure and technique for installing the patch can be per-formed with the fender installed. However, I recommend removing the fender to make for a better repair and to be able to treat the back side so the panel does not rust from the back side. The ears on the bottom of the fender where the attaching bolts are located also are prone to rust. The replacement patch panel also has the attachment ears.
Step 1: Remove Front Fender
It’s complicated to remove the front fenders on the Firebird because it has hidden bolts and other panels that tie into the fender. Rust commonly forms at the lower portion of the fender behind the front wheel. However, this particular 1978 Formula W72 in Martinique Blue has sustained an impact, which was not repaired properly. Although this is collision damage, the repair approach is the same as if the area were rusted.
Step 2: Remove Headlamp Plugs
Open the hood and look between the bumper cover and the core support; you see the head-lamp plugs. Reach down and separate the plugs from the headlamps. You also see the lower retainer bracket 1/2-inch bolt on each side behind the headlamps; it needs to be removed. Use a socket and ratchet and an extension to remove the bolts.
Step 3: Hood Latch Support
From underneath the car, reach up and twist out the parking lamp sockets and let them dangle. Two upper 1/2-inch nuts and two lower 1/2-inch bolts on each side secure the front cover to the fenders. Remove the two 1/2-inch bolts that attach the center bumper brace to the hood latch support.
Step 4: Remove Upper Cover Brackets to Radiator Support
Remove the 1/2-inch bolts (one on each side) that hold the upper retainer on top of the radiator support.
Step 5: Remove Front Bumper Braces
Remove the four 11/16-inch nuts on each side that attach the front bumper reinforcement to the braces. Remove the hood latch release handle bracket located on the driver’s side of the bumper reinforcement; it is held in with a 1/2-inch bolt. Slide the front bumper cover assembly forward and place it in a safe place.
Step 6: Measure Fender-to-Fender Distance
This Formula fender measurement is 54.75 inches in the front.
Step 7: Measure Fender (CONTINUED)
The fender measurement is 57.50 inches at the rear using the base of the wipers and hood stops as points of reference.
Step 8: Disconnect Washer Hose Line
Disconnect the main washer hose line to the nozzle tee on the hood. Remove the hood hinge 9/16-inch bolts (two per side).
Step 9: Remove Hood
The hood is heavy and cumbersome; it can slide down and break the windshield or fall off and hurt some-one if you attempt to remove it by yourself. Get a friend to help you. You need to be ready to catch and safely move the hood when the bolts have been removed. First, remove the two forward bolts and then place your shoulder underneath the hood and a hand on the backside to support the hood. Use a socket and ratchet to remove the rear two bolts to free the hood from the hinges. If you’re positioned under the hood as described, you should have a firm grasp. Once removed, move it to a storage space to avoid damaging it.
You must remove all smaller parts that affect correct fender removal. Pontiac was in the middle of changing from SAE nuts and bolts to metric during the year this Formula was built so you may find a mix of metric and SAE, all SAE, or all metric depending on when your particular Firebird was built. In my experience, 1976 and older Firebirds were all SAE, 1977–1979 were a mix, and later models were also a mix but more heavily metric.
Raise the vehicle and place jack-stands under the front lower control arms so the body is supported by the suspension. Given the weakness of the subframe and having only four bolts attached to the unit body, it is not unusual to have the front sheet-metal flex when it’s not supported by the suspension.
I remove the passenger-side fender in this example. The driver-side fender is not much different, except for some ancillary items attached to the wheelhouse.
Step 1: Remove Radiator Overflow Bottle
Use a ratchet and socket to remove the two 10-mm bolts that hold the radiator overflow bottle to the wheelhouse.
Step 2: Remove Wheelhouse Bolts
Use a socket and ratchet to remove the two upper inner- wheelhouse 1/2-inch bolts and the two upper support-bar 1/2-inch bolts.
Step 3: Remove Side-Marker Lamp
Remove the side-marker lamp socket by twisting and pulling the bulb out.
Step 4: Remove Wheelhouse Bolts
Remove the two 1/2-inch rear wheelhouse support bolts. The wheelhouse may require a bit of wresting to remove it. It does not fall down when the bolts are removed.
Step 5: Remove Support Panel
Once again, socket and ratchet are the preferred tools to remove the three 1/2-inch bolts that secure the small front wheelhouse filler panel to the radiator support panel.
Step 6: Remove Fender Hardware
Remove the two lower forward 1/2-inch bolts that attach to the lower tie-bar of the radiator support.
Step 7: Remove Fender Hardware(CONTINUED)
Remove the five 1/2-inch bolts that secure the fender to the wheelhouse, which are located around the wheel opening.
Step 8 :
Remove one 9/16-inch bolt in upper rear of fender (located in the door opening).
Use a 9/16-inch socket and ratchet to remove two 9/16- and one 1/2-inch lower bolts behind the front wheel.
Use a 9/16-inch socket and ratchet to remove the 9/16-inch bolt on top of the fender, at the cowl by the windshield.
Remove two 1/2-inch bolts where the fender and the radiator support meet.
Locate the 9/16-inch bolt at the firewall where the back of the hood hinge is located.
Step 13: Remove Fender Hardware CONTINUED
Use a 6-inch extension and deep well socket to remove this bolt.
Step 14: Remove Fender
Because the bolts no longer 14 Because the bolts no longer secure the fender it can be separated from the chassis and other bodywork. After years of attachment to the car, it probably requires some wiggling to slide it off. Be careful when you wiggle the fender, and watch the top ear of the fender because you don’t want to hit the windshield and crack it. The wheelhouse is loose.
In this example, a smaller dent was filled without any attempt to pull it out. I will not be able to hammer and dolly that dent because it is located in front of the stiffener brace. I will use the Uni-Spotter, also known as a stud gun. The technique is quite simple.
The stud needs to be placed in the center of the dent. It may be necessary to attach additional studs around the circumference of the dent. Larger dents require the studs to be placed all around the dent. Each stud pulls on the dent as you work toward the center of the dent.
The stud gun is a tool used when access to the back of the dent is not possible. Before this invention, the common method was to drill a hole or a series of holes in the center and all around the dent. A screw was threaded in and a slide hammer attached. The slide portion of the hammer slid back with force to pull back the dent. The problem was that the area where the screw was threaded frequently created more damage and required additional labor to repair.
The Uni-Spotter works on the same principle but does not create additional damage or labor. The cost of a Uni-Spotter may be prohibitive, but your local rental shop may have one.
Using a Uni-Spotter is the proper way to repair a dent when you cannot access the back side of the panel. A small dent like this did not require the major amount of labor needed to remove and reinstall the fender to properly repair the dent.
Step 1: Remove Body Filler
Use an abrasive paint-stripping disc to remove the paint. 3M offers a wide range of discs, such as the SandBlaster series, to quickly and safely remove the paint and underlying body filler. The 80-grit abrasive discs are often used to strip away the body filler. Once you work through the paint, the amount of body filler is revealed. Here it was quite substantial. Work the rotating disc back and fourth using moderate pressure and evenly strip the filler from the panel. Be careful not to grind one area for too long or the panel will warp.
Step 2: Cut Out Dent in Fender
Use a straight edge and a Sharpie to precisely mark the cut-out line on the fender. Once the line has been drawn, use a pneumatic rotary tool with a 3-inch 80-grit wheel to cut out the affected area.
Step 3: Cut Out Dent in Fender
The damaged area has been completely removed.
Step 4: Inspect Removed Panel
The lower part of this fender was in poor shape. The removed metal had a large amount of body filler in it so it was necessary to remove it.
Step 5: Remove Paint
I used a 6-inch DA sander with 80-grit sandpaper to remove the paint and, in this case, the body filler. Use an orbital sander and apply even pressure as you work through the layers of paint.
Step 6: Inspect Stripped Body Panel
Even after the entire half of the body panel has been stripped and the body filler has been removed, the panel still needs a lot of work. A dent needs to be pulled out and another part of the panel needs straightening. Even though I am going to cover the metalworking process and I am going to show how to use hammers, dollies, and dies, you should have a basic metal-working kit at your disposal. In addition, Automotive Sheet Metal Forming & Fabrication by Matt Joseph is a good resource for learning how to rework metal.
Step 7: Weld Dent Rod to Panel
Insert a welding stud into a Uni-Spotter. Place the stud on the area of the dent you want to pull. Ensure the grounding element is flush against the panel and pull the trigger. There will be a glow when proper contact is made. The trigger only needs to be pressed for a second or two.
Step 8: Weld Dent Rod to Panel
If the rod is firmly attached to the sheet metal, you can see the heat-affected zone. If the dent is larger, you many need to weld several dent rods to the dented area so you can pull iAt out evenly.
Step 9: Insert Slide Hammer
Place the slide hammer over the stud.
Step 10: Pull Dent Out
Glide the hammer up the shaft until it reaches the stop at the end. When it reaches the end, this force pulls the dent out of the panel. You can adjust the amount of force depending on the size of the dent. With a smaller dent, apply moderate force when sliding the hammer. Larger dents require more slide force. Slide the hammer back and forth until dent is pulled. Carefully examine the dented area to be sure the sheet metal in the dent aligns with the rest of panel. You may need to use several studs for larger dents, but the technique is the same.
Step 11: Cut Off Rod Stud
Use a wire cutter to simply cut off the stud just above its base.
Step 12: Grind off Weld Bubble
The base, or weld bubble, remaining on the fender needs to be ground off. Use an orbital sander with 80-grit paper.
After grinding off the weld, you should see no evidence of the rod or the dent.
Fender Patch Installation
The patch for the fender is cut from the panel I purchased and fit-ted into the opening. The procedure is the same as for rear body panel repairs.
As with other patch-welding projects, you butt weld the patch panel into the fender. To do so you need to correctly align the panel, place tack welds on each corner, and then place several more tack welds on the sheet metal. After the tack welds have been placed on the panel, weld the entire seam of the panel by stitch welding between the tack welds.
Stitch weld on one side of the panel, switch to the other side; continue alternating between sides to spread the heat around. You need to manage the welding heat to prevent warping the panel and creating other problems. You should place anti-heat compound on either side of the welding area on the sheet metal. You can also quench the weld with air to mitigate heat transfer. The compound helps prevent the 18-gauge sheet metal from warping the surrounding metal as it absorbs the heat.
When the entire patch panel has been stitch welded, remove the anti-heat com-pound. Use an 80-grit wheel on a rotary tool to grind the bead and make the joined panels flush. Once again, take your time when you do this. An abrasive wheel generates heat as it removes material so you don’t want to warp the panel or take off too much metal.
1970–1973 Front End Removal
The 1970–1973 front end removal procedures are a bit different than the 1974–1981 models. Following is a brief overview.
Step 1: Remove Front Endura Bumper
The front Endura bumper is not bolted to the fenders. Instead two 3/4-inch nuts on each side hold it to a pair of bumper braces that bolt to the frame rail. The braces curve upward and the front bumper attaches with one 11/16-inch nut and bolt at the top and another 11/16-inch nut and bolt at the lower portion of the bumper.
Step 2: Remove Front Endura Bumper (CONTINUED)
The upper portion of the bumper is attached (with bushings) to the radiator support. To remove the bumper, use an open-end wrench and a socket/ratchet tool.
The 1970–1972 bumpers do not have the support structure of this 1973 model because the 1973 models had to pass new front crash standards for a 5-mph impact. Pontiac installed this support structure behind the new bumper so the Firebirds passed the crash standard. Although the bumpers appeared to be the same as the previous year, they were not. In addition, the grilles are set deeper. This is the first telltale sign of a 1973 Firebird.
The lower valance panel holds the two front park lamps with a chrome trim in the front. Remove the two Phillips-head screws on each side that retain the chrome trim. The parking lamp housing is also held in with the same screws.
Six 1/2-inch bolts on the bottom and three 1/2-inch bolts at the front hold the lower valance. One bolt is behind each park lamp, and the center bolt is visible unless a front license plate bracket is installed.
Although it is possible to remove the radiator support without removing the other fender, I recommend removing it as the reinstallation does not allow the fender to be on. Now you can go back to the radiator support removal, which is similar for all model years.
Engine Accessories and Related Component Removal
Step 1: Remove Side-Marker Light
Remove the side-marker light 10-mm ground bolt located on each back side of the support.
Step 2: Remove Plastic Retainers
Remove the seven wire harness plastic retainers, allowing the wire harness to fall out. This can easily be done with a flat-blade screwdriver.
Step 3: Remove Wiring Harness and Battery
“Unthread” the wiring harness from the passenttps://cdn.shopify.com/s/files/1/0367/8791/2749/files/30_24.jpg?v=1600932290ger’s side to the driver’s side. Use a 5/16-inch ratchet to remove the side terminals. Older models with a top post require a 7/16-inch wrench to loosen the terminals. If the car still has a battery hold-down bracket, remove it. This Firebird did not have one as it had long rusted away. Remove the upper radiator hose.
Step 4: Remove Radiator Overflow Tank
Use pliers to remove the radiator overflow bottle hose spring clamp. Slide the hose off the radiator neck nipple. Remove the lower radiator hose. Disconnect the automatic transmission lines (if equipped) with a 1/2-inch line wrench. Remove the tank.
Step 5: Remove A/C Condenser
If your Firebird is equipped with air conditioning, remove the four 1/2-inch bolts that hold the condenser to the support.
Step 6: Disconnect A/C Condenser Lines
Disconnect the condenser lines leading to the evaporator using 5/8- and 3/4-inch wrenches.
Step 7: Remove Carbon Canister Bolts
Remove the two 10-mm carbon canister bolts located on the passenger-side panel near the mount. Support the canister so you do not disconnect the hoses.
Step 8: Remove Cross-Support Bar
The cross-support bar is essentially a very long carriage bolt. To remove it, remove the 9/16-inch nut located on the driver’s side. Two 3/4-inch nuts at the frame rail hold the bumper braces on each side. Remove them to remove the braces.
Step 9: Remove Radiator Support Hardware
Remove the radiator support-mount hardware using 3/4-inch wrenches for the nut and bolt.
Step 10: Remove Core Support and Components
Remove the two upper and two lower 1/2-inch bolts that attach the remaining fender to the support. Remove the battery tray 1/2-inch bolts and the three wheelhouse lower filler panel 1/2-inch bolts. Slide the radiator support assembly forward and off the frame rail.
Once you have the old support on the ground, compare it to the new support. Measure the mounting holes from center to center. Measure the width of the upper and lower tie bars to make sure they are the same.
Connect an A/C pressure gauge to the system to determine if it’s charged. If it is, have it properly removed by a qualified shop. If A/C system was intact and not previously opened, tape off all openings once you disconnect the lines to prevent contamination, which could cause failure in the system.
Mark the driver-side and passenger-side bumper braces before you remove them. They may look different while on the car, but once removed, it is difficult to tell which is which. The last thing you want to do is to have to take everything apart when you are ready to install the front bumper.
Start removing the rest of the components from the old support. Once the parts have been removed, make sure you also remove the clips at the same time and install them onto the new support in the exact same location. Pay attention to which way the thread portion is facing (up or down), the direction the clip was installed, and whether the clips went on top or in between the metal panels. Not following the original orientation could cause headaches later and make rectifying them much more difficult later on. This also goes for any and all brackets still attached to the original support.
Step 15: Remove Radiator Fan Shroud
Remove the radiator fan shroud’s lower two 1/2-inch bolts and upper four upper 1/2-inch bolts. Lift off the shroud and place it to the side. Remove the lower radiator tabs, which hold 1/2-inch bolts.
Step 16: Remove Radiator Cushions
Remove the radiator. Remove the old upper and lower cushions. Install the lower tabs and necessary clips onto the new support. Place the radiator and shroud into the new support.
Step 17: Re-Install Hardware
Remove all other clips, brackets, and bolts, and transfer them to the new radiator.
Now, while the parts are removed, is a good time to clean, paint, and lubricate them for better performance and also so they look good when they are re-installed on the new support. Nuts and bolts work better and hold torque better when cleaned and lubricated.
Once reassembled, install the assembly back onto the subframe. It is a good idea to purchase new core support bushings because the originals most likely will have collapsed, shrunk, and cracked in 30-plus years.
The following techniques are not meant to be quick or to rely on high-viscosity primers to fill body filler sanding scratches that were stopped at 220 grit or less. I am not saying that my techniques are the only way to perform quality body-work, but they have served my thou-sands of customers and me well over the past 20 years.
Once the metalwork has been completed and is to your satisfaction, it is time to perform the bodywork stage. This can be extremely tedious and repetitive, and the urge to short-cut may be strong. But following these procedures will reward you with a beautiful and long-lasting repair that the paint job will reflect. It will be well worth the time and aching muscles.
These procedures are recommended for any body panel. The technique is the same no matter the shape of the panel. The labor costs can be quite high should you decide to have a professional shop perform the bodywork. An average body restoration without rust can average 500 to 800 hours.
All of the body materials described are available at any paint supply store. The body tools are available at any tool supply store. Air-powered tools can be rented if you do not want to purchase them. However, given the amount of time that you spend on bodywork, I recommend purchasing your own tools. Manual tools include sanding blocks. You need a decent-quality DA air-powered sander. Long-board air sanders cost about the same or a bit more depending on what you buy and from whom. It is not unusual to spend $1,000 for a good set of body tools that allow you to complete all phases of bodywork. You also need an air compressor capable of sustaining 60 psi over a period of 5 minutes. Generally a 15-hp or larger compressor is sufficient, but that depends on how large the storage tank is. Although I generally describe PPG products, you can source other manufacturers with similar products.
Sheet-Metal Stripping and Fiberglass Application
The first step is to use the DA sander with an 80-grit paper lightly over the bare metal to clean up the surface so it provides good adhesion for the epoxy sealer. Clean the bare metal with a product such as Prep-Sol. It evaporates quickly and removes any oils and contaminants that could create issues later on.
Use a short-strand fiberglass with resin. I recommend USC Duraglas. Unlike body filler, fiber-glass is waterproof and provides a watertight barrier between the body filler and the surface. Using a 4-inch plastic spreader, mix the fiberglass and resin together on a nonporous mixing sheet. Spread the fiberglass using the spreader from one end of the repaired area in a side-to-side motion.
Step 1: Apply Epoxy Primer to Fender
The stripped metal panel needs to be protected because in most environments, the bare metal panel accumulates some surface rust if not properly protected. Once you have inspected your work and the patch has been successfully completed, apply a primer coat. Next, apply a coat of epoxy primer to the bare metal surface. I use PPG DP50 without any reducer to seal the bare metal and crevices. Simply pour the DP50 into the canister of your primer gun, close the lid, and spray in light, even coats from side to side.
Step 2: Apply Fiberglass to Fender
When applying fiberglass body filler, make sure you overlap the prior spread stroke by a small margin to ensure uniform coverage. I have used USC Duraglas body filler with excellent results for the past several years.
Step 3: File High Spots
Let the fiberglass dry for at least 15 minutes at 75 degrees. Place a body file (also known as a cheese grater) on the ridgelines caused by overlapping the material at a 45-degree angle. With moderate pressure, slide the file back and forth. You want to remove any high spots and thicker material so you don’t waste sandpaper when you are sanding.
As you use the file, stop from time to time and run your hand over the fiberglass to check for high or low spots in the material and to check the contours. If you cut through the material and see metal, you have a high spot. You need to tap down that spot with a body hammer or use a hammer and dolly to correct those areas and start the fiberglass process over again. Taking the time to get the metal panel as straight as possible reduces the amount of body filler needed to finish the repair. This is the first stage of the sanding process. Once you have finished knocking down the high spots, your panel should look something like this. All excess material has been removed.
Step 5: Use Orbital Sander to Sand Fender
Use light hand pressure on a DA sander with 80-grit sandpaper to smooth and rough shape the panel so it conforms to the metal surface. Use a side-to-side motion to sand the fiberglass and thin the material. The process is not about speed, but about getting it right. It may take five minutes or an hour, depending on your skills.
Fiberglass Resin Application
The first pass of filler should be applied in a forceful manner so the filler is pressed into the crevices and pinholes on the panel. For a uniform surface it should not have any air pockets.
Apply two or three thin coats of filler rather than a single thick coat. The thin coats allow the filler to cure evenly. Let each coat dry for approximately 15 to 20 minutes, depending on the room temperature. Make sure the workshop is not too cold when doing bodywork. As with paint, it should be 50 degrees F or warmer when working. Also, it shouldn’t be warmer than 80 degrees when you mix the filler and hardener and then apply it.
Step 1: Fill in Low Spots
A darker area or gradated rings, indicates a low spot. Use a plastic scraper with body filler to fill in shallow low spots. Sand those spots with an orbital sander and 180- or 220-grit sandpaper. Deeper low spots require further metalwork.
Step 2: Clean Surface Area of Panel
After you are satisfied with the shape and fiberglass coverage of your panel, use an air gun to blow out residue from the crevices in the fiberglass. Concentrate on any pin-holes. Clean the area with Prep-Sol.
Step 3: Stir, Select Resin and Add Hardener to Body Filler
Open the can of body filler. Use the best filler available because it is easier to work with and sand. I use Rage Gold body filler. Although it is not the least expensive body filler at $50 per gallon, it is one of the best-performing fillers I have used. Insert a paint mixing stick into the filler and, using an up and down motion, mix the material. Alternatively stir to extract excess air and thoroughly mix the ingredients for several minutes. The body filler settles at the bottom of the can so you need to thoroughly stir it. (To what degree it has settled at the bottom of the can depends on how long the can has been on the shelf at the store.) Once you have thoroughly mixed the filler, place a 4-inch blob on the mixing sheet. The hardener comes in a tube and you need to add a simple ribbon of hardener to the top of the filler that extends from one edge to the other. If there is not enough hardener added, then it will take too long for the filler to set up. If you add too much hardener, you will have very little time to apply and work in the filler.
Step 4: Mix Hardener and Body Filler
Once you add the hardener and mix it with the filler, you need to work quickly because the mixture starts to set up in four to five minutes at 75 to 80 degrees F and becomes unusable. Use a 4-inch plastic spreader and thoroughly mix the hardener and filler until you have a uniform color.
Step 5: Apply First Coat of Body Filler
Using a 4-inch spreader (a 6-inch spreader can be used for larger panels), scoop some filler off the sheet. Spread the filler from end to end with some small overlap on each pass. Hold the spreader at about a 45-degree angle to the surface of the sheet metal and apply even pressure as you push the filler across the sheet metal. Try to use as little filler as possible. A coat should be no more than 1/4-inch thick, but try to keep the coat to about 1/8 inch.
Shaping and Sanding
Use a 120-grit sandpaper to lightly cut the top of the filler surface. Follow up with 180-grit to fully shape the bodywork. Run your hand over the panel repeatedly to check for consistency. Sand as needed to achieve the desired result. Once you are satisfied with the surface switch to 220-grit sandpaper and sand until the 180-grit scratches in the body filler are reduced. Keep running your hand over the bodywork to make sure the panel is staying consistent. Switch to 320-grit sand-paper and sand the body filler until all deep scratches are removed and the surface is smooth. When sanding reverse curves, use the curved softer block at a 45-degree angle on the curved areas.
Once you are satisfied with the surface, apply the DP50 epoxy primer mixed with reducer as specified in the directions to the bodywork area. The next step is to block sand the body to prepare it for paint, which is covered in Chapter 5.
Step 1: File Body Filler
Allow the applied body filler to cure for 30 minutes; otherwise, you disturb the coat and have to start over. Once the coat has fully cured, use a body file to knock down any high spots and ridgelines left from the overlap process. Again, don’t be too aggressive with the cheese grater.
Step 2: Sand Body Filler
Use a long board sander with 120-grit sandpaper and a side-to-side motion. Apply a moderate amount of pressure to sand the filler. A long board sander allows for better control for shaping the panel, and making the surface consistent is critical. Sand until the surface has a uniform finish.
After the first pass of filler sanding, you may see bare metal or fiberglass. That indicates that high spots are still present. Tapping down the high spot area with a body hammer rectifies the issue. Here, minor low spots are still present. They will be taken care of in the next pass of filler.
Step 4: Apply Second and Third Body Filler Coats
Using compressed air, blow out the area of residue for a clean surface and so the filler and panel are clean. Apply the second coat of filler as you applied the first coat. Again, give the panel 30 minutes for the filler to cure. Use a long board sander with 120-grit sandpaper to evenly sand the panel from edge to edge. You may experience some clumping of material on the sandpaper. Simply wipe the clumps off or blow them off with compressed air. Clean the surface again and apply a third coat of filler.
Step 5: Finish Sanding Panel
The top should be relatively smooth at this point, and it’s time for the final sanding step. Use a Dura-Block or similar fine sanding block to perform the final sanding. Work the sanding block from edge to edge and maintain surface uniformity. The flexible sanding block hugs curved surfaces and makes this finish sanding easier.
Step 6: Verify Surface Straightness and Consistency
Check the surface with your hand to verify it is still consistent and smooth. It should be free of waves and any lumpiness. Running the palm of your hand lightly over the panel gives you an indication of its smoothness. If you feel a dip or a bump, be sure to investigate before proceeding.
Step 7: Apply Finishing Putty
Once you have finished sanding the panel and verified that the surface does not have any significant flaw, it is time to apply icing, otherwise known as polyester finishing putty. As with filler, you apply a thin coat no thicker than 1/8 inch. The icing is used to feather the bodywork edges’ small imperfections, pinholes, and persistent minor low spots. Once the icing has flashed, sand as described previously using 180-, 220-, and 320-grit sandpapers. Touch up spots as needed. The surface should be extremely smooth at this point.
Written by Melvin Benzaquen and Posted with Permission of CarTechBooks