By Ralph Kalal
When all else fails in removing a brake rotor that has rusted onto the axle stub, there are two options: hit the rotor until it comes off, or use a “puller.” Of the two, the puller is the better choice, especially if you wish to preserve the rotor.
Pullers, sometimes called “wheel pullers” (not, however, a “steering wheel puller”) come in various sizes. They have arms that hold the thing to be pulled, and a central bolt that pushes against a stationary part of the vehicle, such as the axle stub. The idea is that the puller evenly distributes the pulling force from the central bolt to he arms, until the pulled object is removed. Pullers are the common way of removing components that are pressed onto a shaft, such as the harmonic balance at the end of a crankshaft. For removing a brake rotor, you will require a three-arm puller—a big one.
Pullers are rather expensive, so it makes sense to rent one, instead of buying it.
Using a puller to remove a rusted brake rotor is somewhat dangerous, for several reasons. That doesn’t mean you shouldn’t use one. Using a chain saw is dangerous, too. It means you should be attentive to the risks and take the appropriate precautions.
First, the puller can slip. Second, the rotor can break, that can send bits of metal flying. Third, when the rotor breaks free, the puller is suddenly relieved of all pressure and is likely to fall away from the vehicle. The rotor is restrained by the lug nuts, but the puller isn’t and will suddenly come loose and fall.
So: never use a puller on a brake rotor without wearing safety glasses. Never put yourself under the puller. Keep everyone else away when you are tensioning the puller.
It is, however, much easier to position a three-arm puller if you have an assistant. The assistant can help hold the puller in position as you initially tighten the puller. Be sure the assistant also wears safety glasses and, once there is enough tension for the puller to hold itself in place, have the assistant step back as you add tension to the puller.
The bolt will rest on the axle stub end, and the puller arms will hook around the back of the rotor. If they will rest on the rotor surface, use thin wood or small pieces of cardboard to protect the braking surface from the metal of the puller. As soon as you have enough tension on the puller that it will hold itself in place, have your assistant retreat to a safe distance.
Turn the bolt on the puller slowly, gradually applying pressure to the rotor. There is always a risk that using a puller will break the rotor, because the force pulling on the rotor is at its outside edges, while the rust is holding it in place at the center.
There is always a risk that the force applied by the puller to the brake rotor will crack the rotor. Should this happen, you should not feel that you have erred. There are some instances in which a severely rusted brake rotor simply cannot be removed intact.