Questions and Answers

Isuzu Impulse Brake Shimmy Q. I have an 1984 Isuzu Impulse that shimmies when I step on the brakes. I've been told that if it happens ONLY when I step on the brakes that it is a warped or overly thin disc rotor. My car has four wheel disc brakes and although it feels like it's coming from the front, I really can't be sure.

My question is this: How do I tell which of the discs is warped, and whether it's the front or rear?

Thanks,
David

A. You were told right, a brake shimmy is almost always caused by a warped rotor. If you can feel the shimmy in the steering wheel and brake pedal, it is the front rotors that are warped. If you don't feel it in the steering wheel and just the pedal, it's the rears.

If there is any question, then it would be a good idea to have all four rotors checked for proper thickness and, if they are above the minimum, have them resurfaced.