Pulsation in the brakes won't go away

I have a nasty pulsation/vibration when I brake above 40 mph. I’ve already had the front rotors and pads replaced along with wheel balance, alignment and tire rotation. Firestone said I don’t need rear brakes done but I think they’re wrong. Anyone have a thought about whether this is a brake issue or something else?

Well that vibration can come from the front or back. The rear rotors or drums can cause the problem. Likely Firestone only looked at the wear on the pads/shoes and that does not tell them about the rotors or drums.

Make sure someone takes a close look at those rear rotors/drums. Also have them check out the rotors/drums on the front. They can be bad out of the box, or they can be warped when someone uses an impact wrench to remount the wheels.

I suspect you have rotors not drums, but I can’t be sure with the information provided.

Go to a brake specialty shop if you can find one. Firestone and other chains are focused on part replacement, not diagnostics.

You can figure out something about the rear by finding a clear stretch of quiet road for test driving, get up over 40 (or whatever speed is best) and slow down using only the parking/emergency brake. If you don’t get any pulsation then the problem is probably not in the rear.

But, as wentwest said, Firestone probably isn’t the best place. I would find a shop that does front ends since you can also get these kinds of pulsations from worn front end parts such as tie rods or wheel bearings. A local, independent shop that does alignments and brakes would be a good bet.

My guess also is the back rotors are warped. The rotors on the front were replaced but the pulsation was still there so I took it back and had them machine the new front rotors flat. That made things a little better but not 100%. At this point I’ll probably just replace the rear rotors & pads.

Thanks for the tip I wouldn’t have thought of that. My best guess is that the rear brakes are causing the pulsation so this will be a good way to check it out.

This is the last time I go to Firestone.

There is another way to find the source. Jack up each corner of the car, and spin the wheel by hand while someone slowly applies the brakes. You’ll actually feel the pulsation on the source wheel(s). Simple, but it usually works.