Rear Brake causes rotor warping

[jwater7]

I'm having some trouble with the passenger-side rear brakes. I've had the brakes professionally done a couple times now, and I'm starting to loose hope this can get fixed.

What happens is after a period of time, I start to feel pulsating in the brakes and a "eee eee eee" sounds from the brake pads. I believe the rotor is getting warped but I can't figure out WHAT is causing the warping. Could it be the brakes are sticking somehow? Could it be the bearings? The last time the brakes were done only one of the pads were worn, but this time, they seem to be wearing evenly. Could it be the e-brake?

Thanks for any input and ideas on this

 

[SVT32VDOHC]

94-04 Mustang rear caliper brackets are notorious for locking up. Pull the calipers off and make sure the caliper slide pins spin back and forth and pull in and out freely. If they are locked up, buy new ones.

 

[jwater7]

They feel pretty free moving this time. These ones are only a month old.

 

[SVT32VDOHC]

Hmm...that sucks. How about the caliper itself? Is that sticking?

 

[BrittGT]

94-04 Mustang rear caliper brackets are notorious for locking up. Pull the calipers off and make sure the caliper slide pins spin back and forth and pull in and out freely. If they are locked up, buy new ones.

+1, I had to do this same thing last year. Caliper bracket wouldn't move.

 

[jwater7]

Well, I checked and re-checked the rotor, and the rotor actually seems fine. It looks like the imbalance is somewhere further down the line. Could the shaft be bent or something? Or is there a more common problem that I can check first?

Thanks

 

[urban96]

may be a bent axle that would also cause the wheel to slightly wobble too

i had the slider pins on mine sieze up b4 too, new sliders solved the problem

 

[SVT32VDOHC]

Have a friend drive behind you and see if that corner is wobbling. If it is, change the tire/wheel first, to see if that is what's bent, but if it still wobbles, it's the axle shaft. Has the car ever been curb shot before?

 

[Zero_chance]

When the rotors were machined, was the inside of the rotor seating surface cleaned with a cookie wheel? And where it rides on the axle? A lot of times rust build up there that doesnt get cleaned will result in a low spot on the rotor that eventually leads to a pulsation. At first, you might only hear a similar noise to what youre describing as the high area caused by rust buildup comes around and contacts the pads at rest. Water intrusion behind the rubber boots on the caliper slides is what causes the slide pins to seize. All you have to do is free them up, clean them out and put a good amount of dielectric greases on the cleaned slide pin and it should be good. Sometimes the boots themselves will have to be replaced. Very rarely do you have to replace the entire bracket unless you dont have the tools the get the old slide pin out. Sometimes if theyve been neglected for a good amount of time, they need to be heated up with a torch. Back to the main point, an on car brake lathe is very good at eliminating repeat brake pulsations as long as the hub surface doesnt have excessive runout. On car lathes cut the rotor to the center line of the axle or spindle, which negates runout from stack tolerances. i.e if you have a thousandth of runout in the hub and a thousandth of runout in the rotor, put them together and you have a good amount of runout at the far end of the rotor.