someone972

iTrader: (2)

This is on PBR rear brakes on a 4th gen rear from ~1995ish. Just replaced the rear rotors and pads a couple hundred miles ago and it's got a terrible squeal with light braking pressure, which goes away when the pressure is either let up or increased. Rotors and pads are BrakeBest (with the pads being the more expensive of the two options). After it started squealing the first time, I really slathered the brake grease over all areas where things touch and move, and it got rid of the squeal for a few weeks but now it's back.

Is there a common cause of squeal for the PBR brakes? Is it the brand of pads or rotors? Any suggestions on how to fix it or narrow down the cause? The squealing is driving me nutty, especially since it's right in the pressure range I use most of the time .

the_hamturdler

I've got the same issue. New pads and rotors, good quality but they squeal like mad.
Maybe have a shop check the runout on the new rotors? Even good quality new rotors can need to be turned sometimes.

Did you bed the new brakes in? Are the machining marks still there? If not, I'd start there.
I attempted to bed my brakes in, but the brake bias doesn't give you much pressure in the rear to bed them in with. I've got 1.5-2k miles on my new brakes and they still have the machining marks, which is way longer than I've ever seen.

Hopefully someone else who knows a bit more can chime in.

someone972

iTrader: (2)

Haven't had the rotors turned, might be an option if I can't find anything else. Machining marks were still there for a while, not sure if they are still (have to check). Although I've been fighting the rear brakes trying to get them to work properly for a while now. They can barely stop the rear wheels when up on stands even with heavy brake pressure, and I can't lock them up on gravel. So I wouldn't be surprised that they haven't bedded properly. I've been trying to get them to work better, and have new rubber lines all around, a new (very well) bench bled master cylinder, new pads, new rotors, and the stiffer spring in the prop valve. Could potentially still be a prop valve problem, but I'm getting some reman calipers just to be sure they aren't seized up.