New Pads/Rotors noises

[Bluemustang]

OK, so I worked on it all day yesterday. Basically re-did everything.

I sanded down the rear pads to remove the glazed surface. Sanded down the rotors. Clean off the wheel hub again, applied anti-seize once again. Cleaned the anchor plate, installed new anti-rattle clips and lubricated them as well as the ears of the pads they go into. Applied WD40 to the rear caliper piston boot. And I bled off the driver rear caliper that I messed up before so pedal feel is restored now.

Noises have gone down and didn't get any horrible noises applying the ebrake or shifting into the reverse - drive. However, I suspect it's only better because I removed the glazing on the pads. I think the larger issue is my calipers. I think they are binding up somehow. This would explain how the glazing occurred and also why when I swapped out the stock pads, the stock rear pads were gone gone while the fronts were OK. Same thing on that spirited run last week - fronts were OK, rear pads glazed AF.

I used the penetrating oil on the caliper boot in hopes that it was just dry/seized up and maybe that would help. Unfortunately, I see no way to really test if that did anything except to go on another spirited braking run and see if it happens again. I really don't think pads, especially perf. street pads, should glaze over on the street. I just can't push it that hard like you would see on a track.

My other theory is possibly e-brake adjustment. Perhaps that was out of adjustment all along and it's being partially applied even when not engaged, but that seems like a long shot.

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[Bluemustang]

I am just thinking out loud here... if my theory is correct and the calipers are sticking, I should be able to tell before the pads start glazing. For instance if after some driving, the rear wheels feel hot, moreso than the fronts, then it will be a sign. I think I already know because I have the evidence of the glazed pads. But, did WD40 on the piston boot do anything? I'm gonna say doubtful. Also, when I disassembled the brakes yesterday, the caliper piston was already pretty much compressed. I would expect it to be fully extended since I had been driving it. Typically you have to use the piston compressor tool once you're done with it. I only had to compress the piston slightly on the passenger side in order to re-assemble everything. The driver side rear piston was already flush. Again I find that odd. Also, regarding the glazed rear pads - it was both sides glazed, not just one.

Now just thinking forward here - if I do need to replace the rear calipers - Does it make any sense to go aftermarket? I'm guessing not and that could affect brake bias in a negative way? And if I do buy new rear calipers, is there anything I else I need? I can buy just the calipers on the Ford parts site but I have no idea what that comes with and what else should be replaced along with it. @NightmareMoon ?

 

[NightmareMoon]

Have you made any changes to your traction control or ABS systems?

I doubt there is an issue with your rear brakes sticking but I’m not an expert on much, let alone this.

I dont think you can judge if its sticking by temperature versus the fronts alone. I’d drive it a while and see if they glaze again. What pads are you using? Are they the stock pads?

 

[Bluemustang]

Have you made any changes to your traction control or ABS systems?

I doubt there is an issue with your rear brakes sticking but I’m not an expert on much, let alone this.

I dont think you can judge if its sticking by temperature versus the fronts alone. I’d drive it a while and see if they glaze again. What pads are you using? Are they the stock pads?

No changes to traction control or ABS. Pads are GLOC GS-1. As of right now, I have reason to suspect the piston boot is to blame. Either its binding or its cinched I think. I didn't realize what it meant at the time but when I touched the piston boot I could hear air come out. And it didn't look uniform around the piston like it should.

The only logical explanation for me glazing the rear pads like I did is pads dragging on the rotor. The fronts were fine. The question is why are they dragging. Points heavily towards the caliper. Sure it could be a number of things but I'd bet that I didn't compress the piston correctly causing it not seal that well.

The rear pads were definitely glazed. It looked like polished granite or marble. Shiny and smooth to the touch. Noises have subsided but need to resolve the underlying cause. At least now I have a good idea where to look.

 

[Bluemustang]

So for peace of mind, I asked my mechanic to look at it. He didn't find any issues with my installation and says the rear wheels are spinning freely like they should. Possible that my work lubricating the caliper piston boots did some good?

He tried to find an issue but didn't find anything. The only other thing Tim Hilliard mentioned was the parking brake, which I did nothing to. Although IDK why I would have to touch the parking brake adjustment just swapping pads and rotors.. Has anyone else had to adjust their parking brake doing this type of work? I mean I think all you're supposed to do is compress the caliper pistons so it is flush with the edges of the cylinder.

The noises are one thing, but I was hoping my mechanic would find a problem so I could figure out why my rear pads glazed like that. Maybe I did push the car too hard? But then why would only the rear pads glaze over?

According to Tim, the rear brakes were hanging up but as I've said I went through everything and now my mechanic has done the same and he says all is good. So I am disappointed that I was not able to see what was causing it.

My hope is the issue doesn't return.

 

[Bluemustang]

OK, so I've been driving it more the past few days. Brakes still feel good, maybe even a little better after working on it. I did see some advice (now this was re: an older Mustang but I think it's a similar rear brake setup). That was crank the parking brake up and down several times to reset it to accommodate the new pads. I know our rear calipers has the parking brake integrated into it. Anyhow Idk if our cars work in the same way but I tried it and it seems to have helped.

I felt the wheels the other day after a brisk drive and the front wheels felt noticeably hotter. The only noise I hear is a slight squeal occasionally at very low speeds and a certain pedal input. At this point I have to assume it's normal. Might be this combination of pads and rotors as I have not seen anyone else running the same combination.

 

[Nagare]

I'll give the parking brake stuff a try, I also had some squeal/screech when turning left, I fixed that by pulling back the brake shield.

I'm still having some squealing at low speeds and with certain pressure, if I slam on the brakes, no noise. If I do any of the regular scooting forward at a red light, brake squeal happens. I went with Powerstop drilled/slotted rotors and Z16 pads which are supposedly silent, hopefully if I'm able to get a proper bedding process done everything settles itself but with the weather we're having I don't want to chance anything on the streets right now.

 

[Mr2raw]

OK, so I've been driving it more the past few days. Brakes still feel good, maybe even a little better after working on it. I did see some advice (now this was re: an older Mustang but I think it's a similar rear brake setup). That was crank the parking brake up and down several times to reset it to accommodate the new pads. I know our rear calipers has the parking brake integrated into it. Anyhow Idk if our cars work in the same way but I tried it and it seems to have helped.

I felt the wheels the other day after a brisk drive and the front wheels felt noticeably hotter. The only noise I hear is a slight squeal occasionally at very low speeds and a certain pedal input. At this point I have to assume it's normal. Might be this combination of pads and rotors as I have not seen anyone else running the same combination.

Sorry to reply to an old thread. I recently replaced rotors and used R10 front pad and R8 rear.
At a dead stop turning the wheel, and reverse creates a clunk sound as you mentioned.
Also at low speeds, you can hear squeal with pedal pressure....
I am experiencing the exact same thing.

Did you resolve your issue? If so, how did you do it?

 

[Mr2raw]

Yeah I know they squeal when you apply the brake pedal. I m referring to some faint squealing under normal low speed accleration. this is with ZERO brake pedal applied. Are you experiencing this faint squeal too? Under low speed driving? No brake applied?

 

[Mr2raw]

So, after some more extended driving, I actually noticed the squealing under normal driving (no brake pedal applied, only accelerator applied) is getting worse. I find it a little hard to believe how that is considered normal. Can you elaborate on how the shims play a part in it?

If gloc pads causes this squeal sound under normal driving while no braking is being applied, that means the pads constantly rub the rotor then. Does it mean the pads and rotors will start to wear out prematurely?

 

[Mr2raw]

Thanks for the reply man.

It is my first time using race pads so I didn't know what to expect. They did perform very well at the track and I was very happy.

I don't think I'll be swapping out pads tbh because I rarely drive the car because it is essentially a weekend car and occasional track car now.

But that sucks. Quiet annoying that going forward, the car will continue to squeal even when I am not applying the brakes. At least I know it won't be wearing out my rotors faster.

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