Break Squeak
07-16-2010, 07:15 PM
#1
Track Day
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Break Squeak
Hi everyone, I'm having an issue with my brakes that's driving me crazy.
The front brakes on my 928S started squealing about 4 months ago, I've never had this issue with the car before. To date I've replaced all the brake pads and put brand new rotors on the front. This has not stopped the squeal and in fact it's even worse than it was before. there is now a squeal sometimes at low speed driving (5 mph or less) without even applying the brakes.
What could possible be wrong?
The front brakes on my 928S started squealing about 4 months ago, I've never had this issue with the car before. To date I've replaced all the brake pads and put brand new rotors on the front. This has not stopped the squeal and in fact it's even worse than it was before. there is now a squeal sometimes at low speed driving (5 mph or less) without even applying the brakes.
What could possible be wrong?
07-16-2010, 07:50 PM
#2
Team Owner
you might need to rebuild the calipers.
it would also be helpful to put the car info in your post
it would also be helpful to put the car info in your post
07-16-2010, 11:24 PM
#3
Supercharged
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You need to really clean the calipers, and grease the sides where the pads ride in the caliper along with where the pistons contact the pads. Sometimes a softer pad will eliminate the squeal, but then you have the dust issue.
07-16-2010, 11:55 PM
#4
Car is an early '86. We've got Hawk pads on, new rotors, been through the calipers and lubed them up real well.
The brake system has been flushed.
We changed the pads and the rotors appeared close to new, so didn't change them. The pads did not get bedded in before Michael came back and wanted new rotors put on. So I installed new rotors. I'm guessing that these pads/rotors have not had enough miles on them to be bedded in yet. Was also unaware that the squeak was still present, but will look in to it further.
The brake system has been flushed.
We changed the pads and the rotors appeared close to new, so didn't change them. The pads did not get bedded in before Michael came back and wanted new rotors put on. So I installed new rotors. I'm guessing that these pads/rotors have not had enough miles on them to be bedded in yet. Was also unaware that the squeak was still present, but will look in to it further.
Last edited by SeanR; 07-17-2010 at 11:37 PM.
07-17-2010, 04:05 PM
#6
Drifting
How about some of that "disc brake quiet" that comes in the aerosol can? The reason it works is because brake noise comes from the area where the pad makes contact with the caliper. Resist the natural urge to use the cheap stuff in the foil packets, that stuff is for rednecks and white trash.
Like most Porsche people, I know there's also an overwhelming tendency to believe that "my Porsche is special, such pedestrian fixes can't possibly work on it." Guess again. It should work fine.
Like most Porsche people, I know there's also an overwhelming tendency to believe that "my Porsche is special, such pedestrian fixes can't possibly work on it." Guess again. It should work fine.
07-17-2010, 07:33 PM
#7
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I had the same problem in the rear. New discs, new pads. Tried everything. I replaced the pads with the "PBR" brand (Australia) bought at a local car part store (NAPA). They told me those were "organic" rather than "metallic"! Well, organic worked fine for me! No more issue. Also, a lot less dust than the previous pads. Braking is just fine.
Michel
928 S4 89
Michel
928 S4 89
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07-17-2010, 08:55 PM
#9
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Get someone to follow you on a bicycle and determine for sure where the noise is coming from. If the rotors develop a lip they can howl even when the brakes are not applied, maybe this is your problem and it's the rears. Which pads did you get? Maybe you chose a loud compound.
07-17-2010, 10:15 PM
#10
Team Owner
the other possibility is worn spindles if you have the hub off check the lower inner seat for the wheel bearing i have found that some spindles seem to get wear marks then the bearing wont fit firmly on the spindle this leads to a loose fit of the hub .
No you should not try to adjust the play out by tightening the bearing more than its specified , (with a washer that can be pushed with a screwdriver)
But its worth a try to reset the spindle nut .
This kind of play would be most noticeable when backing up then applying the brakes you can feel the extra distance needed in the pedal
No you should not try to adjust the play out by tightening the bearing more than its specified , (with a washer that can be pushed with a screwdriver)
But its worth a try to reset the spindle nut .
This kind of play would be most noticeable when backing up then applying the brakes you can feel the extra distance needed in the pedal
08-06-2010, 07:17 PM
#12
Michael, when I get another MAF (air flow sensor) in, I want to test it on your car.
08-07-2010, 02:27 AM
#13
Rennlist Member
Sean said these were Hawk pads but did not say which variant, if they are Hawk Plus pads [road/track variant] forget it- they squeal something awful at low speed/street type braking [i.e. when coming to a halt]. They are quite OK under heavy braking and that is why one has them.
I also agree with earlier post- putting a pressure washer on the calipers to flush the dust out helps a bit but not for very long.
Regards
Fred R
I also agree with earlier post- putting a pressure washer on the calipers to flush the dust out helps a bit but not for very long.
Regards
Fred R
08-07-2010, 05:17 AM
#15
Drifting
Haven't seen anti-squeal shims mentioned in your original post Michael. Were they fitted along with the new pads? I understand that copper grease at rear of pads (careful not to get any on front surface) and - as another poster said - at edges of pad where they meet the end plates also eliminates squeal, but that the Porsche shims work for longer (but pads should always be greased at edges).
