Constant brake squeal
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6th Gear
Joined: Feb 2002
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From: Northwest
Constant brake squeal
I recently changed my brake pads for the first time on my 964 (used to have a '80 911SC) and after bedding the pads and driving it for a couple of days am getting a constant brake squeal sound from the passenger front side. The sound happens when the brakes are not engaged and seems to be worse when the passenger side of the car has weight loaded on it in a turn. The squeal seems to go away at higher speeds or with increasing brake pressure. (I am using Pagid's but this is not the typical race pad squeal under braking).
My question is (and there may have been a previous discussion about this) do the circular tabs that were glued to the old pads need to be glued to the new pads? I did reinsert the tabs, but did not glue them to the new pads. Could this be the cause of the brake noise?
Essentially, what is the "correct" process for inserting new brake pads on the 964? I know there are a lot of you out there that change pads frequently, so any help is appreciated.
Also if you know what these circular disks are called and where replacements can be ordered that would be helpful also. Wait, finally, what kind of glue is used if gluing is necessary?
Thanks
Erik
My question is (and there may have been a previous discussion about this) do the circular tabs that were glued to the old pads need to be glued to the new pads? I did reinsert the tabs, but did not glue them to the new pads. Could this be the cause of the brake noise?
Essentially, what is the "correct" process for inserting new brake pads on the 964? I know there are a lot of you out there that change pads frequently, so any help is appreciated.
Also if you know what these circular disks are called and where replacements can be ordered that would be helpful also. Wait, finally, what kind of glue is used if gluing is necessary?
Thanks
Erik
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From: springfield, MO USA
Erik, don't know what kind of car you are driving, but I noticed on my C4, there are several different diameters of the discs, depending on the piston position, and front / rear!. It seems that each piston has it's own size. I learned this by accident.Seems not to make any difference that the pad sizes are the same (remember mine is a C4, does not have the weenie small rears of the C2) In my case, I kinda pasted the discs on using Gunk "disc brake quiet" aerosol. Not sure it's really necessary, but I had it on hand.
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[quote]<strong>My car is a 93 RS America. It has the same size pads front and rear. Same size 4 piston calipers front and rear also, I believe.</strong><hr></blockquote>
The RSA has 40mm / 36mm pistons in front and 30mm / 28mm pistons in the back.
The RSA has 40mm / 36mm pistons in front and 30mm / 28mm pistons in the back.
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Erik:
On stock equipment, the pads use vibration dampers and damping plates to silence the brake noise. You MAY want to see if a local Porsche or parts shop can give you a blow up diagram because as described in the manual it's not really clear how this all goes together, and a picture in this case may be worth a thousand words. The AllData web site at <a href="http://www.alldata.com" target="_blank">www.alldata.com</a> has some TSBs that outline the procedure if you don't mind paying $20.00 a year for subscription to their service. The AllData site doesn't have very clear diagrams either. I don't know if your Pagids require the same backing plate (or if it even needs one) since some aftermarket pads are apparently intended to be installed differently. The damping plate on stock equipment is supposed to have an adhesive installed on it.
As far as your noise goes, I would expect a squeal to occur only when applying the brakes, not all the time, had the pads been installed without the damping components being properly "glued" and assembled. If, on the other hand, you have a pad dragging AND you're damping isn't quite correct, then you may get a constant squeal. This kind of implies one of your calipers is sticking.
Hope this helps
Bill Wagner
On stock equipment, the pads use vibration dampers and damping plates to silence the brake noise. You MAY want to see if a local Porsche or parts shop can give you a blow up diagram because as described in the manual it's not really clear how this all goes together, and a picture in this case may be worth a thousand words. The AllData web site at <a href="http://www.alldata.com" target="_blank">www.alldata.com</a> has some TSBs that outline the procedure if you don't mind paying $20.00 a year for subscription to their service. The AllData site doesn't have very clear diagrams either. I don't know if your Pagids require the same backing plate (or if it even needs one) since some aftermarket pads are apparently intended to be installed differently. The damping plate on stock equipment is supposed to have an adhesive installed on it.
As far as your noise goes, I would expect a squeal to occur only when applying the brakes, not all the time, had the pads been installed without the damping components being properly "glued" and assembled. If, on the other hand, you have a pad dragging AND you're damping isn't quite correct, then you may get a constant squeal. This kind of implies one of your calipers is sticking.
Hope this helps
Bill Wagner
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6th Gear
Joined: Feb 2002
Posts: 6
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From: Northwest
It seems I didn't file enough off of the bottom edge of the pad and it was rubbing on the inner lip of the rotor. Just a brake pad seating problem. Nothing to do with those vibration dampers. I pulled the pads, filed a little more of the edge and the noise seems to have subsided.
Thanks for your help.
Erik
Thanks for your help.
Erik
