johnfm

Heeeellllpppppp!

After installing anit-squeal shims on all four corners at my yearly service last week, my brake squeal return after about 30 miles.

I am officially not happy.

Pads are 5000 miles old, as are the rear discs. Front discs are older, but still fine. Pads are original porsche standard pads as far as I know.

Anyone got any suggestions that doesn't involve a shotgun????

Look forward to a solution (but doubt there is one!!)

Adrian

Dear John,
Pull out the pads and file a small angled edge around the pad. The side that contacts the disk. You may find that they are catching the disk wear ridge. The only time I have ever heard my brakes squeal is when they are wet and the rotors cold,
Ciao,
Adrian
911C4

Ade - C4 91

Hi,

My rear pads also squeal when hot. I've just learned to ignore it.

New pads perhaps 2K miles. They were fitted without the sticky pads behind the anti-squeal shims at first, but then clunked when the brakes were applied. Got JZM to add the sticky pads and now they squeal. It must have something to do with heat expansion and clearence.

Ade.

horst

also, remember, that even tho the pads are the same front/rear, and the calipers LOOK identical, the shims are different front/rear. Drove me crazy till I found out with both in my hands.

johnfm

Mine squeal when warm, but I'll try filing the pads (actually I'll get the mechanic at Strasse to do it as I don't have the facilities or time!!)
Disc wear ridge??? Is this the little lip that runs on the extreme edge of the disc?? - my mechanic said the discs were "lipped" - I assume they are desinged to wear like this to give an easy indication of how much disc is left. How pronounced can the lip be before discs need replacing?

964spd

Hi,
Just want to say that my brake squeaks even after being in two different garages, with three different sets of brake pads, one pair of rotors and anti-sqeal compounds. It still squeals from rear end sometimes and every time when reverse.(Really embarrassing!!) The garages can't do nothing anymore. And I plan to put on a whole big reds and pray.

Adrian

Dear John,
Yes this lip shows how much the disk is actually worn. The bigger lip the bigger the chance of squealing because the edge of pad tends to rub up against this lip. Well that is one cause. You ask about the limits. You are allowed I think 2mm but I am not sure if that is each side or combined. I will have to check the limits in the manual. They are in there somewhere.
Here is a note written by somebody I know quite well actually. The context of this statement is that you cannot fix the corrosion problem unless you fix the corrosion problem. Once solved then grinding the edges, using anti-squeal pads and compounds will work to counter things like grooved or lipped disks catching the pad.
Ciao,
Adrian.
911C4

Brake Squealing
One of the most common problems reported by 964 owners is brake squealing. The causes of this annoying problem are many. This section will provide some information on the subject, some basic steps that can be taken to avoid the problem and the Porsche recommendations, which also assist.
On the 964 regardless of model or version the most common cause of brake squealing is the steel backing plate under the brake pad is not sitting flat in the calliper. This is primarily caused by corrosion in the calliper caused by the fact that two dissimilar metals are used. Alloy and steel. No matter what steps are taken to get around this problem. The corrosion must be removed/repaired to solve the problem. Anti-squeal compounds and other attempted cures at best only work for a short time. Most never work at all. Trimming by grinding down the brake pads also does not work for long. The corrosion must be removed and the backing plate made to sit perfectly flat so it moves evenly.

Bill Wagner

Just to add to what others have said, I would do the following:

1. DEFINITELY isolate the source of the noise. When I first discovered this problem on my car, I SWORE it was the rear brakes but it turned out to be the front. A way you can isolate this is to take a hose with a power nozzle and flush the area between the pads and the rotor. THE ROTORS MUST BE COOL BEFORE YOU DO THIS, OTHERWISE YOU MAY WARP THE ROTORS. Do this one wheel at a time. Eventually the offending wheel will become obvious because the noise will either reduce or go away completely FOR A WHILE...but not a long while. My noise would usually come back after flushing within 50-100 miles.

2. Once the offending wheel is located, you need to get your hands dirty and try to find the source. One source is that the dampers actually bust off with age, and the other, more insidious one that Adrian mentioned is corrosion. I would be willing to bet that corrosion is the culprit most of the time for cars that have had this worked on unsuccessfully because often the corrosion looks very minor, but the corrosion actually produces little rust particles that allow the pad to seat incorrectly, and thus vibrate causing noise. Granted, it's by a small amount and easy to overlook but it doesn't take much to make them squeal.

3. Others have reported that switching to MetalMaster pads improves or eliminates their problems. Porsche pads are good, but the dust they generate is unbelievable. Less dust means less exposure of the brake areas to exposure to the dust which will eventually work it's way down into cracks and crevices of the brake system (particularly corroded ones) and just make the problem that much worse and your wheels will stay cleaner too.

It's a PIA, but it is fixable!

<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

johnfm

Thanks Bill & Co

will give it all a go.

Marc '91 C2 Coupe

Hi gang,

Not much to add on the technical side, except for the fact that my brakes do NOT squeal one bit, so it IS possible to get this done right. I had all pads replaced two months ago. No squeal before, none afterwards.

Only problem is, I didn't do the work myself, and nothing special was done that I know of. I believe the new pads were OEM.

Good luck!

Marc

malc elliott

Hi,
Like johnfm I had my rear discs and pads replaced at Strasse recently and now have annoying squeal on the nearside rear where there was none before. I tried removing the pads and coated the edges and back of pads with copaslip(copper grease.)
This improved slightly but is still squealing on just the one brake. From memory I think the pads are Textar.
As everything is new this has been puzzling me too as in 12 years of ownership this has never happened.
Malc 90 C2 Cab