Brakes sQueaking!!! Should I use Moly on the pads?

Hi all, Before you flame on telling me to search, I haven't found too much in this forum when I tried. There are some "tricks" some try like backing up fast and slamming brakes to clear the dust....I guess I'll try that. But, I am getting super loud screechy sounds when I am rolling slow with brakes applied....sounds awful. Since I'm CPO, I brought to dealer, they said I have after market pads and the rotors weren't changed. My experience is most of you use aftermarket, so that doesn't surprise me. On my '85, when I switch pads alone, no problems. I have tried high speed braking, no avail. Any advice? I picked up some synthetic Moly to apply to the pad faces, but want to hear from you all first. Any advice?? Thanks, J

There are a number things to start with. Are the pads glazed over or have the rotors been over heated(blue tint to them)? These answers will tell you if more than addressing a squeak only is needed. The way Porsche stops noise on these calipers is by gluing the pads to the caliper pistons with disks that have a sticky back that adheres to the back of the pads and clips into the pistons. These may not have been replaced when the pads were changed. Just not replacing the rotors will not necessarly cause squeaking but any of the above can. The squeak in most cases is not from the rotor surface against the pad. It is from the pad moving freely in the caliper and rubbing.

Thanks Steve....rotors look fine...no tints and not much of a lip on the edges. Are you referring to "spiders" that go on the pistons? Any reference as to what they look like? I'm new to big reds. I did try the high speed stop going backwards about 4 times....it did stop the high pitched scueeks but only for a few stops. I have high pitched and very low pitched scueeks that are incredibly loud. Almost reverberates thru the car.....really annoying. My only literal headache since I've had my car. Anyone hear of the moly that goes on the pads? I just picked some up from autozone, but I'm hesitant to use it. J

Molly I am assuming is a grease? There are other products that glue but there is no need to start all of this if you just buy the "spiders" or anti-vibration shims from the dealer. In the old days we would grease all potential metal to pad backing plate surfaces but I have seen no need for this for quite a while.

You can see the photos of the spiders (for the rear) and the anti-vibration dampers (for the front) here Do you know what brand and model are your pads? Make sure they're not racing pads first. If they are, you may be fighting a losing battle. Good luck. - Ahsai

Thanks fellas....Ahsai..thanks forthe images. Not sure if I have those dampeners/spiders...not easy to tell where they go on the caliper/piston...anyone out there have a close up of their own? Also, not sure what size I should get if I need to install them....I have a c4s,and it looks like there are different sizes. I assume I would get the same as the turbo since the brakes are the same??? J

Hi J, The spiders and dampers go inside the caliper pistons and stick on to the back of the brake pads so they all hide behind the brake pads. From outside you can't tell. To be sure, you have to remove the pads from the caliper. Once you try to remove the pads, it will become obvious how they fit (if they are there). For the correct parts, I would suggest Suncoast since you're in the east coast. - Ahsai

Great....thanks so much. I found this on Renntech....very very helpful....looks like I need the rectangular for the front and both sizes for each rear pad....thanks again. GEEEZZZ...$115 bucks for the dampeners all around....ridic. I'll check tomorrow to see if they are stuck to the pad...if not....gonna replace those. http://www.renntech.org/forums/index.php?showtopic=7065 J

Good that you found that link. I used that link before but I completely forgot they have photos too. I just got a set from Sunset for $86 plus shipping. They (Porsche) just raised the price recently. The set used to be ~$50 a yr ago. And yes, it's ridiculous. - Ahsai

I didnt install mine when I got new brakes so that I could swap pads without taking off the caliper

I just recently replaced my pads with Hawk ceramic pads and I actually just re-used the shims on all the pads - in fact I never took them out from the calipers. I just used a small screwdriver and pryed the shims off the back of the pads - took the pads out...sprayed Wurth anti squeel sprays on the back of the new pads, put them in and pumped the brakes so the pads and shims where tight....no squeel what so ever. I replaced pads on 4-5 different cars using the wurth anti squeel spray and have never had any squeel or noise and have never resurfaced the rotors when putting on new pads....you might just try what I did before you go and but $115 worth of shims....

Do you know what kind of pads you currently have? Racing pads (harder compound) will not heat up adequately in street driving and some squeal is inevitable. As far as the spider/dampener thingys are concerned, they will eliminate squeal for street pads but new dampeners should be applied to new or clean pads so they stick - otherwise they are useless. Another far cheaper and easier install alternative to the spiders is Weltmeister anti-squeal liners. http://www.automotion.com/productpag...-Squeal+Liners . These also will only work when applied to clean or new pads. Personnally, I have discarded the OEM dampeners in favor of the Weltmeister liners on my previous 986S and current 996 with good results.

Ok...update....I pulled the pads on the fronts tonight (no time for rears....will do that tomorrow). No shims on the backs of the pads....go figure. Strange thing is that I can tell where the shims were placed at some prior time....PO must have swapped back and forth for the track I guess. Anyhow, I cleaned the rotors and pads....applied a coat of Moly to the back of each pad (but not on the brake pad portion that has contact with the rotor....I assume I shouldn't put the grease on that....right?). Took the car for a spin....not much change. It is very difficult to determine if the noise is coming from the fronts or rears.....but I'm thinking the rears at this point....lol. Will Moly the rears tomorrow. Also Macho, very very interesting link. The weltmeister pads are almost free compared to buying all the shims! I am picking some up for my next pad swap. THANK YOU!! The dealer inspected my brakes when they did a courtesy check of the car. They advised me that the noise is because the rotors weren't replaced with new pads....I know this is nonsense. They made no mention of shims....just the fact that I have a set of after market pads (can't remember if they are on the front or rear). And I know if they are racing pads....there won't be much of a solution for the noise. I'll report back once I inspect the rears. Thanks for all the input. Should I be putting Moly on the pad faces???? Just making sure....seems it would not be smart to put a lube directly on the pad....please advise. Best, J

Hi J, What you did was right. If you want to experience what brake failure is like, you can put some Moly on the pad faces ...Doh! - Ahsai

Final update.....inspected the rears this morning....amazing how much faster I was than doing the fronts....real easy stuff. I have more difficulty getting the wheel aligned to remount than anything...lol. Anyhow, shim were in the pistons this time, but they weren't stuck to the pad...just sitting there....I looked at one, and it looked fairly new....still not stuck to the pad tho. Anyhow, I reinstalled them in their places. Then put Moly on all the pad rears....a nice coating. Test drive results.....same damn noise. Maybe a teeny bit less (psychological?) but still there. Time for Mintex/Textars. I'll reach out to sunset and suncoast to check on prices...thanks everyone. I'll swap out the fronts first...then the rears in order to solve the issue. Ordering the weltmeister adhesive as well....should nip everything at that point. Best, J

The noise is not from the pistons rubbing on the back of the pads. It is from the sides of the pad backing plate rubbing on the sides of the calipers. Any where the backing plate touches or can touch caliper metal is a potential noise maker. Without gluing the backing plate to the pistons with something, you will need to grease pretty much the whole backing plate sides and all and when it wears down do it again. You can re-use the old spiders if you clean them well and apply aftermarket available glue. Also, when re-using rotors they need to be machine turned a small amount or by hand you can sand them to remove the previous pad material embedded in the metal. Without doing this you now have the new pad material being applied over the old pad material. Most times this does not work well decreasing stopping grip and causing wierd vibrations which can lead to SQUEAKS!

Steve, Thanks so much. I put a good amount of grease on the entire portion of the backing plate. Every bit of it is covered. However, I placed them back in front of the shims....should I take the shims out and put the treated pads in without the shims? What adhesive would you recommend in placing the shims back on? If I have Moly on the back, maybe I don't need the shims?? Thanks so much.

If it was my car I would buy pads, rotors, new spiders and start all over. To save what you have I would clean all the grease off (may be hard but use a solvent and do not get it on the pad material). Sand the rotors by hand with 1,000 grit paper. Sand the pads with the same. Take brake clean and clean the rotors very well along with the calipers and backing plates on the pads. Coat the backing plates with Berrymans brake disk quiet(really need the spiders IMO) and re-assemble. This is the best chance to stop the noise but still may not work if the rotors and pads cannot be cleaned enough to start the embedding process all over again. I have had good luck with the Berrymans though.