Brake change shims for GT3?

[LVDell]

I have done the brakes several times in my GT3 but never used the shims since I swap between street pads and track pads so much. I am just going to stick with my Pagid RS19's for 24/7 duty and install the shims to remove some of the dreadful squealling.

I have been getting different answers on what is the shim type (bars/spiders/etc) and number of them used for the GT3. So, what do I need as far as parts for the brakes to install the correct number of shims?

FYI.....2004 GT3 with iron rotors.

TIA! :thumbup:

Edited March 15, 2007 by LVDell

[clord]

Hi LV.... Well....I can get you the part numbers of the stock "anti-squeel" shims for front and back.....but..... I don't think you will eliminate the noise with the factory shims. I've tried running many different Pagid compounds on the track and on the street on three different porsches and several Audis. Bottom line: they all are great on the track and they ALL make noise on the street....even the blue sports that are supposed to be street/track pads....whether or not I've run shims. I've used Porsche shims, Pagid shims (on the blue sports) and even home made stainless steel shims (DO NOT TRY THIS...ask me why later). As I said, the Pagids are a great track pad, but, after being toasted on the track, my experience is that they will squeel, no matter what, on the street. Let me know if you want the factory shim part numbers......or. drop by my garage..... I've got a good supply of them all.

[LVDell]

I'd drop by but that is one heck of a drive for me :)

The shims were a last resort since I am so tired of the **** squealing on the track where I thought it would be less.

[clord]

Yeh.... I have 993TT Big Reds on my Audi TQ, and, even for that, I've reverted to stock, Porsche factory pads for that caliper. They are quiet and work just fine for the street. Sometimes, new Pagid pads on new or buffed up rotors (break the Pagid deposition glaze) will be quiet....but, if you get them hot on the track, they revert to very noisy.

[charlesl]

Gang,

I got really, really tired of sounding like a school bus when approaching an intersection or something. After some work, I eliminated about 90% of the brake squeal on my 04 GT3. Here's what I did:

1) Take the brake pads out of the caliper.

2) Remove the anti-squeal shims. I did not replace them.

3) Clean the inside of the caliper and the metal back of each pad. These surfaces need to be really clean.

4) Cover the ENTIRE back of each pad with a thick coat of red anti-squeal compound. The instructions say let it dry for 10 minutes before replacing but I found it took about 30 minutes. You want the compound to be tacky. Again, cover the entire back of the pad. Not just the spot where the pistons will hit. The compound itself changes the resonant frequency and will help reduce squeal as well as bonding the pad to the piston.

5) Squeeze the caliper pistons back into the caliper. Just reach in there and squeeze them one at a time with your fingers. No need to use a tool here.

6) Slide the pads back into the calipers. Be careful to keep the pad against the rotor when you slide it in. You don't want all of your anti-squeal compound to be scraped off on the edge of the caliper.

7) Replace all of the retaining hardware.

8) Pump the brake pedel to push the pistons into the compound and repeat the process for the other three wheels.

9) If at all possible, let everything sit overnight to let the compound dry thoroughly.

This really made a huge difference. I can still hear a bit of squeal on occasion and I have to listen closely. I've read about some other methods as well. Some owners have had good luck with using the OEM anti-squeal "spiders." They use the antisqueal compound between the spider and the pad plate. This effectively glues the spider to the back of the pad and reduces the sqeal. The downside is you have to remove the caliper to get the pad out now. There just isn't enough clearance with the rotor in there. If you're changing from street to track pads often this would probably be more pain that it's worth.

-Charles

[charlesl]

Update:

Using the anti-sqeal compound alone did not really fix the issue. I don't think they sqealed as much but it certainly wasn't what I was after.

This past weekend I tackled it again. I took the pads back out and removed all of the red anti-squeal compound and cleaned it off the pistons as well. I then cleaned and replaced the anti-squeal spiders that I'd taken out last time.

Next, I covered the back of each pad with red anti-squeal compound and let it sit for 20 minutes or so. Again, you want to get the pads back into the caliper without scraping all the compound off. Push the pistons back into the calipers with your fingers. Keep the pads against the rotors as they slide in.

This seems to have eliminated the squeal from the front brakes entirely. I can't make them squeal anymore. The rears may or may not squeal when I stop. It seems to be impossible to predict. It does help to bed the pads in thoroughly. Get the car up to 75 or so and brake HARD down to 5mph. Repeat once or twice.

I'll keep you posted...

-Charles

[clord]

Yes, please do keep us posted, Charles. If you find a solution that works.....and STAYS working..... we want to know.

[charlesl]

UPDATE:

OK, things are definitely better now. I loaned my daily driver to a friend since her car is in the shop so I've been driving the GT3 for three days now. The brake squeal is most certainly improved but not entirely gone. It is diminished to the point I can live with the car now. The final straw with me was when I stopped at a stop sign in my neighborhood and there were some people standing at the corner with their dog. Well, the brakes started howling and the dog howled right along with them... Ugh.

Anyway, here's what I believe to be the tricks to making this work:

1) Clean everything with brake cleaner. Pad backing plates, anti-squeal spiders, pistons, everything.

2) Use PLENTY of anti-sqeal compound. The instructions say cover the entire back of the pad. Do so.

3) Make sure you push the pistons all the way into the caliper before reassembly.

4) Let the compound get pretty tacky before you put it back together. I waited about 20 minutes.

5) You'll still need to bed the pads. Run up to 80mph or so and romp down on the brakes down to 5mph. Repeat at least once.

I'm looking into some EBC Green pads for this car. They reportedly dust MUCH less. If they also don't squeal as much it'll be a win all the way around. I'll update this thread again over the weekend.

Thanks!

-Charles

[charlesl]

UPDATE:

Despite all my efforts, the brake squeal is still more than I can tolerate. The brakes are quiet when I leave the house for the first few miles. After that, they start squealing again. I'm pretty sure they're squealing a lot more when they're hot. I've ordered a set of EBC Green pads for the GT3. They shipped yesterday and I'll update this thread again once they're installed.

-Charles

[charlesl]

Gang,

I've made some more progress on the brake squeal issue. Here's what I have now:

Rear Brakes

Front Brakes

I installed the brakes with the OEM anti-squeal "spiders" from Porsche.

Initial Results:

1) Brake squeal is greatly reduced and is diminishing even further. According to the pad manufacturer, the pads need a few hundred miles before fully bedding and eliminating the squeal. This is consistent with what I am experiencing. The howl I used to get from the rear brakes is completely gone. That one was the worst. I'm still getting some of the high frequency squeal at once specific point in the pedal. If I press down a touch more or a touch less, it stops.

2) Brake dusting is reduced. Hard to say by how much. I do know that I can make about twice as many trips in the car before the compulsion to clean my wheels overwhelms me.

FAQ:

Q: Are these pads OK for track use as well?

A: I don't track my car so I can't say for sure, but I really don't think so. They're specified as a street pad. If you're tracking your GT3, you probably have other pads for that anyway.

Q: Can you use the OEM brake wear sensors with these pads?

A: Yes. The EBC pads come with the notch for the sensor. I had to scrape a bit of the paint out of the notch to get them to slide in but they fit just fine.

Q: How come the DP21514 pad is listed as a "front" instead of a "rear?"

A: GT3 rear brakes are identical to front brakes on Boxsters, Caymans, and some Carreras. Porsche used the same caliper, rotor, etc. The parts sites haven't caught up on this yet.

Q: What's the black square on the back of each pad?

A: Factory anti-squal or anti-vibration padding. The OEM "spiders" may not be needed with this. I didn't try it that way.

Q: Where can I get these pads?

A: I ordered mine from AJUSA.COM but I assume other places have them. Note that I have no association with AJUSA. I'm not interested in selling brake pads. I'm interested in eliminating squeal in a GT3.

Q: Do these style pads come in any other compounds?

A: Yes. There are what they call "Yellowstuff" and "Redstuff" compounds. The redstuff are ceramic pads.

Q: Do the EBC pads "feel" any different that the stock ones?

A: I really can't tell any difference. I've tried braking easy, braking hard and I just can't feel any difference.

That's about all I can think of for now. I'll continue to post updates as these pads bed.

Thanks!

-Charles

Edited May 18, 2007 by charlesl

[damianc4s]

Did you actually buy new OEM spider shims? I've found re-using them just caused squealing. New shims have an adhesive backing that sticks to the back of the pad holding the pad firmly in place with the 2 & 3 pots. So unless you are prepared to try and apply a suitable high-temperature adhesive to the old shims just buy some new ones.

[charlesl]

Did you actually buy new OEM spider shims? I've found re-using them just caused squealing. New shims have an adhesive backing that sticks to the back of the pad holding the pad firmly in place with the 2 & 3 pots. So unless you are prepared to try and apply a suitable high-temperature adhesive to the old shims just buy some new ones.

I have new shims but they are not installed at this time. The squeal is pretty much eliminated now. Every now and then I'll get a little squeak or squeal but it's very livable now. If it gets bad again, I'll take everything out and put the new spiders in.

I'm quite convinced it was the EBC Green pads that did the trick. I talked to several mechanics and they never had any luck eliminated squeal with the OEM pads.

-Charles