Best Pad Set Up For 996.2 GT3 OEM Discs

[FunkyGT3]

Hi there,

i recently fitted brand new OEM discs front and rear with padgid RS 29 pads front AND rear....

and im finding the rears squeek alot. and i think the ABS is kicking in too early sometimes under heavy braking. The brakes just dont feel that great in general!

im now wondering wether the RS29 is overkill for the rear of a 996.2 GT3? and maybe thats the problem? perhaps messed up the brake bias?

any help appreciated.

[Slippydiff]

FunkyGT3 said:

Hi there,

i recently fitted brand new OEM discs front and rear with padgid RS 29 pads front AND rear....

and im finding the rears squeek alot. and i think the ABS is kicking in too early sometimes under heavy braking. The brakes just dont feel that great in general!

im now wondering wether the RS29 is overkill for the rear of a 996.2 GT3? and maybe thats the problem? perhaps messed up the brake bias?

any help appreciated.

For road use ? or road and track ? On both the occasions I've used RS29's in the rear (996 GT2 and M3 CSL) for road use only, they've squeaked horrendously. They're fine if you use them on track and get them properly hot (and bedded in) but on the road only, you'll struggle to get sufficient temperature in them to stop them from glazing and thus squealing in my experience.

From my previous thread here (10 long years ago) : https://www.pistonheads.com/gassing/topic.asp?t=44...

"As regards the brake situation I did some research on Rennlist, the results of which indicated that the 997 Turbo or 997 GT3 steel rear discs were 350mm diameter and would thus be a straight swap for the unserviceable PCCBs on the rear of the car.
The company that had previously supplied me with the Alcon discs told me the steel conversion was fully compatible with the original PCCBs on the rear. (subsequent conversations with various other specialists would tend to indicate this isn’t the case)

Andy suggested the use of Pagid RS 29 pads front and rear as he felt the aggressively hooked Alcon discs were not readily compatible with the standard OPC GT3 P90 pads.

A couple of weeks later I found myself back at Silverstone for the fitment of the steel 997 Turbo rear brake discs, replacement RS29 pads all round, and the fitment of the Cup toe links along with a complete geometry set up.

After a lot of hard work by Andy and his lads (and numerous cups of Doms quite frankly horrendous coffee!!) the car was ready to be road tested.

Andy came back and professed himself pleased with the results of the Cup toe links and the geometry adjustment, corner weight and ride hight adjustment but also pointed out he thought that the car was pulling to the N/S and was thus in need of further investigation.

Whilst road testing the car Andy had bedded the brake pads in but felt that there was an issue with one of the calipers binding on the front of the car.

Andys investigation revealed that when I’d removed the discs and pads to de-glaze them some weeks earlier I’d installed one of the alloy caliper spacers (supplied with the conversion kit to space the caliper out to accept the 12mm larger diameter disc) the wrong way round.
This meant the corner of the spacer was sticking out and wasn’t allowing the pads to sit squarely in the caliper body. This in turn was making the new (and thus thicker) pads bind against the disc.

Clearly I have to accept the blame for this oversight BUT more worryingly we found the Alcon disc/bell set up on the same side was not running centrally to the caliper itself. At the thick end of £1200 for the disc conversion, I’d expected better.
This meant however that the space on one side of the disc was only just sufficient to get the pad in (but did not leave sufficient space for the expensive anti squeal shims to fit between the caliper pistons and the back of the pad)


Sure enough as the journey home progressed, the dreaded RS29 pad squeal started to manifest itself…………………..

By the time I arrived home some 100 miles later, the noise was embarrassingly loud.

There then followed numerous attempts by myself over the following weeks to silence the squealing.
Firstly by bedding the pads in as detailed precisely on the Pagid website, and then removing them and applying a chamfer to the leading edge of all the pads.
The results appeared successful at first, but after a few heavy stops the squeal re-appeared with a vengeance.

After speaking to the UK agent for Pagid I decided to have some dampers made up for the pads to reduce any resonance that may have been causing the pads to resonate and thus squeal (the dampers are fitted to the standard GT3 P90 OPC pads and take the form of round steel weights attached to the brake pad)

The fitment of these dampers again seemed successful at first, but as before, and after a few heavy stops, the squeal re-appeared.

I then read on Rennlist that the RS29s could be silenced by heavy heat cycling.
I therefore took the car out to my favorite section of road and drove it as if I’d just stolen it.!!

In the process I managed to make the brakes fade to point whereby they wouldn’t stop the car………………….
Sure enough the squeaking stopped thereafter…………………………….but only for a few days.

Whilst sitting and pondering the problem one evening I decided I needed to establish just where the squeal was coming from, ie the front or the rear brakes.

Next day saw me on a deserted road driving the car along at 50mph with the door open and my head stuck out of the door down by the sill listening for the source of the squeal !!!!!!!

My investigation revealed that the front brakes were now totally silent and the rears were the source of the noise.

Having established this I conducted further tests to establish under which circumstances the brakes squealed.

From high speeds and using a heavy (race type) “prod” of the brake pedal, the squeal was not present. If however one braked gently from high speed and reduced the braking pressure as the car slowed, the rear brakes squealed every time.

Logic indicated that the front brakes were clearly doing the majority of the work to slow the car and thus the rear pads weren’t operating at a temperature consistent with preventing them from glazing up and squealing.

A chat with the American supplier of the RS29 pads revealed that the four pot 996 GT2 rear calipers utilize the same brake pad shape and thickness as the 996 Turbo rear caliper (this despite the GT2 rear disc being 350mm in dia as opposed to the Turbos 330mm dia) it also transpired that the pad is the same as those fitted in the front caliper of the 996 C4 or C2

I duly purchased a set of standard off the shelf OPC 996 Turbo pads and installed them with yet another set of new (and expensive) anti squeal shims.

Result ? no squealing brakes !!!"

[FunkyGT3]

Slippydiff said:

For road use ? or road and track ? On both the occasions I've used RS29's in the rear (996 GT2 and M3 CSL) for road use only, they've squeaked horrendously. They're fine if you use them on track and get them properly hot (and bedded in) but on the road only, you'll struggle to get sufficient temperature in them to stop them from glazing and thus squealing in my experience.

its only been road use since i fitted the new discs and pads.

i do maybe 3 track days a year. I have Spa and the ring this summer then the rest of it is fast road use.

should i stick a stock pad back in the rear? or a RS14?

[Slippydiff]

If they're not already badly glazed I'd pull them out and fit standard rear pads.
When you're ready to track the car, I'd drop the RS29's back in and see if you can bed then in on the track day.
The decent heat cycling of a trackday should enable them to be bedded in properly, and if you're lucky they won't squeal on the road afterwards.

[FunkyGT3]

Slippydiff said:

If they're not already badly glazed I'd pull them out and fit standard rear pads.
When you're ready to track the car, I'd drop the RS29's back in and see if you can bed then in on the track day.
The decent heat cycling of a trackday should enable them to be bedded in properly, and if you're lucky they won't squeal on the road afterwards.

ill maybe just stick stock rears back in and leave them.

im not exactly a track slag. only do 2 or 3 maybe a year. rest is fast road use.

Im sure i read someone said put RS14'S on the rear?

[Cheburator mk2]

That's what I have in my 996.1 which has been converted to 996.2 setup. RS29 and RS14 at the back. Works brilliantly for both track and fast road - car gets heavily used for two/three Ring trips and two/three Bedfords per year. No squeal either.