RS2 Brake Deciphering

[LGK6D]

I'm after a bit of advice, I've only had my car since November and I'm still getting to know it a bit really.

I'm sure there must be something wrong with the brakes. To put it bluntly they're a bit ****. They feel very under powered, there's a lot of pedal travel and loads of squealing and even a bit of wobbly feedback at higher speed through the steering, pretty rubbish all round. I used to drive my girlfriends 993 a fair bit which I think has a similar set up, but never had these sort of problems. All the magazine articles of the time raved about the brakes, it can't be right.

The car came to me with new discs and pads all round, new brake fluid, all seemed well. They disks can't be warped because I've never had them hot enough and there's loads of meat on them as they're new.

I've read a bit about an optional big brake kit, which seems to have a floating calliper and bigger disc. What are the chances that the wrong parts have been fitted and how can I tell what is fitted and what should have been fitted?

Any help would be greatly appreciated.

Cheers
David

[s2driveruk]

not owning an RS2 i can only give a few pointers but check:

- they have been bled properly or start again and do it yourself or get someone local to do it for you. the brembos do take a decent bleed to liberate them of air
- check that the pad carrier plates are not crusty and corroded as they impede the pad movement or release and they then drag causing squeels and vibrations
- check the pads are seated correctly and the retainer is in properly and square to the pads
- check that all pistons can move freely
- check that the anti-squeel shims/pack backing shims or in place

Finally check that the hub is free from corrosion to ensure the disc sits square there too...


Hope that helps
David

[Ross]

The 'big brake' upgrade uses a 322mm drilled front disc vs the 304mm up front, and a larger caliper. The rear calipers are the same but it uses a matching drilled rear disc (299mm). I would imagine it to feel very similar to the 993 of the time, seeing as the fronts are effectively the same (on the big brake upgrade at least).

Mine take alot to get going, but when they bite they bite, probably a combination of all 4 dics being pretty much 'end of life' and Ferodo 2500 pads which seem to perform alot better with a bit of heat.

From the cars with standard brakes I drove, those with decent material still felt great. I would suggest it's worth checking everything out as per David's post and check for OEM or equivalent parts too. Also - the split calipers do suffer from corrosion and seem to need a refurb after about 10 years to get them working properly. On a plus, the disc are a hell of a lot cheaper on the standard set up.

[Jamo]

I wouldn't go the big brake route waste of time
Go gt3 with gt3 330mm discs
Monoblock calipers so no corrosion issues

[LGK6D]

Thanks for your responses.

The 'big brake' upgrade uses a 322mm drilled front disc vs the 304mm up front, and a larger caliper. The rear calipers are the same but it uses a matching drilled rear disc (299mm). I would imagine it to feel very similar to the 993 of the time, seeing as the fronts are effectively the same (on the big brake upgrade at least).

So chances are they are the regular RS2 Small Reds as the discs are solids. Is the Big Reds calliper from a 993 Turbo? The Small Red callipers are from 968CS? I was worried that it'd had the big callipers and small discs fitted, but I guess this isn't possible?

I will get it stripped down and see what's going on, I suspect cheap pads too possibly.

I've read a bit about the GT3 brakes, but the car is pretty stock and this upgrade/modification path looks like a pretty slippery slope to get started on

[jade]

In regards to poor bite and wheel whobble, this could be related to the P/S, brake pump I have been having a simular problem, When hard braking at speed do you hear the pump working ?

[bilko0795]

Just done the GT3 upgrade on my S2 get all the gear together and 2 hours later bingo
all done. thats with everything coming off ok no seized nuts or brake lines. and the brakes now actually the car> it was worth all the hassle of waiting for all the parts to arrive. Well happy:

[LGK6D]

In regards to poor bite and wheel whobble, this could be related to the P/S, brake pump I have been having a simular problem, When hard braking at speed do you hear the pump working ?

I can't say I've noticed any pump noise. How loud are we talking?

The problem with fitting the GT3 brakes is the car will fall into the "modified" bracket. Everyone who has seen the car has said because its such a nice one, don't modify it. Once the brakes have been improved, I'm worried it might feel like it needs more power and then it'll never stop!

This is such a great forum with tons of info, you start thinking well I'll just do that while I'm doing that, and that needs doing so I might as well do this. Next minute, 500hp monster and fully modified car!

[DJones]

I can't say I've noticed any pump noise. How loud are we talking?

The problem with fitting the GT3 brakes is the car will fall into the "modified" bracket. Everyone who has seen the car has said because its such a nice one, don't modify it. Once the brakes have been improved, I'm worried it might feel like it needs more power and then it'll never stop!

This is such a great forum with tons of info, you start thinking well I'll just do that while I'm doing that, and that needs doing so I might as well do this. Next minute, 500hp monster and fully modified car!

Lol, you will end up there.... give it time...

[scillyisles]

Ok.
I have not done the Gt3 upgrade so cannot comment on it.
My car came originally with the standard brakes on it and they were fine for normal road use but when I did a track day at Brands Hatch - I did get fade.
The standard brakes corrode and replacements are costly. When you look at the costs, it makes sense to upgrade to the big reds (993 Turbo brakes) Audi do a kit which includes bigger 322mm front cross drilled discs with bigger calipers plus a matching 299mm cross drilled brake for the rear. They work very well and fit with no issues.
You should have more or less immediate bite and very good stopping power. My suspicion for your car is that your brake bomb is not working properly or your master cylinder is defective. The wheel wobble could be one of a number of things - corrosion on the pad shims e.t.c.
I have only had it once and in my case it was uneven tyres (Bridgestone) which wobbled under braking. I think I have seen other instances of this on forums.

[dobbin]

rs2 brakes

i have just refurbed my std rs2 calipers and new discs with ds2500 brake pads ,
excellent pads and for normal/fast road driving with oem look thats all you need to do.
as post above check calipers mine were rubbish before as well . also i put lockhead brake fluid higher spec to stop brake fade

[prj]

This is such a great forum with tons of info, you start thinking well I'll just do that while I'm doing that, and that needs doing so I might as well do this. Next minute, 500hp monster and fully modified car!

You need some mapping to go with that?

[LGK6D]

Ok.
I have not done the Gt3 upgrade so cannot comment on it.
My car came originally with the standard brakes on it and they were fine for normal road use but when I did a track day at Brands Hatch - I did get fade.
The standard brakes corrode and replacements are costly. When you look at the costs, it makes sense to upgrade to the big reds (993 Turbo brakes) Audi do a kit which includes bigger 322mm front cross drilled discs with bigger calipers plus a matching 299mm cross drilled brake for the rear. They work very well and fit with no issues.
You should have more or less immediate bite and very good stopping power. My suspicion for your car is that your brake bomb is not working properly or your master cylinder is defective. The wheel wobble could be one of a number of things - corrosion on the pad shims e.t.c.
I have only had it once and in my case it was uneven tyres (Bridgestone) which wobbled under braking. I think I have seen other instances of this on forums.

I'm going to strip the front callipers out at the weekend and just have a look at what has been fitted and what's going on in there. It certainly doesn't have any initial bite. Is the brake bomb part of the servo assistance on the brakes, how do I check it and where does it live?

I may look at the 993 Turbo upgrade at some point as it sounds quite sensible and was a period option it won't hurt the originality of the car. And so it begins, hmm brake callipers while I'm doing that braided flexible lines and we're off!

Thanks for all the feedback

[LGK6D]

Right then, todays findings.

I read up and did the brake bomb test which took loads of pumps so no problems there. Although I did have some pedal travel (maybe an inch) which would suggest I'm compressing air in the system which is obviously effecting the initial bite.

Now to the callipers. They were so full or road grime, brake dust and general road crap it took almost 40 minutes to get the inboard pad out on each side. They were filthy, so much so that the inboard pad was glazed, the groove was full of poo and it doesn't look like it's been working much at all. With it being a fixed calliper, this obviously has a pretty major effect. To add insult to injury the pads were fitted almost dry, there was a tiny trace of copper slip, but you'd have thought it was gold dust from what I found. There were none of those shaped anti squeal pads/shims in there either, so should I get some on order?

The pads are Ferodo and say FD5560 and some other codes. I guessing these aren't the good ones? I've cleaned and re-fitted the now filed pads and it's already made a big difference now that the pads can slide on the stainless shoulders. I've still got the bleeding to do which is my next job.

One other quick question, I've been using my winter wheels and tyres (Porsche Design 90's). It looks like these wouldn't fit with the 322mm discs and bigger callipers, anyone know for sure?

Thanks
David