rbauhart

I am looking for a used set of 964 turbo / 965 rear brake calipers for my RS America. Does anyone know of a pair that is available anywhere? Or possibly a source for a good deal on a new pair?

Thanks very much if anyone could help point me in the right direction.

Roland
rbauhart@hotmail.com

Bill Verburg

What you really want are 993 rear calipers, they are correct for your 964 rear rotors(24x299) but have the same bigger(30/34) pistons as the 965 rear.

965 rear calipers will have the wrong o/s and want the wrong rotors(28x299) for your application

rbauhart

I had considered that. I have been looking at the following specs:

http://members.rennlist.com/1976c38/brakes.htm

I thought that by going to the 28mm thickness rotors, it would give better heat dissipation and better rotor durability, along with more rotor selection. I know that Steve at Rennsport recommends a 317mm Brembo rotor for the rear with the turbo calipers. What do you think? I am running Big Blacks up front on stock 322mm rotors, but will definitely be going to a 332mm slotted Alcon or AP rotor in the future, and am trying to sort out my front/rear bias issues for the track.

Any advice on Master Cylinders? I have the stock RSA MC @ 20.64mm. Worthwhile to upgrade to the turbo MC (23.81mm) or even the euro RS MC (25.4mm)? Are they easily compatible?

Thanks for any advice,

Roland

Bill Verburg

Yes thats my brake page

the issue is that the 28mm 965 rear rotors don't fit properly ona 964 w/ n/b trailing arms.

you can fit big 993tt/RS 322x28mm rotors but the parking brake won't work and the o/s is also probably wrong. Most people that want 28x322 in back use a 2 piece hat/rotor w/o a p/b

I have no experience w/ the aftermarket 28x317 rotors let alone those rotors w/ 965 rear calipers, if Steve says that they fit then I believe him, they are a great rotor for that app.

If I owned a 964 w/ a bbk, say 32x322 front then I'd do everything I could to get more rear bias, 317 and 965 rears do that.

m/c depends on whether the car has vacuum or electro-hyd boost, w/ vacuum use th 993 23.8mm m/c and associated van can. W/ electro-hyd use either 23.8 or 24.5, the bigger m/c will give you a better pedal.

rbauhart

Very good information Bill. Thanks very much.

I definitely want to be keeping my parking brake, as the car is also street driven. I will have to figure out through Steve if that 317mm rotor setup allows for the parking brake. Anybody know of a setup such as this?

Maybe the 993 rear calipers will be the best option in the end.

Roland

Bill Verburg

Thats essentiall what was used on the 964RS
32x322 w/ a version of the 993 front calipers, 993 rear calipers on 24x299 968 M030 rotors, 25.4mm hyd- boosted m/c.

I would totally remove the p/v if it were mine

rbauhart

What difference does removing the proportioning valve make?

Bill Verburg

you get more rear bias under heavy braking

rbauhart

Originally I had considered using my old stock front calipers (44/36mm pistons) for my rear brake setup, but I have heard a lot of mixed opinions.

Most people say it is too much rear bias. Some say that in the right hands for seasoned driver's, it's a great way to go.

I'm leaning towards keeping them as an option for the future, but not going that route immediately.

Bill Verburg

2 reasons not to use front in back
1) the pistons are way way too big and will give you way, way too much rear bias
2) those calipers want 28mm rotors which, as has been discussed, are hard to fit to a n/b 964

rbauhart

I agree from everything that I have heard.

So, my two rear options:

A) 965 calipers with 28mm rotors
B) 993 calipers with 24mm rotors

Priority: Keep the parking brake.

With A, parking brake is an issue. Is it the rotor specs that cause this? Maybe a custom rotor application is the solution? Maybe what Steve has suggested with the 317mm Brembo applicaiton.

With B, parking brake and stock rotors are kept, but I have heard that there will be mounting compatibility issues. Do they fit on a 964 setup? With adapters of some sort?

The 28mm rotors would also help dissipate more heat I think, which would be a benefit on the track.

rbauhart

Steve has told me that the 965 caliper/rotor application keeps the parking brake. That will be the route that I take then I think.

Bill, all your information has been really helpful. Those brake spec charts of yours are great.

Roland

Bill Verburg

Please do post pictures and report on how it's working when they are installed

rbauhart

I most definitely will. It may not be until sometime later in the season though, as I am just doing my research at the moment.

HiWind

I see the point above re 965s on the rear ...

But if I fit 965 turbo fron calipers on my early 90c2 fronts,
Can I then move the c2 fronts to the rear?
Or will the piston size problem / too much rear bias still occur?