Brake upgrade

My 964

Running reports
Intro
Report 1 (Fall 2001)
Report 2 (Spring 2002)
Report 3 (Fall 2002)
Report 4 (Spring 2003)
Report 5 (Fall 2003)
Report 6 (Summer 2005)

Trip reports
Intro
Lelystad (15-4-2002)
Zandvoort (25-4-2002)
Stelvio (July 2004)
LiÃ¨ge (27-11-2004)
Rennlist North Wales Run (15-7-2007)

Ring trips
June 2002
July 2002
August 2002
Swedish Weekend 2002
November 2002
April 2003
Easter 2003
May 2003
May 2003
June 2003
August 2003
September 2003
April 2004
September 2004
March 2005
May 2005

964 Reviews
Intro
1990
1991
1992
1993
2001
2002
2003
2004

Reviews of other Porsches
Intro
1993
1996
1997
1998
1999
2000
2001
2002

Miscellaneous
964 Links
Sport Auto tyre test
My personal homepage
Site stats *

Links marked with a * require a password.

Brake issues

Porsche is known for equipping their cars with excellent brakes. However, "excellent" for one purpose might not be "excellent" for another. And this is the case for the 1990 and 1991 model years: overwhelming their brakes on open roads would take quite a bit of hooliganism. Even better, their brakes cope reasonably well with your average track. However, their are two issues:

The standard brakes don't like the Nordschleife of the Nürburgring;
Their are no after-market brake pads available that fit the rear calipers.

For most people, issue number one will not be a big deal: they don't go there. Or if they do, they don't go there in a Carrera 2; they use an RS or a GT3. However, I can't afford an RS or a GT3, and I still like to drive on the Nordschleife.

Issue number two comes into play when you want to track your car. The OEM street pads are very good: they are quiet, their response is the same over a wide range of brake pad temperatures, they don't genererate too much brake dust, and they slow you down quite nicely. However, street pads are a compromise. If you accept squealing and/or brake dust and/or a non-linear response for differing brake pad temperatures, you can get better pads.

Unfortunately, the 1990 and 1991 model year 964s have a small rear caliper. The 1992 and later (and the C4 for that matter) models have rear calipers that take the same size brake pads as the front calipers. Which means that there's an abundance of after-market performance brake pads available for them.

Options

After a somewhat costly confrontation with the limitations of the standard brake system, I decided an upgrade was in order. Preferably one that didn't break the bank, because then it would be much wiser to buy another car altogether. There are lots of different options to upgrade brakes. As there are websites with much better information on brakes I'll name just a few, and refer you to Bill Verburg's excellent collection of Porsche brake info.

Here are the options that I looked at:

Big Reds in front and 993 calipers in the rear
964 RS brakes front and rear
upgrade the rears to 1992 and later specification

Interlude: Brake ducting

Regardless of the brakes themselves, something that nearly always works well is forcing more cool air past the brake discs. Unfortunately this is not so easily accomplished in a 964: its slippery shape doesn't provide many natural places to add a brake duct. The easiest place would be where the fog lights are, but then you lose the fog lights. I decided I wanted to keep the fog lights, not because I drive the 964 in fog so much, but because they're very useful to complement the normal lights when driving on narrow roads in the dark. They're also useful when doing a nightly high-speed run on the German Autobahns.

Apart from the fog light issue, routing the cool air from the fog light location to the eye of the brake disc isn't entirely straightforward. All in all I decided to give brake ducts a miss for now.

Decision time

Big Reds are nice. In fact, they're very nice. However, they're also very expensive. Too expensive for me. Not to mention that you'd need to replace the master cylinder too. And that there's no drop-in replacement available for the master cylinder...

964 RS brakes are nice too. Again, they're expensive. Not as expensive as Big Reds, but still a lot of money.

Upgrading the rears is the "cheapest" option, and in combination with a more track-oriented pad should suffice to meet my needs. Also, if I would want even bigger brakes, it would be possible to retain the upgraded rear brakes. This made the decision easy: upgrading the rear brakes to 1992 and later spec was the way to go. I made an appointment with Kaul & Will to get the work done.

The Upgrade

The actual upgrade was done very quickly by Herr Kaul himself working on the front, and a mechanic and a mechanic-in-training working on the rear. In short order the car was up in the air with the wheels off. The brake discs were removed next. The front discs were completely worn, but the rears were still in decent condition. I'll probably put them back on when these shiny new discs are worn, but for now I decided to give Kaul & Will a free hand.

The brake pads were next on the list: both the front and rear pads were due for renewal, making the hit to my wallet a bit easier to digest. Thanks to the bigger rear calipers the pads could now be replaced by more track-oriented pads (Pagid Orange).

To maintain a correct balance between the front and rear brakes, the original 45-bar brake proportioning valve was replaced by the 55-bar version that's standard in the 1992 and later cars.