After making my rear discs, I decided that it would be a good idea so upgrade my master cylinder to one which pushed more fluid. This was because the calipers I chose have quite a large diameter (43mm). This suits my application as being a Baja I have huge rear wheels. In fact I have a TON of grip at the rear, so I also changed the bias of my brakes to the rear.

1. I did a lot of research into what master cylinders would fit a beetle, and what sizes they were. I also researched what bore calipers, or slave cylinders, they were used with. (See tables at the bottom of this page.)

In the end I chose a Porsche 944 master cylinder (aka MC). This gave me separate 23mm and 19mm bores. This enabled me to push more fluid to the large rear calipers I had chosen, and also to bias my brakes to the rear.

2. The 944 MC is aluminium. It has two outputs from the 23mm section, and one output from the 19mm section. It can be connected to the stock Type 1 dual circuit reservoir with the same plastic connectors and tubing. The bolt spacing is the same as on a stock Type 1 MC.

3. The 944 MC fits in the same hole as the Type 1 MC came out of. It doesn't have captive nuts though, so you need to use additional nuts and longer bolts. The stock Type 1 push rod will work with the 944 MC, but you will need to shorten it. I shortened mine by 1cm and it feels good to me. :-)

4. On the two 23mm outputs I connected the brake light switch, and the hard line that runs to the rear brakes. I ran the 19mm output to a T-piece, and then to the two front calipers.

If you were keeping your brakes biased to the front you would run your front brakes from the two 23mm outputs, and your rear brakes from the 19mm output. You'd need to add a T-piece to the rear hardline for the brake light switch.

It works REALLY well with the whole brake system I have created, and I'm extremely pleased with it. My Baja stops very quickly in the wet or the dry. I can't get the brakes to lock in the dry. In the wet if I really stamp on the brakes I can get the rear wheels to lock first. However if you are expecting this it's not a problem.

Please note that this setup works for me, but it might not work for you. Unless you are copying my entire brake system, and are running it on a Baja, then you will probably need to do things differently. My solution is just an option, and coupled with the information below, should help you decide with MC would suit your application. When you do fit the MC of your choice be sure to test it thoroughly so that you know how your brake system will work in all conditions.

IMPORTANT: Messing with your brake system could be dangerous, so think carefully before making any changes to a working system.

The information I used to choose my replacement Master Cylinder:

If you feel like filling in any blanks please e-mail me the information. :-)

Log:
Porsche 944 master cylinder fitted: May 2003