View Full Version : Mk 1 Brake Booster

Bruce Bowker
07-13-2004, 05:59 PM
I have a MK 1 Cooper S 1967. It has been changed to a dual master cylinder since I feel safer that way.

I was going to have the Mk 1 brake servo (booster) rebuilt but was told it was better to use the older booster/servo style with the single master cycliner (original style) unit. Is there a reason that the Mk 1 servo can not be used with a newer style dual master cylinder? I prefer not to use the newer style servo.

Thanks for any input.


07-14-2004, 12:12 AM

After I read your post, I went over to my friend's repair shop where he was fixing (what else?) a Mini. He and I talked about this question. The only thing either of us could think of was that the Mk.1 Minis used self energizing front drum brakes that do not need as much "assist" as the front disks on newer cars......so maybe the old-style booster would not "help" enough with newer disk brakes. According to MiniMania, the newer Mk 3 booster will fit all Minis, so I would guess that it would work the other way around (old booster on newer master cylinder)......but maybe with less assist. Info from MiniMania here:


Bruce Bowker
07-14-2004, 04:47 PM
Thanks for your thoughts. I do have the original Cooper S disk brakes on front and Cooper S drums rear. Car is a 1967 Cooper S. The only change I have made is the installing a dual master cylinder instead of the original single master cylinder. Everything else is the same.

My question is will the original booster work with dual master cycliner. I was told it was better to use the newer style booster which I would prefer not to do.

Brakes have not from the first day I had the car even after rebuilding the entire system (but not the old style booster) lock. They stop the car OK but I can not get the wheels to lock up.

I think I may rebuild the booster anyhow and see what happens. Can't do any harm for sure.

Thanks again