# How to tell bore size on master cylinder?



## machschnell (Mar 21, 2000)

I purchased an 85 Golf with what appears to be a Bendix master cylinder designed for an A2, which would be a 20mm bore. However the calipers and rotors are upgraded from a Mk3 GTI, I believe they are Girling 60s. Anyhow, their is alot of brake pedal travel and stopping power are not what I would expect they should be (compared to my former Mk3 VR6 and current Rabbit GTI) and I'm thinking that the small master cylinder is the issue. I've bled the system already so I know that's not the issue. And I haven't double-checked what pads are being used. Rotors are cross-drilled. 

The MC is branded Bendix with a part # (though hard to read) of 375140. I've contacted Bendix to see what they say. 

Any way to tell what bore size an MC has either on the car or off the car? 

Any help appreciated, 
Thanks :thumbup:


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## GTijoejoe (Oct 6, 2001)

MC size should be stamped on the body of the housing, if it is not than measuring the piston diameter is the only other way to know for sure without contacting the supplier.


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## DAVEG (Aug 14, 2001)

Joe do you think a 22mm master cylinder is needed for the F10.1" X R9.4 disk brake conversion for the early GTI? I am in the process of doing this conversion and want to have the proper parts. I also will want the Scirroco proportioning valve...yes?


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