3 replies to this topic

[CdnAustinAmerica]

Just wanted to double check - my car has the GMC159/160 style master cylinder (large round cap, dual circuit) and it holds pressure just fine. 

Going to convert to the smaller disc brakes (keeping 10" wheels) and I just wanted to double check that it is okay for front discs, I know there are some issues with certain master cylinders having the wrong pressure, if I had to change out the master cylinder that would mean re-doing all my hard lines as the new masters are metric thread.

1976 Canadian 1000, believe its the front rear split. The wheels are older reconditioned 5.5(?)x10 "minilights" if that matters

Edited by CdnAustinAmerica, 12 December 2024 - 03:46 AM.

[croc7]

You did not say what disc brakes are now installed, “going to convert to the smaller disc brakes”. I’ve had that master cylinder on my car with 7.5” cooper s disc brakes for 20 years with no problems.

[CdnAustinAmerica]

You did not say what disc brakes are now installed, “going to convert to the smaller disc brakes”. I’ve had that master cylinder on my car with 7.5” cooper s disc brakes for 20 years with no problems.

Converting from front drums, thanks for the info though. I also learned that apparently these were originally fitted to works cars? Is that true?

Edited by CdnAustinAmerica, 27 December 2024 - 09:47 PM.

[Spider]

Converting from front drums, thanks for the info though. I also learned that apparently these were originally fitted to works cars? Is that true?

 

The GMC159 (Front / Rear Spit) was part of the kit that was offered through Special Tuning for fitting to all Minis including the Cooper, Cooper S and 1275GT cars, all of which had disc brakes.

 

There's various notes with the GMC159 and GMC160 master cylinders that front and rear need to be bled together. As best as I have been able to determine, that was in fact only the case when the PDWA Valve was fitted with the GMC159. By bleeding front and rear at the same time, it was to prevent the switch in this PDWA Valve from tripping. Should that occur, they can easily be reset. I see no reason in the world why the GMC160 can't be bled in a conventional manner of one wheel at a time.