Rebuilding Brake Master Cylinder an Impossibility?

[Pancho]

Have a tandem brake MC on my 71 MGBGT. Can't get the damned thing apart. I'm at the point of pulling the piston out of the bore but the white nylon washer will not budge! Yes, I removed the snap ring. I seem to remember someone advising against trying a rebuild, maybe this is why. Anybody with experience on these units?

 

[Banjo]

That washer's a pain... And it dosen't come in the rebuild kit ( I found out after drilling it up to get it out) I luckily has another master to rob it from.
It's been just long enough I can't rember any tricks, but it can be done.
I use WD40 on my small hone to clean up the bore, but be ready to have it resleeved if there is ANY pitting to the bore. You don't want to fool around with a possible brake failure.

 

[Mickey Richaud]

Pancho -

I gave up on mine, and opted for a new one. Probably money well spent in the long run, but didn't do much for my ego!
If I ever learn the "secret handshake" I'll give rebuilding it another try to have on hand as a spare.

Mickey

 

[mgbmedic]

it's been awile, but i remember using my air compressor to the brakeline connection and it may force it out, just be sure you have all the snap rings out first

 

[trrdster2000]

Re: Rebuilding Brake Master Cylinder an Impossibil

Done a lot of these back when and had to drill out the spacer, but the spacer was always in the kit. You might try your NAPA dealer and give him these numbers NAPA United 1035 and see if he can find a few kits laying around. After the spacer you will find there is another C clip down in the cylinder, buy a cheep pair of needle nose and grind them down thin enough to fit and file a little 45 degree angle on the bottom, both sides, this will help hold the clip. Good luck, Wayne

 

[Pancho]

Re: Rebuilding Brake Master Cylinder an Impossibil

Wayne, you're right. I drilled out the white spacer, carefully, because there's a rubber cup under it. Got the snap ring out and from there on it was straightforward. The kit I got from NAPA was a repackaged Australian-made kit from PBR International. It had the white washer in it. The metal washers that go behind the cups did not fit however so I reused the ones that were in it. The only other thing to watch out for is to support the spring-loaded plunger somehow while driving out the roll pin. You don't want to bend the thin metal rod that the two spring-loaded pieces slide on. If I had deep pockets I would have given up but "poor people have poor ways", as my grandmother always said. Lack of money made me think and ask and learn and eventually prevail. A day of your life is wasted if you don't learn something new that day. That's what I tell my students; and I believe it.