Binding brake

[MrRiden]

I've got a 83 r65 in the garage with similar symptoms to this thread http://suraklyn.com/yabb/YaBB.pl?num=1217905538
It is a single Brembo caliper with all original parts. The complaint was squeaking brakes.  On removing the pads to coat them with disc brake quiet the pistons were observed to extend by themselves. They are easy to push back in but as if still under pressure they move outward again. This is with enough force to cause significant drag on the front wheel.  An inspection of the MS revealed a clogged return hole and some pitting. A new MS and hose have been ordered but...anyone else ever experience this? It's like the system self pressurizes. What was the fix?
rich

[Justin B.]

Normally cleaning out the bleed-off hole in the MC will cure this...  I have a '57 Chevy that had this problem when it still had the stock single master cylinder .  I could only get a couple of blocks before the brakes were totally locked up!

[scarygary]

Normally cleaning out the bleed-off hole in the MC will cure this...  I have a '57 Chevy that had this problem when it still had the stock single master cylinder .  I could only get a couple of blocks before the brakes were totally locked up!

I had the exact same problem on my old R100. Yes, master rebuilt kit will do the trick. My master was building up pressure and that was making the pistons grab the disk causing brake drag. To release the pressure, I had to loosen the cap. With mine, the piston was heavily corroded. It looked fine from the outside.