Which 7/8 master cylinder?
Thanks everyone for the replies. Any more info on Cass's contact? Dont know exactly whats going on but along with the car stopping slow the calipers right now are locked??? Any ideas?
Locked brakes and non-returning pedal is fluid not returning into the reservoir, usually a bad hose..... But
did you pull the residual valve out of the port that goes to the front brakes?If no, then do you recall seeing it in there? If no, did you look? If no, then NOW would be the time to check for it and remove or defeat it..
But If yes,you're sure it's not in there, then;
1) pump the pedal a couple of times then crack the lines at the M/C. If you find pressure there, and the brakes unlock, then the problem is inside the M/C, or the pushrod is too long, blocking the compensating port, or that pesky R-valve .To figure out which, pump the brakes back up, then loosen the M/C from it's mounts, and pull it away from home. If that releases the brakes, then shorten the pushrod.(EDIT;This relaxes the pushrod, and allows the internal spring inside the M/C to push the piston back into the parked position, and that opens the C-port, and that allows the fluid to return, unlocking the brakes.)
2) But if you do not find pressure at the M/C, then
Find out which wheel(s) is/are locked, and crack the bleeder(s),there. If you find pressure in one caliper it's probably a bad hose. If you find pressure in two calipers, it's probably further up the line...... like a residual valve that's not supposed to be on a disc-brake line, or a defective Combination valve but I can't imagine that.
If only the backs are dragging/locked, It's probably a hose, or I suppose a bad Proportioning-valve. But that too would be very rare.
