Have a 1939 Ford with 1970 GM disc brakes with a typical underfloor brake booster. I just bought and replaced the brake calipers from Speedway motor. I just finished bleeding the brakes took it for a test drive when I push the brakes it stops fine but when I start to drive it pulls to the left I'm constantly having to correct to go straight. Along with a nice hot brake smell . I feel like the calipers are not releasing the pressure like it should be does anyone have any tips on what I can check or try or to help diagnose if the brake booster is bad or simply an adjustment somehow.
First be sure that the M/C rod has a bit of play. If the master can't fully retract fluid will be trapped in the system and as it heats and expands will lock up the brakes. This is a not uncommon problem.
Double check the caliper slide bolts along with the anti rattle clips on the brakes pads. Seen those installed wrong on several occasions. The slides bolts should be clean with a slight coat of high temp caliper grease on them. Another thing to check which I have ran into twice in aftermarket mounts ii the gm slide bolt style was the holes were threaded at an angle. And when applying the brakes the caliper would bind on the bolts and not release... BTW the very first thing I would do, Jack up offending wheel, apply brakes several times, check to see if the wheel is locked. If it is, break the bleeder screw, does fluid squirt out ? Did the wheel become free doing this? If so do the same on the other side, is it the same ? Hard to turn then frees up once the bleeder is opened ? OK, if both sides are tight and loosen up immediately opening bleeder you have a problem upstream, master cylinder, push rod, proportioning valve etc. IF it's only one side and it frees immediately opening the bleeder valve then it's the rubber hose. Seen brand new hoses with problems before.... ....
I have had to file the pads where they fit into the caliper bracket, the new stampings have bad surfaces and notches . check that the pads move in there mounts
All right so I did some testing. Reinstalled the caliper pins made sure that there were greased and everything was smooth. I jacked up the offending wheel like you suggested cracked the bleeder screw and instantly some fluid came out and the brake let loose. I tested the other side and when the brake pedal was released I could move that wheel no problem so it looks like the issue is with only one side not releasing pressure. My question is would the problem still be Upstream if one side is working fine?
Brake hose on that side, got a flap in it working like a one way valve. Change that hose first.... ...
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