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CB750 / CB750F1 Rear Disc Brake
« on: October 09, 2020, 11:04:02 AM »
The rear caliper piston won’t retract leading to overheating.
I’ve been on this problem for a number of days now and can’t solve the problem - help please.
I’ve tried two different rebuilt callipers.
New HEL braided oil line with new banjos. The banjo bolts are shorter than the originals.
Tried two different seal kits in the master cylinder. Now had it apart 4 times.
The return hole is clear.
The only way the pistons will push back in is by undoing the bleed valve or the banjo at the master cylinder.
The brake works releases fine by hand but if it is run up and gets hot the brake binds badly and overheats.
To be honest I can’t see how the seals in the master cylinder release the pressure when they both face the same way and the cup on the end of the spring is over the outlet hole.
I don’t know what else to try.
I also rebuilt the front brakes (twin disc conversion) and have no problem with those.
I’ve been on this problem for a number of days now and can’t solve the problem - help please.
I’ve tried two different rebuilt callipers.
New HEL braided oil line with new banjos. The banjo bolts are shorter than the originals.
Tried two different seal kits in the master cylinder. Now had it apart 4 times.
The return hole is clear.
The only way the pistons will push back in is by undoing the bleed valve or the banjo at the master cylinder.
The brake works releases fine by hand but if it is run up and gets hot the brake binds badly and overheats.
To be honest I can’t see how the seals in the master cylinder release the pressure when they both face the same way and the cup on the end of the spring is over the outlet hole.
I don’t know what else to try.
I also rebuilt the front brakes (twin disc conversion) and have no problem with those.