79/80 CBX Brake binding

[Write2paul]

Last year I rebuilt the front calipers on my 79/80 CBX -- not with new parts, just a thorough cleaning and reassembly of what was there.



Now, a year later, I took the bike for its first post-rebuild ride and the front brakes worked fine initially, then started dragging and --finally -- locked up completely.



I loosened the bleed screws slightly and fluid squirted out under pressure. That allowed the caliper pistons to retract enough to get me home, but now I need to do the job right.



What would prevent those brake pads from retracting properly??









-- PW

[Jeff Bennetts]

During your cleaning you have dislodged some of the crystal like substance that forms in the system, a piece has now found its way to the master cylinder and plugged the return hole in the M/C reservoir. take a very fine wire (i use different size guitar strings) to dislodge the blockage and flush your system with fresh fluid.



jeff

[busaboy]

Also, check to ensure the rubber lines have not swollen internally - the fluid can be squeezed through into the caliper because of the extreme pressure from the master cylinder, but the tiny return pressure from the caliper once the lever is released isn't enough to get the fluid back out.

[jetdoc]

I went to move my CBX over the winter and the brakes were locked up tighter than Dicks hatband. I had to remove all of the pads.



I am just now cking into what caused it.

[busaboy]

Like mine, the piston seals have probably welded themselves to the caliper bores...