Hey guys hope all is well! I have spent most of the day trying multiple things on my rear brake system on my 1980 XS650SG and have had no luck. I have recently purchased a new rear master cylinder from mikesxs and I am still having the same issue. There are no brake oil leaks and I can't get it to fully bleed even with a speed brake bleeder. Any suggestions? Ways I have tried to bleed the rear brake: - speed pump - regularly - replace master cylinder Every way I have tried there still hasn't been any leaks or pressure to the master cylinder. Could a piston be stuck or is the problem in the brake caliper. Any help would be appreciated.