Motorcycle Repair: Harley front brake problem, silicone oil, fxstc

Question
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Thanks, I still am concerned, because there is pressure behind the puck.  If if is sticking you would think that there would be no pressure pushing against it.  When I release the pressure, it retracts and works OK until the brakes are used again.  Is there a possiblility that the plunger in the master cylinder is sticking?
Thanks again for any advice,
Tim
Followup To
Question -
I just purchased a 91 Harley FXSTC and have a problem with the front brake.  The brake lever seems to pump correctly but over time pressure builds and self applies the brakes.  I have had to stop and release pressure from the bleeder to continue riding.  As the brakes heat, it gets worse.  It appears that the master cylinder can retract enough to pump fluid forward, but will not allow the fluid to return.  The system has DOT 5 Silicone oil.  I am not sure if the unit is factory or aftermarket.


Answer -
Your problem is probably the puck in the caliber is sticking. you need to remove the caliber and take it apart. In it you will find a puck that moves back and forth from the pressure of the brake fluid. Over time the brake fluid gets sticky and dirty and makes it stick. Remove the puck and clean it with brake cleaner. you then need to purchace a rebuild kit for the caliber. Drain the fluid out and install new Dot-5 fluid.
Good luck and happy riding
Mike

Answer
Generally, when you have this problem its the puck sticking. So I would check it first. If you are still having the problem you can remove the internals of the master cylinder and check it, but you vary rarely see it stick.
Good luck and happy riding
Mike