When you apply the brakes pressure is applied to the caliper when you let off the brake pressure is relieved to the caliper. If the caliper is stuck it is stuck until you manually pry the piston back into the caliper. the next time you hit the brakes it will lock. The brake line could have collapsed inside, you won't see that on the exterior. If at that point you break loose the banjo fitting at the caliper and there is pressure it could be a collapsed line. The last thing is if you have no play between brake pedal rod and master cylinder the brakes will seem ok until the brake fluid heats up and expands which will apply the brakes due to the fluid expansion. You should have some play in the pedal to where the pedal will move slightly before activating the master cylinder.
|