Motorcycle Repair: Stuck front brake, brake caliper piston, piston seals

Question
I have a 84 VT 700 Shadow and my front brack is stuck, the bike won't move forward even with power but I can push it backwards.  I rode the bike about 1 block and then it wouldn't move.  Thank you, Jim

Answer
Jim, one or two things have happened to your bike's braking system.

1. The small bleed hole in the floor of the master cylinder is plugged up, not allowing the fluid pressure to release. There are two separate holes in the master cylinder floor.. one allows fluid to be drawn into the system and the forward one is pressure release.

AND/OR

2. The brake caliper piston seals have expanded in their grooves, due to corrosion build-up in the seal ring grooves. This causes the seal rings to grip the pistons rather than allowing them to slide back and forth.

After 28 years, a good cleaning and overhaul of the master cylinder and caliper is in order.

If you hit the caliper on the side with a soft faced mallet, it might back the pistons off a little to allow you to roll the bike to safety. Or you can try releasing the fluid pressure with the bleed nut on top of the caliper.

Bill Silver