Has anyone had this happen?--rear brake gets progressively tighter as the bike gets warmer,and finally, the pads sieze against the rotor. I pull over (hopefully without getting creamed from behind) and bleed some fluid out, and I am on my way until it happens again. I keep bleeding fluid out until it must be almost empty, and it keeps happening!! I have verified I have the right fluid (DOT 4) and I have bled the system at least twice and completely replaced all the fluid. What the hell?

 

if the pistons in the calipers get a little rough spot on them they won't retract. you might need new pistons and o-rings to fix it. harley has replacement pistons.

 

thanks for the input. I will check out the pistons. If that is not it, is it time for a new caliper or is there another suspect. I gotta get this fixed. It especially sucks when I am in the middle lane of the freeway and it freezes up at 70 mph. yikes!

 

Do not know how many times I tell you members to clean them. I put my procedure on my web site in PDF form so you can do it yourself. I have never had caliper problems, maybe because I do my own maintenance. I will not be the one whose brakes lock up, will all of you?

 

Had that happen to me with the front. It was the Master Cylinder. Replaced it and all was fine.

 

This question was asked in a recent edition of Cycle World. The response was long and involved explaining how the brake fluid moves, builds, and releases pressure. The editor first apologized if it wasn't the problem, but he also wrote about seeing cases in which the rider was unknowingly putting pressure, it doesn't take much, on the brake pedal while riding.

This would be enough to block the small hole that allows fluid to return to the reservior and would cause a build up of pressure in the caliper. Eventually this would build up enough to lock the brake. That would explain why your brake gets better after you remove enough fluid to release pressure.

The editor also went on to say that if the rider wasn't the cause of the problem that the caliper would probably have to be rebuilt. He also suggested that the person asking the question should try riding without touching the rear brake at all to check if that was the cause.

Ron

 

Great how to article below for cleaning the brakes to eliminate the problems. The retraction of the pistons into the calipers is very important and should be done with the shoe lace after spraying some brake cleaner in the area so that the brakes do not hang up and wear prematurely.

http://www.lyndallracingbrakes.com/service_tech.htm

 

thanks for all the input. this weekend, I am tearing that caliper apart! attached is a photo of the offending party-------

 

Nice Ride. Did you make any changes to the rear brake system recently?

 

Hope you solved the problem. Sounds more like a MC, but certainly could be sticking caliper pistons. The reason I think it is more MC related is that when you bleed the fluid out...the caliper pistons must be retracting if it temporarily clears the problem. This does not sound like a sticking caliper piston. You could even have some trash somewhere in the circuit also. The MC will force fluid past the blockage but the fluid won't return under relaxed line pressure.

What did you find out?