Front brake locked up

[gsa102]

So I was racing HS yesterday, and the front brakes got hot and locked up about 13 miles in (50 minutes). I smelled the brakes a couple miles before as I passed the pits. Luckily, It stopped near a group of people and someone had a wrench to let the pressure off. The pads were thin to begin with and were pretty much gone at this point.

After that, I started to avoid using the front brake. About 5 miles further they locked again, and someone was there with a multi-tool and I let the pressure off again. I got to the pits, checked for pressure, and duct-taped the wrench to the crossbar pad. On I went but avoided using the front brake. I didn't have to mess with it again for the last lap. It felt like it was dragging a little, but that might have been my butt dragging .

Anyone have this issue before with the stock brakes?

I tightened up the lever before the race and might have had it too tight. The first time I stopped, I loosened the lever back up, but then the brakes locked up again later. I am thinking the relief hole in the master cylinder is plugged up, not letting the pressure off. As soon as I let the pressure off, the calipers released, so they shouldn't be hanging up.

Any thoughts?

I will be getting a tool bag to carry some tools if I am going to race a 15 year old bike. The motor/traction was awesome but the forks were lacking.

[Julien D]

Had the same thing happen last time out. Like yours, my pads were very thin. I'm inclined to think the caliper pistons over-extended and got stuck.

[Fletch]

Air in the system? Otherwise what ^ said.

[rbates9]

I had an issue with a wrong brake lever that held the master cylinder just off it's neutral position and it made the brakes drag after just a few minuets of riding. It might be the plunger is sticking in the master cylinder and not moving out all the way.

[scheckaet]

worn pin?

[gsa102]

Had the same thing happen last time out. Like yours, my pads were very thin. I'm inclined to think the caliper pistons over-extended and got stuck.

Possible. Especially with the thin pads allowing the heat to get back to the caliper. But I wouldnt think the caliper should hold pressure unless the release path is blocked.

I'm with rbates9, thinking it is a lever/master cylinder issue. I noticed the brakes dragging a little right after I adjusted the lever up the day before the race, but didn't pay it any mind. But when I adjusted the lever back they still hung up. So it is likely the master cylinder piston.

I washed the bike last night and bled the brakes with fresh fluid. Promptly got air in them - doh. Time to get a turkey baster to reverse bleed. I am going to dissasemble them tonight and clean and push the pistons back in to make sure they are moving freely. And pads are on order.