Fix for a stuck piston in brake caliper?

[Mazz]

Noticed this while going over the sled today, the outside set of pistons in the caliper are not moving or moving very little while braking. The disk is actually rubbing slightly on the side of the caliper. I haven't noticed it while riding, I get no vibration or lack of braking so I don't know how long it's been that way. Is there anyway to try and fix this or rebuild the caliper or am I going to have to get a caliper. Thanks for the help.

 

[Mooseman]

You could try pushing it back in with a c-clamp. Put the brake pad on both pistons and put the c-clamp on the pad. If it's just a bit cocked, it should straighten out and go back in. Hopefully the piston or bore isn't scored or damaged and not leak.

Were the pads worn down a lot? Were the pistons really extended?

 

[Redbeard]

Check your brake fluid and bleed the brakes.

 

[Mazz]

I'll have to get things apart to really check this out, the inside set of pistons seem overly extended I guess I assumed that the outside set that seem stuck in was the problem, but it could be the overly extended pistons not returning. The pads are worn very evenly, everything seems fine until you look at it and the disk is way out of center. What are you guys using for brake fluid just any dot 4? I'll get it apart and report back, thanks again.

 

[Supa Dexta]

If its working fine and wearing fine, leave it alone and just ride it! You can worry about it next summer.

 

[dirk]

You could remove the caliper and use mild soap and water to clean the pistons, they should free up and if you push them in and out a few times while cleaning it'll remove most of the build up on the seals/pistons.

 

[Redbeard]

I'll have to get things apart to really check this out, the inside set of pistons seem overly extended I guess I assumed that the outside set that seem stuck in was the problem, but it could be the overly extended pistons not returning. The pads are worn very evenly, everything seems fine until you look at it and the disk is way out of center. What are you guys using for brake fluid just any dot 4? I'll get it apart and report back, thanks again.

Yes, DOT 4 fluid.
I had a similar problem a few years ago (my fault). I replaced my brake line and did not get one side bled off good enough. The sled still braked ok, but it braked better after I re-bled both sides again.
It's not impossible that moisture has collected in the system over time and corroded the piston bore causing it seize up??

My $.02

 

[Mazz]

Checked them out this morning, without taking anything apart. All four pistons still move so it might be a case of having to bleed them off good and see what happens. If that dosent work then off it comes to get washed up.

 

[Mazz]

Got the caliper off tonight and the problem seemed to be a pad hung up on the caliper. I got it all apart, filed down the edges of the pad, got it back together, bled the heck out of it and that seems to have fixed the problem. No miles on it yet but I'll keep an eye on it and report back. Thanks again for all the help.