One disc hotter than the other - stuck brake piston??

[Mully]

Howdy,

Came home tonight from work. Putting the disc lock on noticed the disc I was putting it on was quite hot. Thought it was a bit strange, so touched the other one, much cooler.

So, I'm thinking that one of the pistons may be stuck on, heating up the disc, Doesn't seem to pull one way or the other when braking.

How do I confirm/fix this?? Thinking I take the brake caliper off and work the brake lever while watching the pistons?? Would I be able to unstick the piston by working it back and forth??

TIA.

[Disco Dan]

have similar problem, one pad wheres quick the other.. hmmm...

Will be watching this thread.

Most likely a stuck piston I think.

[FROSTY:Me]

Caliper off,pads out,block off 2 pistons with a wood block. pump brakes.
Clean up piston that comes out with brakeclean or even just brake fluid.
Push piston back repeat process till alll 4 pistons are clean and moving smoothly.
or short version--bring it to me and I'll sort it

[Mully]

Caliper off,pads out,block off 2 pistons with a wood block. pump brakes.
Clean up piston that comes out with brakeclean or even just brake fluid.
Push piston back repeat process till alll 4 pistons are clean and moving smoothly.
or short version--bring it to me and I'll sort it

Jeez, you are officially a good knut (tm), Frosty.

[CB ARGH]

He's a bit of a nut too... rung him the other day... I'm like...

hi...

and ol' Frostie's like

WAZZZZZAHHHHP!

Good guy he is.

[riffer]

Caliper off,pads out,block off 2 pistons with a wood block. pump brakes.
Clean up piston that comes out with brakeclean or even just brake fluid.
Push piston back repeat process till alll 4 pistons are clean and moving smoothly.
or short version--bring it to me and I'll sort it

I'll second that. And add - don't try and use your fingers to hold back the pistons you don't want to come out.

It hurts.

[yod]

time for a clean up and new seals....

[Taz]

Maybe you're braking round more left hand corners than right hand corners?? Or vice versa?

[motorbyclist]

Doesn't seem to pull one way or the other when braking.

Maybe you're braking round more left hand corners than right hand corners?? Or vice versa?

i seriously doubt that having brakes working on only one side of a single wheel will somehow make that wheel turn or vice versa. sure it'd put a load bending the fork/swingarm, but that then causing the bike to turn? why would countless bikes only have single discs per axle, and often both on the same side of the bike?

open to a logical explanation though, cbf doing the maths myself right now

[Taz]

I was just taking the piss.

[Katman]

Rather pointless just cleaning up the pistons because that's not likely to be where the problem lies. Once the pistons are out the seals need to be removed from the calipers and the layer of shit that builds up on the back side of the seal and the grooves the seals locate in needs to be scraped clean. The problem is caused by the layer of shit forcing the seals into a tighter contact with the piston and therefore not allowing the piston to retract properly.

[FROSTY:Me]

Rather pointless just cleaning up the pistons because that's not likely to be where the problem lies. Once the pistons are out the seals need to be removed from the calipers and the layer of shit that builds up on the back side of the seal and the grooves the seals locate in needs to be scraped clean. The problem is caused by the layer of shit forcing the seals into a tighter contact with the piston and therefore not allowing the piston to retract properly.

Sorry dude --specific question about specific bike by an owner with limited mechanical experience.
Im not happy recomending deeper exploration in this case.

[Mully]

Sorry dude --specific question about specific bike by an owner with limited mechanical experience..

Cheers Frosty. Seems to have solved the problem in the meantime anyway.

Thanks for the advice too, Katman. Looking at something similar in the near future (once I can afford to bribe Frosty suitably to *ahem* assist).

Was thinking new pads, new fluid and a general clean up of pistons, etc.