brakes

[6274rico]

hi ,has anybody had any probs with front brake on traveller.did a 175 mile run sunday no probs. today set off did 60 mile then front locked up solid. left it to cool.set off home had to stop 5 times with same prob. pulled pads out released calliper and squeezed lever all piston were free.could even push em all back with fingers. any ideas. cheers all. steve.

[Anna]

Can't say I've seen that one before, Steve. Have you checked the disc is OK?

I've got a sticky piston at the minute which makes braking a well-planned exercise! It also surges a bit which makes me think the disc is a bit out of whack. Will have to sort it sometime. Any advice for un-sticking pistons without dismantling the whole system? I tried the g-clamp trick a few weeks ago and it doesn't seem do have had much lasting effect.

[BlueRidgePanther]

What's this G-clamp trick? Never heard of it myself.

I'd say, for both of you, the first step is to make sure everything is straight. If you've disassembled your caliper or wheel recently, you may have reattached it slightly crooked. I'd start by untightening, straightening the assembly, and then retightening every bolt carefully.

[Anna]

I knew someone would ask that. The g-clamp trick goes like this:
1) take caliper off disc
2) take pads out
3) get a (small) g-clamp or similar and clamp all except one of the pistons in place (as far back as they'll go) - Gently! Don't damage the piston faces or sides
4) pump the lever to push the remaining piston out, forcing it to move if it's stuck, as none of the other ones can and hydraulics works like that. BE VERY CAREFUL not to pop the piston out completely else you'll be bleeding the system for the next week... Said piston can now be cleaned up if it's got a bit of corrosion around the line where it usually sit or whatever. Again, carefully!
5) push the piston back and repeat 4) if desired. Coppa-slip or similar the piston before pushing it back for the final time.
6) rearrange the g-clamp(s) so a different piston can move & repeat 4) and 5)...
7) repeat 4), 5) & 6) as many times as necessary to do all the pistons.

I TAKE NO RESPONSIBILITY FOR ANY PROBLEMS CAUSED IF YOU TRY THIS - IT'S JUST WHAT I'VE BEEN TAUGHT BY CANNY OLD MECHANICS WHO SHOULD PROBABLY KNOW BETTER.

This obviously works best on systems with a limited number of pistons, but if you've got enough small g-clamps I don't see why it wouldn't work on a 6-pot Nissin. And sometimes you need VERY small g-clamps, but it works very well on freeing up stuck pistons. And you can just about use a standard size g-clamp on the Skorpion piston if you're careful and don't knock it off.

I'll have a look at the straightness issue, it's one of those things that I think it's "always" done, but we haven't "always" had the bike and it's definitely getting worse. Thanks BRP.

[DAVID THOMPSON]

english is wonderful england its G clamp usa its C clamp

[Anna]

of course, silly me.

[handsomejackuk]

big screwdriver and a piece of wood always works for me.....

Al.