Front brake caliper pistons won't retract

[Man_Named_Dave]

that's some crazy pressure you have there. out of curiosity, u didn't by any chance squeeze the brake lever when you put the 1st side back on? stupid question i know but it can happen

I think I must have inadvertently done this.
So I removed the first side's pads and I've been able to pry back one of the 4 pistons on the problem side. The others aren't budging though. I even took the caliper off the fork to make it easier but can't get any further. Suggestions?

[porndoguk]

G Cramp or Brake Caliper Rewind tool

[Man_Named_Dave]

G Cramp or Brake Caliper Rewind tool

What about just draining all the brake fluid? Wouldn't that release all the pressure so I could get the pads and pistons perfect, and then pour in brand new DOT 4?

[Malc]

Just draing the fluid won't help, and you'll need to rebleed them, which with a seized piston is going to be difficult.

There's got to be something seriously wrong if you can't push the pistons back in no matter what, and worse, if you don't fix it you're going to end up with glazed pads at best and warped discs at worst. Resorting to methods such as clamps and fuckin big levers ain't going to cure your problem.

I really suggest you consider stripping the calipers down completely. It sounds like you could have corroded pistons in which case a complete overhaul is required.

[porndoguk]

try twisting the piston instead of pushing it fella,

[Cammo]

I really suggest you consider stripping the calipers down completely. It sounds like you could have corroded pistons in which case a complete overhaul is required.

[veefer400]

I really suggest you consider stripping the calipers down completely. It sounds like you could have corroded pistons in which case a complete overhaul is required.

+2

Sort it, they arnt going to get any better and will certainly get a lot worse...

Its your brakes, ffs!

[amaechizzle]

Crack the bleeder nipple on the caliper... make sure you top up the brake fluid first.

Makes pushing pistons back heaps easier. And all the old fluid sitting in your calipers won't get pushed back into the system.

[Man_Named_Dave]

Thanks for the advice. I think I'll try to crack open the calipers and take a look on Sunday, try to get some pics of what I find!

Like you say it's worth making sure my brakes are perfect. It's just frustrating as I really wanna get the bike running so I can take it up to Yorkshire with me in 3 weeks!

[Sligeach]

if you are serious about the bike and any ways mechanically inclined, i would say just splint them.

it sounds as if the caliper seal has folded over on itself and is now stopping the piston from retracting.
the piston seals sit in a hollow grove and the least bit of corrosion in there and them become unseated.



http://www.mcnninjas.co.uk/forum/index. ... ic=75767.0

Thats a nice thread that give food for thought, i have rebuild my ZX6 and NC30 caliper now, its not a big deal.