Re: Stuck brake piston
 

Have you tried these Luke?

http://cdn5.mydeco.com/product_image...a5e223e77b.jpg

What bike is it on?

Re: Stuck brake piston
 

Some dangers of the err interesting advice so far.
If you muller the piston with mole grips, which is inevitable, you can also distort the piston out of round which clamps it in good and proper.
If you apply penetrating oil you may swell the seals and clamp it in tighter.

If you are going to attack it with mechanical tools, wind a jubilee clip around the offending piston.

Hydraulic method is best and safest way (preferably BEFORE you split system!). If you can seal the passageways in the caliper, you can replace one piston, fill it with water and then use a G clamp to force that one in, so popping the other out.

If you are going to use some caliper removal tool the expanding mandrel type ones are brilliant, the actual plier type ones are ok but haven't really got the balls behind them to pull a proper stuck one.

Re: Stuck brake piston
 

put the other pistons back in,you may have to hold these in with a clamp or a vice and pump the stuck piston out with a grease gun,a air line will put out a 150psi, a grease gun about 10.000 psi and you cant compress grease so it has to move

Re: Stuck brake piston
 

Cheers for all the replies, I have a few things to try :)

Re: Stuck brake piston
 

worked on the race callipers that i was working on, although they had no dust seals so that could affect the way it worked

Re: Stuck brake piston
 

Not saying it will never work, just pointing out the risk of it.

Re: Stuck brake piston
 

ohh right fair enough, the only thing we were told not to use is stuf like brake cleaner around the seals as they will blow them (yes you cant use brake cleaner on "brakes".... :???: can use it on every thing else though :p )