Rich-T

Just been stripping my 4 pot calipers to install new pads and have come unstuck. One of the pistons in the caliper will not re-seat, flush in the caliper. They were a little sticky and I don't think this piston had been moving much as there is corrosion on the inside of the disk face. Now it has moved but refuses to go back! I've tried G-clamp, hitting it etc but with no success. Also drained the fluid from the caliper incase that was causing it. How can I get myself out of this pickle?

TonyBurns

iTrader: (3)

Is it stuck due to corrosion on the inside of the piston housing?
If so try some emery cloth to clean it all off
Or you can buy one of the paint kits that comes with some acid stuff that eats through the rust

Tony

Aztec Performance Ltd

iTrader: (234)

Don't take chances with brakes.

Did you inspect the piston for pitting/corrosion and replace the seals?

Rich-T

Initially it must have been stuck due to corrosion somewhere, however it has now moved outwards but will not return. There is a little play left to right but no travel rearwards. The pistons appear clean and corrosion free when I looked at it. The rubber seals are in fine condition with no splits or gaps. Could I have over extended the piston and unseated the it from the caliper some how?

Aztec Performance Ltd

iTrader: (234)

What did you do to remedy the sticking piston?

Rich-T

I applied pedal brake pressure with the brake pads removed which unstuck the sticky piston and allowed it to travel outwards into the space where the pad would have sat. Have I done something very wrong?

Aztec Performance Ltd

iTrader: (234)

Not as such, but if it was sticking in the first place I wouldn't just expect to pop it back in and for all to be ok.

I would inspect all pistons carefully and replace those that need replacing. Inspect bores and replace all seals (they are only about £25).