I'm n the process of changing my pads on my HT, I have Shimano Deore Hydros.

On the rear (lack of brake last time out) I've taken the pads out and the outside piston is stuck fast, won't push back in at all subsequently I can't get the new pads in.

Any clues on how to resolve this quickly?

Usual approach is to attach track pump and blow it out.
ian

YOu need to get it moving – hold the other piton in and pump the lever until the piston starts to move out – clean and lube it then work it in and out a few times

Just use something solid to push it back in. Take time to make sure it is going in square.

It might help to position the lever in a horizontal plane, and open the reservoir cap before you do it.

Don't just push it in – if there is corrosion or baked on dirt on the piston you will wreck the seals. Get it moving out and clean it first.

If there is corrosion, you'll be needing a new piston. Shimano don't do spares IIRC, so you'll be needing a new caliper.

By all means clean it, but don't pop the piston.

Last time I had one that was really stuck I bodged an air cartridge onto the caliper. However there is a WARNING with this method, the piston will fly out at speed, I managed to embed one into the ceiling at work once!

Oh and get some disc brake cleaner in there before you move the pistons to remove any kak.

I usually just use a big screwdriver, works for me

Cheers folks,

Turns out the outter piston was stuck good and proper, a bit of free-up fluid and some lube and hey presto I've got rear brakes again.

Also gave them a damm good bleed – just as well the fluid came out a grubby colour with bits in it 😯

just as well the fluid came out a grubby colour with bits in it

I dont think thats healthy… perhaps have a look at the seals soonish? Shouldnt be getting bits from what I know.

Hmm,

They'll do for now atleast until I can afford to upgrade them anyway