Can't retract brake piston

[firewallguy]

Trying to fit new brake disks but can't get on of calliper piston to retract so i can fit pads. One side went in fine with g-clamp but other side won't budge.
Recently had callipers refurbed so won't be happy if it's no good.

[firewallguy]

Mmm, finally got it to go but makes me wonder if that piston will stick in future, had the refurb done due to boiling fluid on track day.

[Tanguero]

Personally I would send that straight back to the rebuilders to be checked over, both from the point of view that it should never have stuck in the first place and to be sure that the efforts to retract it havn't done any damage.

Don't take a chance with life critical components!

[jamieduff1981]

If it won't retract easily then it won't stroke out easily either.

[ukkid35]

firewallguy said:

Recently had callipers refurbed so won't be happy if it's no good.

What was the pad wear like after the refurb?

[firewallguy]

I haven't used them yet to be honest. I put them back on with my old disks, drove it back into the garage then decided to get new disks to go with them. I think i let the one piston come out too far when retracting the other side.
Gonna see how i get on, can't face taking off the road again just yet, needs it's mot in next 2 weeks.

[Tanguero]

firewallguy said:

Gonna see how i get on, can't face taking off the road again just yet, needs it's mot in next 2 weeks.

You sure you want to take a chance with a brake failure?

[TimJM]

You used a g clamp to move a piston?

Perhaps i have a problem with mine then. I used my thumb to push them back in. I've never worked on brakes before and thought calipers should move freely but i have just seen you can buy tools to move calipers and now your comment has got me worried.

[ukkid35]

Tanguero said:

You sure you want to take a chance with a brake failure?

In all fairness, that's not going to result in brake failure, rather more likely a violent pull, which could be even worse!

[Vee8ight]

firewallguy said:

I haven't used them yet to be honest. I put them back on with my old disks, drove it back into the garage then decided to get new disks to go with them. I think i let the one piston come out too far when retracting the other side.
Gonna see how i get on, can't face taking off the road again just yet, needs it's mot in next 2 weeks.

You could have popped a seal out, don't risk it, if you can't check them then take it to someone who can, or taking it off the road might be the last of your worries, when you've had an accident!

[Supateg]

In AP's blurb somewhere, if you pop a piston out, dip it in brake fluid and re- insert. I doubt this has happened as you didn't mention brake fluid all over the place when the piston came out too far. This shouldn't be a problem.
I noticed when I refurbish mine once installed with new seals it was important to push the piston home then out and back again to make sure the seal was centered and lubed. The difference between this and just inserting the piston was a free sliding piston and one that required quite a bit of clamping to retract it.
How long ago we're they refurbed?

[Tanguero]

ukkid35 said:

Tanguero said:

You sure you want to take a chance with a brake failure?

In all fairness, that's not going to result in brake failure, rather more likely a violent pull, which could be even worse!

Unless of course the seal is knackered after forcing the piston back in, and it suddenly bypasses fluid. Of course you would still have the brakes at the other end of the car