Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: V6 CDX-er on 15 November 2010, 04:48:33

Title: Piston seized in front caliper
Post by: V6 CDX-er on 15 November 2010, 04:48:33
I'm in the middle of changing the discs and pads all round, and it seems like one of my front pistons is stuck fast, leaving me unable to fit new front pads on that side.

I've removed the cap for the brake fluid master cylinder and tried to squeeze the piston back in the caliper with some large water pump pliers, but to no avail. I then tried re-attatching the caliper housing to the bellhousing, and forcing the piston back with a large pry-bar, but obviously this doesn't work because of the dampers that adjust for brake wear don't allow me anything 'solid' to pry against. I don't really want to continue trying that route incase I damage or stretch these dampers.

Nor do i think it will be a good idea to spray the pistons with TT penitrating fluid as I would have thought that that may contaminate the braking system???

So, any ideas chaps, or do I just have the strength of a kitten? The side that I have done already was stiff, but not too bad. This side however seems to be stuck fast!  >:(

In advance, cheers.
Title: Re: Piston seized in front caliper
Post by: feeutfo on 15 November 2010, 05:24:21
may have to re attach it to pump the piston out, clean away any corossion, repair the seals and re fit. I am assuming a seal kit is available from vx? Or i believe they do an exchange service on calipers? details of it on trade club anyway, might be worth a call to the parts dept.
Title: Re: Piston seized in front caliper
Post by: alank46 on 15 November 2010, 07:28:14
Hi
If its that stiff you need to either repair the existing calliper or fit a new one.
Alan

Quote
I'm in the middle of changing the discs and pads all round, and it seems like one of my front pistons is stuck fast, leaving me unable to fit new front pads on that side.

I've removed the cap for the brake fluid master cylinder and tried to squeeze the piston back in the caliper with some large water pump pliers, but to no avail. I then tried re-attatching the caliper housing to the bellhousing, and forcing the piston back with a large pry-bar, but obviously this doesn't work because of the dampers that adjust for brake wear don't allow me anything 'solid' to pry against. I don't really want to continue trying that route incase I damage or stretch these dampers.

Nor do i think it will be a good idea to spray the pistons with TT penitrating fluid as I would have thought that that may contaminate the braking system???

So, any ideas chaps, or do I just have the strength of a kitten? The side that I have done already was stiff, but not too bad. This side however seems to be stuck fast!  >:(

In advance, cheers.
Title: Re: Piston seized in front caliper
Post by: Andy B on 15 November 2010, 08:14:10
Quote
I'm in the middle of changing the discs and pads all round, and it seems like one of my front pistons is stuck fast, leaving me unable to fit new front pads on that side.

I've removed the cap for the brake fluid master cylinder and tried to squeeze the piston back in the caliper with some large water pump pliers, but to no avail. I then tried re-attatching the caliper housing to the bellhousing, and forcing the piston back with a large pry-bar, but obviously this doesn't work because of the dampers that adjust for brake wear don't allow me anything 'solid' to pry against. I don't really want to continue trying that route incase I damage or stretch these dampers.

Nor do i think it will be a good idea to spray the pistons with TT penitrating fluid as I would have thought that that may contaminate the braking system???

So, any ideas chaps, or do I just have the strength of a kitten? The side that I have done already was stiff, but not too bad. This side however seems to be stuck fast!  >:(

In advance, cheers.

I've swapped the bleed nipple for a gease nipple & used a grease gun to move a piston.
I think the easiest option though is A N Other caliper. I'm sure there's enough cars being broken via this site for you to get one easily enough.  :y
Title: Re: Piston seized in front caliper
Post by: Omegatoy on 15 November 2010, 09:08:11
EEEK you should never attempt to force the pistons back without loosening the bleed nipple!!! you can reverse the seal in the master cylinder trying to do it wthout undoing the bleed nipple!
having said that WHEN THE bleed is open if no joy with water pump pliers or big grips, hold caliper in steady position agains disc, use a large enough socket that just fits  the piston and a small extension bar in the socket , through the cutout in the caliper,a sharp tap with hammer usuually gets them moving in then the grips can complete the job,
Title: Re: Piston seized in front caliper
Post by: Psychoca on 15 November 2010, 09:27:34
I use a G-Clamp with and old pad to gently push the piston back (bleed nipple open).
Title: Re: Piston seized in front caliper
Post by: Kevin Wood on 15 November 2010, 09:48:18
It's well worth investing in a proper wind-back tool, IMHO, because then you know you're applying even force to the piston. Certainly open the bleed nipple, though, as said.

This has the additional advantage that the fluid that has been sitting in the cylinder and getting hot will be discarded.

Kevin
Title: Re: Piston seized in front caliper
Post by: V6 CDX-er on 15 November 2010, 21:35:32
Quote
EEEK you should never attempt to force the pistons back without loosening the bleed nipple!!! you can reverse the seal in the master cylinder trying to do it wthout undoing the bleed nipple!
having said that WHEN THE bleed is open if no joy with water pump pliers or big grips, hold caliper in steady position agains disc, use a large enough socket that just fits  the piston and a small extension bar in the socket , through the cutout in the caliper,a sharp tap with hammer usuually gets them moving in then the grips can complete the job,

Thank you  :y

Slackening off the bleed nipple sorted it in no time. Kinda obvious when you think about it....... which I didn't  :-[


Thanks for all the advice and tips guys.
Title: Re: Piston seized in front caliper
Post by: Omegatoy on 15 November 2010, 21:42:00
Quote
Quote
EEEK you should never attempt to force the pistons back without loosening the bleed nipple!!! you can reverse the seal in the master cylinder trying to do it wthout undoing the bleed nipple!
having said that WHEN THE bleed is open if no joy with water pump pliers or big grips, hold caliper in steady position agains disc, use a large enough socket that just fits  the piston and a small extension bar in the socket , through the cutout in the caliper,a sharp tap with hammer usuually gets them moving in then the grips can complete the job,

Thank you  :y

Slackening off the bleed nipple sorted it in no time. Kinda obvious when you think about it....... which I didn't  :-[


Thanks for all the advice and tips guys.

most welcome!! glad you got it sorted, you will remember how to next time :y