Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: GastronomicKleptomaniac on 22 September 2015, 23:39:29

Title: Front caliper piston doesnt want to go back in...
Post by: GastronomicKleptomaniac on 22 September 2015, 23:39:29
After a senior moment, Ive had to try to put the pistons back into the front calipers.

Ive got one side in no drama, the other side just isn't playing ball. Ive Autosolled the piston to make sure there was no rust, applied the correct red rubber grease, and tried with an array of levers and even a caliper windback tool.

Regardless of master cylinder lid being on or off, bleed nipple open or closed, it just wont go more than a few mm in. My next port of call is a G clamp, then water pump oliers - unless anyone has any bright ideas? :D
Title: Re: Front caliper piston doesnt want to go back in...
Post by: 05omegav6 on 23 September 2015, 01:02:51
Needs to be perfectly square to go home :y
Title: Re: Front caliper piston doesnt want to go back in...
Post by: biggriffin on 23 September 2015, 05:09:51
Needs to be perfectly square to go home :y
Piston is round,  :-X  :o
Title: Re: Front caliper piston doesnt want to go back in...
Post by: GastronomicKleptomaniac on 23 September 2015, 05:47:41
Needs to be perfectly square to go home :y

Entirely possible its been off by a midgie's, especially given how shattered I was... Will have another look tonight. :y
Title: Re: Front caliper piston doesnt want to go back in...
Post by: Mr Gav on 23 September 2015, 11:22:03
Lubricate the piston seal with brake fluid and make sure the piston is square on and it should go in ok, some go in easy and some are a pita :y
Title: Re: Front caliper piston doesnt want to go back in...
Post by: 05omegav6 on 23 September 2015, 13:26:29
Needs to be perfectly square to go home :y
Piston is round,  :-X  :o
Now you listen here Andy P the second... :P
Title: Re: Front caliper piston doesnt want to go back in...
Post by: Andy B on 23 September 2015, 13:46:02
Needs to be perfectly square to go home :y
Piston is round,  :-X  :o
Now you listen here Andy P the second... :P

Don't you bloody start!!!  ::) I didn't say a thing
Title: Re: Front caliper piston doesnt want to go back in...
Post by: Diamond Black Geezer on 23 September 2015, 13:50:31
After a senior moment, Ive had to try to put the pistons back into the front calipers.

Ive got one side in no drama, the other side just isn't playing ball. Ive Autosolled the piston to make sure there was no rust, applied the correct red rubber grease, and tried with an array of levers and even a caliper windback tool.

Regardless of master cylinder lid being on or off, bleed nipple open or closed, it just wont go more than a few mm in. My next port of call is a G clamp, then water pump oliers - unless anyone has any bright ideas? :D

Managed to push both mine in by hand when mine were stripped down a couple of months back, with relative ease. I'd advise anyone to do this, a very worthwhile job. Given the piston is clearly already out, re-bleeding the brakes is a given, so I'm assuming you have the caliper 'on your lap/on the workbench', now?

Reason I ask is I'd probably struggle if it were still mounted on the car, maybe even find it impossible; but when it's sitting on your lap/on the floor it's easy, it will 'wobble' in, until it finds itself square, then push in by your thumbs. I found that brake fluid smeared on the piston and the rubber seal helped massively as a lubricant.   :)
Title: Re: Front caliper piston doesnt want to go back in...
Post by: GastronomicKleptomaniac on 23 September 2015, 14:26:19
Still attached to the car, I don't want to start undoing any more pipes unnecessarily ;)

I managed to get the other side straight in, so I shall persevere tonight.

Never know, my shocks might arrive tomorrow...
Title: Re: Front caliper piston doesnt want to go back in...
Post by: Diamond Black Geezer on 23 September 2015, 14:55:21
Well, fair enough, however, in for a penny, and all that. By which I mean you will need to bleed the brakes no matter what. Assuming you've got a clamp on the brake line, it doesn't matter whether the caliper is attached to the car or not at this stage. Mine were off for a week when I refurbed/repainted them any spare evening I had. There was a clamp on the rubber hose all that time, just an old dish beneath to catch any fluid that may have leaked out (none did).

Caliper back on, clamp off, bleed brakes. 24 hours later not even a mark/indentation/trace there'd been any clamp on the hose.

PS: Incidentally, the week timeframe was when the car was still SORN and all that was wire brushing and waiting for various coats of paint to dry, the actually 'piston in and out' took no time at all, a few mins if that.
Title: Re: Front caliper piston doesnt want to go back in...
Post by: GastronomicKleptomaniac on 23 September 2015, 15:54:14
I'm hearing you! I was surprised that the NS flexi- rigid joint came undone, I don't really want to push my luck, but if it comes to it I shall Plusgas the toffee out of it and give it a go.

The list of things to do didn't need "fanny about with calipers" adding to it... ;)
Title: Re: Front caliper piston doesnt want to go back in...
Post by: Diamond Black Geezer on 23 September 2015, 16:04:16
I'm hearing you! I was surprised that the NS flexi- rigid joint came undone, I don't really want to push my luck, but if it comes to it I shall Plusgas the toffee out of it and give it a go.

The list of things to do didn't need "fanny about with calipers" adding to it... ;)

Just checking we're talking about the same thing to undo... The banjo union that goes directly into the caliper, yes? with the flexi rubber hose? That's what needs to be undone to take the caliper off.

I forget the size, 10, 12mm thereabouts but they should come ondone fine. Strictly speaking you want a new crush washer fitting, mine got replaced with stainless steel once off the hee bay. (literally a few quid each) Of course, leave the caliper attached to the carrier to undo the banjo, catch the fluid that oozes out, then undo the caliper-carrier bolts, and get it on the bench, and slip the piston in.  :)

The union you need a proper flare spanner on, the one mounted on the inner wing - that is a 'I'm coming undone, or I'm rounding, and you won't know until the spanner slips, muahahaha' that's the one to worry about. But if you're taking the caliper off you don't need to even glance at that one. The one out the caliper will have been soaked in brake fluid its whole life and shouldn't be remotely difficult to remove, no worries.  :y
Title: Re: Front caliper piston doesnt want to go back in...
Post by: GastronomicKleptomaniac on 23 September 2015, 16:41:02
Funnily enough, its the one on the inner wing that came off without a fight! Hoes through the wing to the ABS unit, that pipe had corroded so as soon as I started fiddling underneath it, it cracked and leaked. Good thing I bought the full brake pipe making shindig!
Title: Re: Front caliper piston doesnt want to go back in...
Post by: GastronomicKleptomaniac on 23 September 2015, 16:42:10
FYI most of the suspension is in the process of being replaced, so theres currently no strut, spring or track rod on one side, and no strut on the NS. The pressure is on!
Title: Re: Front caliper piston doesnt want to go back in...
Post by: GastronomicKleptomaniac on 23 September 2015, 22:22:55
Success! Eventually levered it in, have had it in and out a few times now to make sure its free. (stop sniggering at the back).

Thank you chaps for the advice!  8)
Title: Re: Front caliper piston doesnt want to go back in...
Post by: Diamond Black Geezer on 24 September 2015, 10:20:44
Glad you're sorted. As a rule I tend not to go near brake unions, just make sure they've got a layer of grease smeared on them every once in a while, in my experience they either come or they don't, as said. If they don't then suddenly you've got a car that's off the road.  ;) Hope the rest is a bit more pain free  :)