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31

Omega General Help / Re: Brake imbalance

« on: 10 July 2018, 18:49:05 »

The ATP set for £69 is about the best value available 

Currently on ebay.

Had a look just in case I need them but couldn't find on eBay.

32

Omega General Help / Re: Brake imbalance

« on: 09 July 2018, 10:32:30 »

I wouldn't fit Delphi wishbones to a scrapped Omega for banger racing

Last one I fitted lasted less than a week. Start there

I had the same experience with my beloved TD Estate years ago. Fitted Delphi, they lasted less than a year.

Thanks for the reply.  The only reason I fitted them was that I've had a set of Delphi's on our workhorse Astra and they've been great for many years so I thought they'd be ok on the Omega too. Previous (unknown brand) set fitted to the Omega by a local garage lasted barely 18 months with very low mileage so I was hoping to improve on that.  Is there a brand that is recommended other that GM?

33

Omega General Help / Re: Brake bleed screws

« on: 08 July 2018, 23:07:05 »

Surely they're just a standard M10 long bleed nipple, available anywhere?


Like THIS?


That price seems a bit expensive to me, but it was the first one in the search

On the MFL Omega I had they were all standard M8, but others have suggested that they had a mixture of M8 & M8 fine. 

So M10 or M8? (didn't know there was an M8 fine option to contend with too, thought they'd just be one standard thread). I've tried looking up the part number 90369391 given by johnnydog but none of the few references I can find say what thread it is. I guess I can measure the screw against an M8 or M10 bolt to work it out but thought it would be straightforward and was going to order a couple tonight.

34

Omega General Help / Brake bleed screws

« on: 08 July 2018, 19:08:00 »

Could someone tell me what the correct bleed screws are for the front Lucas calipers please - i.e., correct thread, length, pitch (if relevant), part number and where to get some if possible. Biggred seem to have loads but I'm not sure which ones are right.

The same info for the rears would also be appreciated.

35

Omega General Help / Re: Brake imbalance

« on: 08 July 2018, 19:02:51 »

I wouldn't fit Delphi wishbones to a scrapped Omega for banger racing

Last one I fitted lasted less than a week. Start there

No idea they were that bad, will check them again.

36

Omega General Help / Re: Brake imbalance

« on: 08 July 2018, 19:01:28 »

had a caliper with a problematic piston before , very odd
kept sticking , worked it in and out and all was fine for a week or so , then the same again
I'd inspected it ,no rust etc
I replaced it with a known good used item
examined the dud unit with digital micrometer
the piston had gone "out of round"
which if you think about it ,can happen because the piston does get dragged in one direction by it's pad and calipers all the time during braking, not much but enough to cause the issue

If it was my car (or one i look after) I would buy a used replacement caliper(would be cheap and easy to get hold of) i
present for mot early , if there is an in-balance issue  then you have the spare ready to go on
but you can't rule out other issues like a dud ,semi jammed/part blocked  solenoid in the ABS module etc
IF all the slides / pads/ discs  / fluid /wheel bearing  etc is ok (including manufacturing faults so compare o/s and n/s for any slight size differences etc)
and you've checked the suspension components both sides
(it could be a duff component on on the non pulling side that makes the car pull to the problem side )

also, familiarize yourself with the RBT procedure as per the video and watch them do the test if possible 

not that i'm saying your garage is one of the bad ones , it does sound like you have an issue

I just don't trust garages

I'm fortunate to have an MOT tester that is strict but fair

I've missed things in the past ,he has too , we are all human
 (though Mrs Builder may argue that point about me  )

That is interesting. If the piston has gone slightly 'out of round' like you say it could explain why the fault seemed to appear when I changed the pads and the piston - i.e., the piston may have round in the old position for the worn pads. Also I'm going to do as you suggest and try and find another caliper to play around with - if I'm lucky I might be able to find one that has been in use recently and is still ok. I'm also going to have another look at my wishbones.

37

Omega General Help / Re: Brake imbalance

« on: 08 July 2018, 18:51:55 »

When I recently took mine for test the front brakes were 12% out of balance.(within limits ) but I wasn’t happy with that. I rechecked all the pads ,replaced the front discs and re bled the system.took it back and they were still the same.rellaced front hoses ,re bled and tried again. Still the same.garage said they were fine and nothing I could do would make them 100% perfect. No cars are apparently.no signs of any pull either.
I still wanted them better so I rebuilt both calipers noticing that the lower side DID have some slight rusting on the piston ( the others were finger push,this was tighter but not in any way seized)and a SLIGHT wetness on piston.
Rebuilt,all finger push to retract now,rebled and back again.
Brakes now less than 1% out of balance.(0.7%) 229/230
So mine was definately a caliper issue. To be honest I don’t think it was the slightly stiff piston,more like the slight leak drawing a very small amount of air in on release.

I'm going to have a look at both callipers again, this week I hope. Although both are going in and out ok I may be able to feel if one is a bit freer than the other when I push the piston back in.

38

Omega General Help / Re: Brake imbalance

« on: 08 July 2018, 18:43:17 »

Thanks Dave. I enjoyed those testers' guides enormously, and learned a lot from them.
The OP had a steering pull last year's MOT, tester failed the car. After some fiddling OP improved matters slightly and car just passed on retest. Car still has a steering pull and is soon due for test again. Car is 22 years old, and must have had wishbones changed. Do you know when they were last changed, Greenbay Packer? Was a new pair fitted, or just one? What make were they? As I said in post 9 of this thread, it was very obvious to me mine were faulty, watching from below as car above me braked. Without a pit its hard to imagine a simple test. Perhaps you could lever both front bushes in turn with front of the car on axle stands.

Thanks for the replies and sorry for the slow response - just back from holiday. I'm going to check the wishbones again as much as anything to make sure I don't have two faults at the same time - its always possible I've sorted the caliper issue, hence the improvement which got the car through the last MOT, but also have a wishbone bush starting to fail which is responsible for the slight twitch and straighten I can feel now. Not entirely sure how old the wishbones are off hand but both sides have been changed more than once. Current wishbones are Delphi, which certainly looked ok.

39

Omega General Help / Re: Fuel filters

« on: 07 July 2018, 23:06:42 »

You'll never notice a difference between them, buy on the usual cost/convenience basis.
The clips are on the fuel lines, so be careful how you disconnect them

Great, thanks.

40

Omega General Help / Fuel filters

« on: 07 July 2018, 13:20:36 »

Does anyone have any thoughts on petrol fuel filters - i.e., Mann, Crosland, Comline, Meyle, Bosch, etc. Is there much difference between them in quality and do they all come with new clips?  Thanks.

41

Omega General Help / Re: Brake imbalance

« on: 01 July 2018, 11:36:32 »

If you're going to pump the piston out a bit further you'll need to put the old pads in first anyway.Whatever you do don't try pumping the piston out with nothing in the way to stop it coming out altogether.

 

42

Omega General Help / Re: Brake imbalance

« on: 26 June 2018, 08:35:58 »

Yes ,dead easy,especially as it’s only a single piston type.to be honest though if the inside of the boot is dry and the piston not rusty and you can push it back nice and easy you won’t achieve much by rebuilding it the usual cause of imbalance on these is the two slider pins/bolts but you have already checked them. The way to get balanced readings(within tolerances) is to have equal physical properties each side.this means identical pad composition,disc condition,caliper condition,hose condition and all new fluid.you will never get a balance of absolute zero but one side coming on before the other USUALLY means that the faulty side has an issue somewhere.nothing to do with anything on the suspension ,bushes,tyres ,etc as the brake rollers are only measuring the effect of what it sees the brakes doing.
Have you got a good pedal!. If not you could still have an air bubble somewhere on that side in either the pipes,abs unit or caliper .

Thanks for the reply, its confirmed what I was thinking particularly with being able to rule out things like suspension, tyres, etc, which is a big help. The pedal is good and firm and its position doesn't change when I pump it. I was hoping there may still have been some air somewhere and that the rebleed I've just done would help but it doesn't seem to have made any difference. I might try pumping the piston out a bit further as I've only seen about 1/2" of it so it may be in worse condition further inside the caliper. The problem only seemed to arise after I'd changed the discs and pads and the caliper piston was pushed right in to take the new pads. I've actually been contemplating putting the worn pads back in briefly just to see if there is any difference with the piston operating further out of the caliper bore but I know that's a poor idea as the old pads will be worn differently.

43

Omega General Help / Re: Brake imbalance

« on: 25 June 2018, 23:00:49 »

Just make 100% sure that the piston retracts into the caliper as easily as the other caliper.and also peel back the piston dust cover if you can to make sure it’s dry inside, a small leak here can cause a small amount of air to be drawn back into the caliper as well.it could be hoses as you have previously thought but it’s rare and the tester would have felt them under pressure anyway.
[/quote]

Thanks, its definitely bone dry inside the boot but I think I'll do as you suggest and have a look at the other caliper too just to see if one side is moving more freely than the other. I'm guessing/ hoping the callipers are fairly easy to rebuild if the correct seal kit and/ or new piston is available.

44

Omega General Help / Re: Brake imbalance

« on: 25 June 2018, 10:38:11 »

Yep, if the MOT brake tester shows an imbalance then it's clearly not down to the bushes. That doesn't mean they are OK, of course.

I can't remember how the brake circuits are split on an Omega. A problem anywhere other than the caliper would affect both sides equally if they're on the same circuit, which I think they are.

Thanks for that.  Its beginning to seem like I might as well start by looking at the caliper and either replace or overhaul it.

45

Omega General Help / Re: Brake imbalance

« on: 25 June 2018, 08:52:18 »

It could be the wishbone front bushes. I had a car, just passed its MOT, but before I handed it over to my son I wanted to correct a brake pull to the left. I had the wife drive it slowly over the inspection pit, with me in it, and brake. It then became obvious to me that the wishbone front bushes were unmatched, causing a steering twitch. I changed the wishbones, and the fault disappeared.

I'll have another look at the wishbones but was assuming this kind imbalance wouldn't show like it did on the MOT brake test, i.e., indicating that one brake was operating ahead of the other?