Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: RacingSnake on 14 January 2014, 20:59:23
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Has anyone had a problem with vague steering and feeling of wandering with their Omega?
Initially I thought it was the front end that was the cause, so I've changed front dampers, springs, wishbones, anti-roll bar links and the steering idler. This has helped tighten things up no end. However the car still wanders and I'm now convinced the problem is rear wheel steer. I've read up about the rear axle mounting bushes (donuts) and got a couple on order which I should hopefully get fitted on Thursday. But if these aren't the culprit, does anyone have any other ideas what could be the cause please?
Appreciate any thoughts :y
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Alignment mate :y
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Sorry, should have mentioned I had a full alignment done after fitting the new front suspension components. I can have a free re-check and asjust in a month so ideally would love to get everything sorted by then.
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Appreciate any thoughts :y
a steering box (as fitted to an Omega) is more vague than a steering rack
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Did you get a print out from the alignment shop? Would be good to see what they've set yours at so we can compare to WIM settings mate :y
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Has anyone had a problem with vague steering and feeling of wandering with their Omega?
Initially I thought it was the front end that was the cause, so I've changed front dampers, springs, wishbones, anti-roll bar links and the steering idler. This has helped tighten things up no end. However the car still wanders and I'm now convinced the problem is rear wheel steer. I've read up about the rear axle mounting bushes (donuts) and got a couple on order which I should hopefully get fitted on Thursday. But if these aren't the culprit, does anyone have any other ideas what could be the cause please?
Appreciate any thoughts :y
Almost certainly donuts, usually signified by the rearward steer giving zero sensation of a pull through the steering wheel.
Only remaining factors once replaced, are;
Dif blocks to chassis separated, usually only after galactic miles or jacking on the dif.
Set up. Lube your rear track rod adjusters while your under there.
Tyre wear.
...IME.
As always, fault find. Repair (everything chassis related). Set up. New tyres.
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Tyres?
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Tyres?
Although, as Ian suggests, Ffff, Ffff, fer fer FALKEN tyres can bugger a cars handling all on their own.
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I only speak through experience. Old omega had the same problem after replacing every conceivable steering and suspension component with no luck I changed the tyres and hey presto no more issues :y
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I only speak through experience. Old omega had the same problem after replacing every conceivable steering and suspension component with no luck I changed the tyres and hey presto no more issues :y
Badly/oddly worn?
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I actually had four new tyres yesterday as the guys at the wheel alignment place said I only had 3mm tread left on the fronts and 2mm on the rears. Thought I'd better bite the bullet and get them replaced with the lovely weather we're having! In the past (on other vehicles) I've found Kumho's to be decent medium range tyres so I've gone for them. They're not directional so if I do have trouble with camber wear I can always have them turned round to get more mileage out of them.
The following wheel alignment values were achieved:
Front toe LH = +0.4mm
Front toe RH = +0.6mm
Total toe = +1mm
Front camber LH = -00°50'
Front camber RH = -01°00'
Front caster LH = +05°00'
Front caster RH = -02°10'
Rear toe LH = +0.6mm
Rear toe RH = +0.3mm
Total toe = +0.9mm
Rear camber LH = -02°00'
Rear camber RH = -02°10'
The only thing that gives me concern is the front RH caster seems to be far out, and the numbers were the same before and after adjustment so presumably no attempt was made to change it. Can you even change the caster?
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I only speak through experience. Old omega had the same problem after replacing every conceivable steering and suspension component with no luck I changed the tyres and hey presto no more issues :y
Badly/oddly worn?
Ever so slightly on inner edge but that might have been due to old set up, changed them as it was last possible thing I could think of
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I actually had four new tyres yesterday as the guys at the wheel alignment place said I only had 3mm tread left on the fronts and 2mm on the rears. Thought I'd better bite the bullet and get them replaced with the lovely weather we're having! In the past (on other vehicles) I've found Kumho's to be decent medium range tyres so I've gone for them. They're not directional so if I do have trouble with camber wear I can always have them turned round to get more mileage out of them.
The following wheel alignment values were achieved:
Front toe LH = +0.4mm
Front toe RH = +0.6mm
Total toe = +1mm
Front camber LH = -00°50'
Front camber RH = -01°00'
Front caster LH = +05°00'
Front caster RH = -02°10'
Rear toe LH = +0.6mm
Rear toe RH = +0.3mm
Total toe = +0.9mm
Rear camber LH = -02°00'
Rear camber RH = -02°10'
The only thing that gives me concern is the front RH caster seems to be far out, and the numbers were the same before and after adjustment so presumably no attempt was made to change it. Can you even change the caster?
I would say it was out by them figures (I might be wrong), can't remember the setting when I had mine done.
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That front castor is oppsed. Needs the front subframe moving. Which means starting over.
Camber should be nearer -1.10 than that too really. But seen worse on that front.
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That front left hand camber is way out when comparing to WIM spec.
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That front left hand camber is way out when comparing to WIM spec.
I hope not as was set by a garage listed on the WIM website!
Bear in mind that the springs and dampers are brand new, so I would hope they would set it to the lower tolerance so that in time when the springs sag the camber does not increase beyond a level to cause damage to the tyres.
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That front castor is oppsed. Needs the front subframe moving. Which means starting over.
Camber should be nearer -1.10 than that too really. But seen worse on that front.
Moving the subframe sounds a mare of a job. Is a WIM garage even going to be able to do this?
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That front left hand camber is way out when comparing to WIM spec.
I hope not as was set by a garage listed on the WIM website!
Bear in mind that the springs and dampers are brand new, so I would hope they would set it to the lower tolerance so that in time when the springs sag the camber does not increase beyond a level to cause damage to the tyres.
Just checked Autodata at the standard Vauxhall spec (ignore the WIM settings for now) and your camber reading's even worse! it says here it should be 1 degree 40'' +/- 45.
Yours is way out. What shop did you use?
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That front castor is oppsed. Needs the front subframe moving. Which means starting over.
Camber should be nearer -1.10 than that too really. But seen worse on that front.
Moving the subframe sounds a mare of a job. Is a WIM garage even going to be able to do this?
It's not too bad. Loosen the 6 sub frame bolts, lever the subframe within the play of the bolt holes to settings, tighten bolts. But as everything hangs off the subframe, it will alter the camber and toe, so the entire front end will have to be re done.
Wim are aware of this. Can't speak for the franchises though. :-\
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Yours is way out. What shop did you use?
I'll PM you
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That front castor is oppsed. Needs the front subframe moving. Which means starting over.
Camber should be nearer -1.10 than that too really. But seen worse on that front.
Moving the subframe sounds a mare of a job. Is a WIM garage even going to be able to do this?
It's not too bad. Loosen the 6 sub frame bolts, lever the subframe within the play of the bolt holes to settings, tighten bolts. But as everything hangs off the subframe, it will alter the camber and toe, so the entire front end will have to be re done.
Wim are aware of this. Can't speak for the franchises though. :-\
Thanks for the advice. Looks like a trip to WIM HQ looks the way to go then.
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Just checked Autodata at the standard Vauxhall spec (ignore the WIM settings for now) and your camber reading's even worse! it says here it should be 1 degree 40'' +/- 45.
Yours is way out. What shop did you use?
As said, 1o10" is a better target to aim for. Recommended figures are no use once the suspension has got a bit of wear on it.
As for +/-45' tolerance... If the job's worth doing.. ::)
Agreed, that caster value is way out, though. It won't drive straight until that's resolved. I'd venture to suggest that something is bent for it to be that far out, but might just be subframe alignment.
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Just checked Autodata at the standard Vauxhall spec (ignore the WIM settings for now) and your camber reading's even worse! it says here it should be 1 degree 40'' +/- 45.
Yours is way out. What shop did you use?
As said, 1o10" is a better target to aim for. Recommended figures are no use once the suspension has got a bit of wear on it.
As for +/-45' tolerance... If the job's worth doing.. ::)
Agreed, that caster value is way out, though. It won't drive straight until that's resolved. I'd venture to suggest that something is bent for it to be that far out, but might just be subframe alignment.
If -1°10' is the recommended target, I'm not that far out then.
However it seems to be a bit academic at the moment though if the caster needs resetting. The car has never had an accident in the time my family has had it, and we've had it since it was 1 year old. Any ideas what could be bent? It's recently had new lower wishbones so it's not them. Unless the whole subframe is bent out of alignment, but it would need to have been a hefty whack to do that though I would have thought.
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There's huge gob in the subframe holes. Huge.
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I'm guessing you'll be running 17 inch wheels then ?
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Hang on a sec boys.
My R/H front camber was (and still is) 1o 35''. This ''technically'' is in spec. When I posted these results up WIM and a few members said that even though the tolerance is +/- 45'' this was way out and needed adjusting or I'm going to get severe wear on the shoulder.
Yet we're looking at these figures of Racing Snake's and no one's concerned about the camber figure being 0o 50''.
Only difference between RS's figures and mine is 5''. So surely he should be having the same concern over the tyre wear on the shoulder as well? Or have I missed something ;D
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Rs's camber is the more vertical side of -1.10.
Where as yours was cambered more than -1.10.
I haven't checked what been quoted to what scale but also consider some places work in 100ths (?) of a degree. Wim work to degrees and minutes (60 minutes to a degree, not a 100th) or something like that.
But as said, it's matters little, as the caster error means it will all go to cock when the subframe is moved.
Yours, as we know on here, will give shoulder wear at the book settings of -1.45 mins.(15 minutes away from 2degrees)
Ime there is no case at all for setting camber beyond 1.15 even on sports suspension, and the likes of irmscher providing top mount stickers Warning owners that camber MUST be set to -1.40. Mins. Utter bollards.
1.20 will cause excess wear by the time the middle tread is low. Set it to -1.40 and you'll have tyre strands wacking the shock mount spring cup in under 7k miles.
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That explains it Chris. thanks for that! :y
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Right then, just a quick update to this thread. Thank you very much to all who replied and gave advice.
I had the two rear axle mounting bushes replaced today, and the handling has improved dramatically, so it appears these were a culprit. Absolute bugger to get out though apparently!
In a few weeks (once the new suspension has settled a bit) I'll go and get another wheel alignment done and hopefully that will be the handling problem sorted.
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A quick question for you knowledgeable people:
Would the process of changing the front dampers affect the caster angle?
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A quick question for you knowledgeable people:
Would the process of changing the front dampers affect the caster angle?
No. Not beyond manufacturing tolerances, which will be minuscule as far as caster angle goes.
Only way is too move the subframe.
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A quick question for you knowledgeable people:
Would the process of changing the front dampers affect the caster angle?
No. Not beyond manufacturing tolerances, which will be minuscule as far as caster angle goes.
Only way is too move the subframe.
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Thanks for your reply Chris. That's interesting. I've just found the printout of a wheel alignment check I had done (at my local tyre place, not the one I used that listed on the WIM website) before I changed the front suspension and anti-roll bars. It gave the front caster as approx 5° both sides.
Seems very strange then that one side changed by 7° after fitting new suspension. I'm now wondering whether the guy set the equipment up incorrectly, and that in fact my caster is actually perfectly all right.
I need to go back in a couple of weeks for a free re-check anyway so I'll see what it comes in at then.
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The key is the position of the wishbone ball joint to hub, this effectively moves the wheel for and aft as well. Moving this forward or back, via the subframe, sets the caster.
This assumes that the bushes are structurally sound, and capable of holding the desired position. Or as a Kev said, something isn't bent.
That is a prety huge error. Does the wheel look central in the wheel arch for and aft? Or another way, as the bumper could be loose, is it the same distance from rearward side of the wheel arch to the tyre on both sides...? A simple 3 finger test should show an error that big.
If bushes are sound and the gap from tyre to wheel arch is the same both sides, you might be right and they just cocked it up.
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Just to give an outcome to this wheel geometry problem, I went back to the tyre place after a month of fitting my suspension components to let them settle. A different guy performed the wheel geometry check this time, and immediately the numbers looked more sensible. Both front caster was approx 5° both sides before any adjustments. The tracking needed a tweak, but nothing else needed changing.
Therefore it does seem that the 7deg difference side to side was down to operator error. I wish I had been a bit more on the ball when the alignment was set first time. But I needed to go back again once the suspension had settled, and hindsight is a wonderful thing.
If anyone else has spurious results on a wheel alignment check, I'd definitely recommend getting a second opinion, or getting the garage to double check.