Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: terry paget on 28 June 2014, 09:36:58
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OE03 EWW 3.2 police special manual saloon
I know this forum, and the maintenenace guide, recommends changing wishbones in pairs, but I cannot see why, any more than changing trackrods or drop links in pairs. It sounds like common sense and good practice, but it means changing a perfectly good wishbone just because its chum has one dodgy joint.
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You can do what you want.
Drop links are usually just as worn on both sides or not far behind. I suppose the reasoning is that upon closer inspection, the other side will be not far behind in wear.
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Also factor in that a wishbone change will require a suspension setup afterwards - could be the best part of £100. Not much point in doing half the job, as the other side won't be far behind.
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Numerous reasons.
Firstly uneven performance is to be avoided.
Especially if you have oe bushes, this doesn't apply to poly. If one oe front bush fails and is replaced tother will be softer, so given the level of toe out on the brakes designed into the bush movement you could get the car bearing off under braking or emergency braking.
Rearward bush also but less likely as there is less give in that one.
Then there's the set up issues as Kev says.
Changing bones means set up after. Changing one means set up. Then set up again when the other fails soon after. Plus you've got all the tools out, you may as well do both.
But the main reason is to give even performance across a given axle. It's the soft squidgy bits that need to be even. Bush play on bones. Spring rates and damping rates.
Oil and gas in the shocks. Etc.
Drop links don't really apply to the same level as the play just causes an annoying knock. It doesn't affect performance to have 0.05mm of play in one drop link. Only thing to consider is tother side won't be far behind on wear. There no set up either obviously.
There's owners preference to consider. Most people don't want the agro so may as well do drop links while doing bones, is one line of thinking. I wouldn't change them unless they knock personally.
But in short. Reason is, even performance across a given axle. :)
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Thank you gentlemen, for your wisdom and experience.
No-one has mentioned track rods, the one item of the three listed that is adjustable.
I struggle to see why changing a wishbone for another dimensionally identical item should affect the steering geometry; it should put it back to where it was before the old wishbone went soft. It should not change castor angle, camber angle, or toe-in.
Track rods, on the other hand, however carefully fitted, always need adjustment to make the steering feel right and avoid squeal on cornering.
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The wishbones are within tolerance, not identical... the difference between ball joint position on two otherwise identical wishbones could be as much as 5mm... doesn't sound alot, but when geometry is measured in fractions of degrees, it really does matter :y
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Thers a pic in the guide, handling etc in FAQ iirc.
Shows loss of control of the pivot position on a failed bush (again this doesn't apply to poly. Plus variations in dimensions, slop in the bolt holes, for and aft, and left right.
I did a test myself once, refurbished a polyed wishbone by replacing the rearward bush. Then set up. Same ball joint, same metalwork, same poly (and same car obviously ;D )
Camber needed adjustment from 1.40 odd on one side, and a slight tweek on the other I can't remember how much.
No way I'd run a set of tyres at 1.40. (Even though that's irmschers recommendation) Plus tramlining increases with increased camber.
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Good points, gentlemen. Castor angle cannot be adjusted, camber angle can, but on a Mcpherson strut/wishbone system it varies with depression of suspension and roll of vehicle, so must be a compromise. Toe-in may vary slightly with change of wishbone, if out at all will cause immediate problems with feel and steering, requiring correction. Rear end geometry is not changed with change of wishbone.
On a happier note, when I changed the nearside wishbone on OE03 EWW last Saturday I came to no harm, not even a bruise. MY dear wife assisted by heaving on a pipe to lower the new wishbone to enable me to insert the pin into the hub, and seems to have pulled a muscle or bruised a rib. Oh dear, I must get a longer pipe next time. Is there a better of doing it?
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Leverage is about the only way for that... weighing 17 stone invariably helps ;D
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Castor angle cannot be adjusted
/Panto mode on:
Oh yes it can
/Panto mode off
Whomever told you it couldn't is incorrect I'm afraid.
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How is the castor angle adjusted?
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By moving the subframe :y there's about 10mm scope at each of the six subframe bolts...
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I ain't trying to be funny but you would buy a pair of shoes not just one :y
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Castor angle cannot be adjusted
/Panto mode on:
Oh yes it can
/Panto mode off
Whomever told you it couldn't is incorrect I'm afraid.
Indeed it can. ...and it was me that told wim as much as well. ::)
Remember, the open day?
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Good points, gentlemen. Castor angle cannot be adjusted, camber angle can, but on a Mcpherson strut/wishbone system it varies with depression of suspension and roll of vehicle, so must be a compromise. Toe-in may vary slightly with change of wishbone, if out at all will cause immediate problems with feel and steering, requiring correction. Rear end geometry is not changed with change of wishbone.
On a happier note, when I changed the nearside wishbone on OE03 EWW last Saturday I came to no harm, not even a bruise. MY dear wife assisted by heaving on a pipe to lower the new wishbone to enable me to insert the pin into the hub, and seems to have pulled a muscle or bruised a rib. Oh dear, I must get a longer pipe next time. Is there a better of doing it?
Are these statements or questions Terry ? ;D
Set up is very much a compromise. :y Ride height is so important on these, as the camber changes with suspension movement. Wishbone pivots on an inboard radius and that radius pulls the wb ball joint inboard and outboard on bump and rebound. That's why the front tyres wear the edges. :)
Re set up. Once camber has moved, toe automatically needs adjusting due to the hub leaning in or out, the track rod then needs adjusting in or out to match. ;) likewise, if the caster is moved, then that moves camber by default, and then toe.
Therefore the order of adjustment is, caster, camber then toe.
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Re fitting the ball joint pin, it's very much easier with poly fitted, as there's no resistance from the front poly bush, unlike the stiff rubber of the oe ones. Otherwise, leverage is your friend.
I use the the "long pry bar in the wishbone hole" method, to lever it down, then tuck the pry bar under your knee/behind your leg. That frees up your hands.
I find the key is to pull the pin out so it leans as far outboard as possible, at an angle. (A stiff ball joint is key to this, if its loose or worn then the rubber boot moves the pin upright and it becomes much more awkward.) That also gives a fraction more room, then get the hub hole on top of the pin, then if you push the strut leg inboard on the right plane it just pops in when the ball joint pin is at the right angle.
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At first i would agree with t.paget that why should you have to have camber and the rest checked because of changing wishbones after having read all the articles on changing wishbones put on here by people lots wiser than myself i can now see why you have to,as stated no two are the same and therefore tolerances could be different and would put the measurements out thus wear on tyres and strange steering effects..Ali said would you just buy one shoe instead of a pair ????? well you may do if you have an artificial limb as that side would last longer than your normal side as the normal side takes all the pressure to steady you as you walk on the artificial limb so less wear on the artificial side ::) Also i was considering doing the job myself however as i do not weigh 17 stone and i am getting on a bit in life i think again i will pass that one on to my friendly local garage..So just goes to show how informative this forum is and all the info on here is free,now you cant get better than that, :y
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If your getting a garage to do the work, and their fitting bones with oe bushes, do make sure they tighten the front wb bolts with wheels loaded.
....NOT WITH WHEELS HANGING/CAR IN THE AIR.
Front bolts must be tightened with the car sitting at the normal ride height. :)
(Does not apply to poly)
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thank you Dr gixer...noted and I will make sure he does just that. :y
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Re fitting the ball joint pin, it's very much easier with poly fitted, as there's no resistance from the front poly bush, unlike the stiff rubber of the oe ones. Otherwise, leverage is your friend.
I use the the "long pry bar in the wishbone hole" method, to lever it down, then tuck the pry bar under your knee/behind your leg. That frees up your hands.
I find the key is to pull the pin out so it leans as far outboard as possible, at an angle. (A stiff ball joint is key to this, if its loose or worn then the rubber boot moves the pin upright and it becomes much more awkward.) That also gives a fraction more room, then get the hub hole on top of the pin, then if you push the strut leg inboard on the right plane it just pops in when the ball joint pin is at the right angle.
Thanks Chris, two good tips there.
In the past I have done it with my knee over the lever, but it's tricky. I find it easier with the wife on the lever. She probably won't do it again.
Next time I shall make a point of having the pin pointing outwards when inserting it into the hub.
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By moving the subframe :y there's about 10mm scope at each of the six subframe bolts...
Thanks. I imagine the top strut bearing is fixed, so the adjustment is by moving the subframe fore and aft. I'll wager it's quite stiff after 12 years of rust, not very critical, and hardly ever out of specification. WIM can measure it, but I wonder how often they have to adjust it. Does WIM give members before and after data?
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By moving the subframe :y there's about 10mm scope at each of the six subframe bolts...
Thanks. I imagine the top strut bearing is fixed, so the adjustment is by moving the subframe fore and aft/ and left and right. I'll wager it's quite stiff after 12 years of rust, not very critical, and hardly ever out of specification. You'd be surprised... WIM can measure it, but I wonder how often they have to adjust it. Have tweaked mine twice, once pre and once post frontal prang. Does WIM give members before and after data? Yes
:y
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By moving the subframe :y there's about 10mm scope at each of the six subframe bolts...
Thanks. I imagine the top strut bearing is fixed, so the adjustment is by moving the subframe fore and aft/ and left and right. I'll wager it's quite stiff after 12 years of rust, not very critical, and hardly ever out of specification. You'd be surprised... WIM can measure it, but I wonder how often they have to adjust it. Have tweaked mine twice, once pre and once post frontal prang. Does WIM give members before and after data? Yes
Thanks, Al. I stand corrected, enlightened, and impressed.
I accept after a front end prang all settings should be reset.
Last night on TV I saw a clip from 'Easy Rider' with the motorcycle front forks at a very strange castor angle. Or have I got the wrong angle?
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Does WIM give members before and after data?
Absolutely.
I've had to have the castor adjusted on 2 of mine before, unsure if that was because it had shifted, something had bent, or ze Germans didn't bolt it together accurately when they built it.
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Does WIM give members before and after data?
Absolutely.
I've had to have the castor adjusted on 2 of mine before, unsure if that was because it had shifted, something had bent, or ze Germans didn't bolt it together accurately when they built it.
The amount of play in those holes gives plenty of scope for huge variances. Ask wim, or any set up company. Production lines don't allow time for piddling about measuring fractions of a mill. It's all designed to be bolted together easily and on time.
Although more expensive marques are getting better. I'm sure you've seen new Astons at wim getting set up prior to final delivery.
If I had a new car, first thing on the list, get it set up. No way would I trust production line tolerances.
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Re fitting the ball joint pin, it's very much easier with poly fitted, as there's no resistance from the front poly bush, unlike the stiff rubber of the oe ones. Otherwise, leverage is your friend.
I use the the "long pry bar in the wishbone hole" method, to lever it down, then tuck the pry bar under your knee/behind your leg. That frees up your hands.
I find the key is to pull the pin out so it leans as far outboard as possible, at an angle. (A stiff ball joint is key to this, if its loose or worn then the rubber boot moves the pin upright and it becomes much more awkward.) That also gives a fraction more room, then get the hub hole on top of the pin, then if you push the strut leg inboard on the right plane it just pops in when the ball joint pin is at the right angle.
Thanks Chris, two good tips there.
In the past I have done it with my knee over the lever, but it's tricky. I find it easier with the wife on the lever. She probably won't do it again.
Next time I shall make a point of having the pin pointing outwards when inserting it into the hub.
You want to rent her out to OOF members mate ;D ;D ;D
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Does WIM give members before and after data?
Absolutely.
I've had to have the castor adjusted on 2 of mine before, unsure if that was because it had shifted, something had bent, or ze Germans didn't bolt it together accurately when they built it.
The amount of play in those holes gives plenty of scope for huge variances. Ask wim, or any set up company. Production lines don't allow time for piddling about measuring fractions of a mill. It's all designed to be bolted together easily and on time.
Although more expensive marques are getting better. I'm sure you've seen new Astons at wim getting set up prior to final delivery.
If I had a new car, first thing on the list, get it set up. No way would I trust production line tolerances.
This thread is proving very instructive to me, I thank all the experts for their advice. It is fascinating to learn that cars straight from the factory need setting up properly to drive well.
I have not researched this at all, but I wonder how critical castor angle is. Easy Rider bikes show it can vary by many degrees and still not make bikes unrideable. Camber angle varies with suspension movement so may not affect feel and handling much. Toe-in is the setting that is critical to handing and feel in my experience.
I run a six Omegas fleet for my family, seem to change about two a year buying on e-bay, and they all seem to feel and handle the same. If a new one feels wrong, after checking the tyres first thing I do is reset the toe-in with steering wheel central at straight ahead, if still dodgy I check wishbone front bushes and ball joints, changing when necessary. We do not race or rally our Omegas, just drive around in them. They are all end of life cars, way beyond their 7 year design life. They provide my family with cheap, reliable, luxurious transport. My point is that I have never had one that seems to be particularly awful in feel and handling, or especially good. Perhaps we are not very critical.
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Start chucking them around and the tyre wear will soon highlight any geometry discrepancies :y
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For the sedate driver, all geo angles - camber, castor and toe on Omegas - will show with uneven or high tyre wear, pulls, or a willingness to seemingly turn better one way than the other.
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Does WIM give members before and after data?
Absolutely.
I've had to have the castor adjusted on 2 of mine before, unsure if that was because it had shifted, something had bent, or ze Germans didn't bolt it together accurately when they built it.
The amount of play in those holes gives plenty of scope for huge variances. Ask wim, or any set up company. Production lines don't allow time for piddling about measuring fractions of a mill. It's all designed to be bolted together easily and on time.
Although more expensive marques are getting better. I'm sure you've seen new Astons at wim getting set up prior to final delivery.
If I had a new car, first thing on the list, get it set up. No way would I trust production line tolerances.
This thread is proving very instructive to me, I thank all the experts for their advice. It is fascinating to learn that cars straight from the factory need setting up properly to drive well.
I have not researched this at all, but I wonder how critical castor angle is. Easy Rider bikes show it can vary by many degrees and still not make bikes unrideable.slooooow steering on a bike, hard to turn but wants to fall to the side at slower speeds. On cars, not sure but similar sensation on steering, with the added effect on cantering the steering wheel out of a turn. I forget which way round, I guess the contact patch being wider than on a bike means the more raked out it is, the more then pc entering effect.
Camber angle varies with suspension movement so may not affect feel and handling much.
camber is taken as a static measurement and its assumed this is the same at speed as an average. Obviously there's pitch for and aft on the brakes and body roll in corners, but it's the static measurement that's used as most of the time the car is at a constant speed on a straight road.
Toe-in is the setting that is critical to handing and feel in my experience.
Actually, I find, and it's generally accepted that, camber is far more intrusive on basic handling*, especially as the tyre wears to that setting. It starts off leant over so wants to turn. Then as it wears it becomes cone shaped, or "geared" as the guys at Dunlop call it, so then it wants to turn even more. Add in road imperfections that affect the contact patch of that geared cambered wheel and tyre, and the fact that that contact patch won't always be the same on both sides, (you then have uneven performance a across an axle;) ) then things become very lively indeed, especially towards the end of a tyres life. Then add in an enthusiastic driver to accelerate that tyre wear process and it can all go tits up before the tyre is worn in the middle, as the edges are scrubbed off the tyre becomes round in profile due to camber deflection with different ride heights. Basically the directional stability of the front tyres are lost and the things tramlines all over the place. Which I hate.
I run a six Omegas fleet for my family, seem to change about two a year buying on e-bay, and they all seem to feel and handle the same. If a new one feels wrong, after checking the tyres first thing I do is reset the toe-in with steering wheel central at straight ahead, if still dodgy I check wishbone front bushes and ball joints, changing when necessary.
Have a look here :) http://www.omegaowners.com/forum/index.php?topic=90492.0
We do not race or rally our Omegas, just drive around in them.
see * below
They are all end of life cars, way beyond their 7 year design life. They provide my family with cheap, reliable, luxurious transport. My point is that I have never had one that seems to be particularly awful in feel and handling, or especially good. Perhaps we are not very critical.
possibly, but IMO these cars are indeed past their best, as you say, but that's not to say that's a situation that we should accept if we don't want to. The metal structures last well enough. The parts that are important for handling are the squidgy bits. Bushes mainly, on wishbones and rear donuts in the sub frame make the best improvements in accurate straight line handling, shocks and springs, set up and tyre wear, or more accurately tyre profile
* in almost all cases, handling starts with the simple task of driving in a straight line IMO. I'm not talking about cornering at all. Not even slightly. In fact, I rarely have an issue in corners with omegas at all. It's always straight line stability that cause the problems, as in the link. Therefor handling is nothing at all to do with performance or sport driving :)
Made a bollards of that, sorry.
Hopefully the quotes are deciephrable.
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Which brings us round neatly to the two millimeters of play in the steering box between left and right... Which isn't generally an issue, but which will significantly compound any issues resulting from worn components and whimsical geometry settings...
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....and doesn't allow a quick steering set up due to the reverse friction inherent in all steering boxes that causes a slow centering steering action. So dictates a castor setting to suit, ime. Not quite as bad as Mercs though.
Is yours a box Al?
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A rack :y I guess summat to do with V8 downpipes...
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My thanks to Chris for his comprehensive response to my note, and the reference to feeutfo’s essay on setting up Omegas., which I have read several times.
As described two years ago, I have devised a quick, accurate and reliable method of setting toe-in precisely with the steering wheel central. I know Chris and Al do not approve of it, but it has never failed me, or damaged a wishbone. Sassenach approved it, bless him, ruling the wooden block unnecessary.
I did once try to adjust camber angle. I could only do it with the wheel off, using a long lever to move the hub with the screws loosened. In no way was it a precise adjustment, and only measurable when I had replaced the wheel and lowered it to the ground. I wonder how WIM do it. Does anyone know? Perhaps I could do it with the wishbones supported as for toe-in setting, using the wheel as the lever.
Take it to WIM Chesham, you will say. In the last six weeks I have struggled three Omegas through MOT tests. All three needed new trackrods and/or wishbones. A split trackrod gaiter means a fail these days. It all means effort and expense. Traipsing over to Chesham and paying WIM £100 every time goes against the grain.
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Traipsing over to Chesham and paying WIM £100 every time goes against the grain.
Seek and thou shall find: http://www.blackboots.co.uk/tyre-fitting-centres.php
Nearest to you are: http://www.fcmwheelalignment.co.uk/# in Bristol, or: http://www.carsontyre.co.uk/ in Melksham.
Both WIM-approved, who'll use WIM specs.
;)
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£70 if mentioning OOF discount.
But even so I see your point.
However bending wishbones aside, there's no way to judge the accuracy of any procedure until you've encountered and compared against the bench mark.
Its a bit like cam belt locking kits. A lot of people say changing a v6 cam belt can be done without a locking kit. Which is true, it can indeed be done. I've done it myself pre forum days as I didn't know any better. But having now used the v6 locking kit obviously, I can tell anyone who asks that it is a great deal easier, quicker and more accurate more importantly to this conversation, than not using it. Its a no brainer.
Applying that to your situation, conversely I don't know how your going about your set up as I've not seen it, it might be spot on, but the comparison applies where your good self hasn't seen the alternative of the v6 locking kit when it comes to geo set up. The hunter hawk computerised rig that wim use.
So as a practical man such as yourself I'm sure you can appreciate our pov in that we can't really agree with you as a general recommendation to people here as a rule.
Everyone's situation is different and I sympathise greatly with anyone running more than one omega. One is enough for me. But I do think the phrase don't knock until you've tried it applies Terry tbh. :)
The main immediate gain from set up is to save tyre wear. Arguably the second consideration is handling and feel of the car to the driver. So given that your fleet has never seen set up, and especially camber is unmeasured, I personally feel an amount of concern, and would urge you to try set up at least once. Take your worst handling car with worst tyre wear maybe?
Even if its a local company?
Trust me though, there is no loyalty to wim here other than to repay the help they have given us over the years. We don't recommend them for no reason. Granted there's a few exceptions who have been unhappy, I've had agro meself getting the steering wheel central. But again, we can't really apply a general rule to very individual cases such as yours with so many cars. I sympathise greatly.
There is a camber setting guide btw, if you've seen it? Key is to get the correct tension on the camber bolts to allow movement without slip.
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Whilst I fully agree that suspension parts should be replaced in pairs, the standard of our roads has seen an increase in single wishbones being changed due to pothole damage. DIY'ers like us will replace in pairs due to set-up costs but garages won't, they'll replace just the damaged/worn one. :-\
Not ideal having different age wishbones on your car as it throws up future problems but it is happening. :)
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WIM use a ramp and jack the end they are working on... every adjustment is made with the wheels on :y
Whilst it does seem alot, a misaligned Omega can destroy a pair of tyres in days, so the cost is relative imho, and should be treated as a service point and budgeted accordingly :y
Terry, perhaps it would be prudent to get your cars MoTd early in order to stagger them, so you have an MoT to worry about every two months rather than all together... this would spread the workload and costs more effectively :-\
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....sorry, re camber guide, i should be clear.
It does rely on the original setting being somewhere near correct. So its more for replicating the original setting, rather than finding the correct setting.
So firstly there is no way of finding the correct setting to within tolerance without geo set up. The Hunter rig takes calculations that allow the the operator to measure the settings at normal ride height, then work out the new adjustment with wheels hanging. The final check is then made when the car is lowered to normal ride height again.
Secondly, this might be a way forward for you, given your happy to drive a non set up car, in that perhaps its worth setting up one car so you know its correct, then looking at ways to measure that car and transfer those settings onto the others...?
After all, if your happy with the tyre wear and the way it drives, ultimately, why worry. But you may well find that the car drives better and the wish you'd had set up done before.
I certainly find it frustrating if the car isn't quite right, that I've missed the performance on the life of the tyres up to that point.
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Traipsing over to Chesham and paying WIM £100 every time goes against the grain.
Seek and thou shall find: http://www.blackboots.co.uk/tyre-fitting-centres.php
Nearest to you are: http://www.fcmwheelalignment.co.uk/# in Bristol, or: http://www.carsontyre.co.uk/ in Melksham.
Both WIM-approved, who'll use WIM specs.
;)
Thanks Seth. The Bristol outfit looks most competent, good website and will do 4 wheel alignment and adjust toe-in for £25. Not far from Vauxhall Direct in Avon Street, my nearest , trade club source. I must make contact.
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Whilst I fully agree that suspension parts should be replaced in pairs, the standard of our roads has seen an increase in single wishbones being changed due to pothole damage. DIY'ers like us will replace in pairs due to set-up costs but garages won't, they'll replace just the damaged/worn one. :-\
Not ideal having different age wishbones on your car as it throws up future problems but it is happening. :)
Was more of a problem buying unknown e-bay wishbones. Now I buy ATEC wishbone/trackrod/droplink kits, and they are much better.
On one occasion son Jonny's car passed its MOT, but driving it home I did not like it, steering twitched on braking. I traced it to front wishbone bushes, so changed both wishbones before returning the car to my son. So I will change wishbones if there is a fault in them. In the current case I changed one wishbone, tested it under braking, no twitch, so I accepted it.
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I learn from the FCM website about the various steering parameters. Caster angle, if positive, make for heavy steering; if negative for light but twitchy steering; main requirment is that it be the same both sides, or steering will pull one way; no effect on tyre wear. Camber angle, if wrong, can cause uneven tyre wear side to side; no effect on handling. Toe-in, measure of how parallel the front wheels are, affects tyre wear, stability, handling, and is critical.
I learn from Al and Chris that WIM do all their measurements and settings with wheels on and suspended, to calculated settings, then check settings with wheels lowered and load bearing. Fair enough. Better than the tyre shops and garages I have seen setting toe-in with the wheels on the ground, or even on a ramp on greased pads, adjusting just one track rod.
I agree with Chris I should take a car to FCM Bristol and have it set up just to see how a well set up car feels. But just now I have to get KR02 SRO though its MOT. It needs a new exhaust system for a start.
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It's worth noting that a decent workshop will gladly talk you through any given task. WIM for example, are happy to explain what is happening as each adjustment is made. This is because they take pride in what they do and treat questions as a chance to explain things :y
What makes this refreshing is that alot of places react negatively to questions because they suggest you aren't happy with summat and treat them as a slur on their work rather than keen curiosity...