Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Diamond Black Geezer on 07 July 2015, 09:58:47
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Knock Knock...
Who's there?
Suspension knock, under lateral load.
Not much of a joke, so here's the problem...
When traversing lumpy ground or making a sharp-ish snap left or right there's a clunk, like something kitting the end of its travel maybe, or a worn shaft in a hole, that kind of thing.
Front suspension all new or refurbished. Car's mileage is 178k, OS bearing done 37k NS original. Wishbones are GM and Poly'd bushed, and GM ball joints, the track rods and droplinks are ATP. Bilstein B4s. Strut top mounts done 37k.
All new parts now done nearly 3k only.
Upon further investigation I thought the camber bolts had come loose, these were re-torqued. (didn't own a suitable torque wrench at time of setting camber, do now)
Only thing I can think of that it could be is steering idler. I'm stumped. ???
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Has camber been set correctly?
Is the knock in time with wheel speed? Or in time with a bump? Or in time with lateral movement.
Did you grease polls? Had it got poly roll bAr bushes? Ditto grease.
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Its under lateral load - so straight line = silent; in a bend = can be silent; but a sharp snap of the wheel and back to straight ahead again will cause a knock.
Camber set 'approximate'
Knock not in time with wheel speed, as above.
Polys were greased on fitting
No Poly AR bushes
:)
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either something loose like wishbone bolts, or camber slightly too aggressive and allowing the inside wheel to touch the strut.
Any marks on the strut upright ? Would probably give a knock in time with wheel speed but if it's a sudden stab of lateral load it might be that.
How tight are wishbone bolts...? How many nm's applied
After thought. Is it large AND right turns?
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Wishbones bolts are all torqued (however more than happy to slacken off and double check them)
Like your thought regarding camber, will check for relevant marks.
Yes, I'd say a sudden right turn. Generally to do it I let the car drift to the left of the road, followed by a sharp 'twitch' to the right. :y
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If the knock us from the inside (of the turn)wheel then there's a good chance.
Obviously it needs setting up but you knew that, and are letting the suspension settle first. Right? ;) :y
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Cheers for the reply. A good chance of what? The camber being out, or the wishbone being loose?
I have the wheels set at 'all the way out, then in a little bit', as it were, so in theory no way they can be hitting the struts. But will double check that.
The knock appeared one day, weeks after the suspension was reassembled, rather than as soon as I rebuilt, so don't think it's any kind of settling issue. :)
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I've just fixed something similar on mine. Having tried all sorts of prying and checking, it turned out to be a loose wishbone rear bolt - I could turn it with a spanner, but not tighten or loosen it. Cranking it up tight with a good impact wrench cured it.
The NSF suspension on my car is always creating issues.
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I've just fixed something similar on mine. Having tried all sorts of prying and checking, it turned out to be a loose wishbone rear bolt - I could turn it with a spanner, but not tighten or loosen it. Cranking it up tight with a good impact wrench cured it.
The NSF suspension on my car is always creating issues.
And why didn't you tighten to the correct 120nm + 30+15 degrees? Hmm?
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And if anyone is using oe front bushes. Tighten with wheels loaded.
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I've just fixed something similar on mine. Having tried all sorts of prying and checking, it turned out to be a loose wishbone rear bolt - I could turn it with a spanner, but not tighten or loosen it. Cranking it up tight with a good impact wrench cured it.
The NSF suspension on my car is always creating issues.
And why didn't you tighten to the correct 120nm + 30+15 degrees? Hmm?
I had.
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I've just fixed something similar on mine. Having tried all sorts of prying and checking, it turned out to be a loose wishbone rear bolt - I could turn it with a spanner, but not tighten or loosen it. Cranking it up tight with a good impact wrench cured it.
The NSF suspension on my car is always creating issues.
And why didn't you tighten to the correct 120nm + 30+15 degrees? Hmm?
I had.
[panto mode on] oh no you opposing well hadn't ;D [manto mode off]
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Thanks for the inputs. I will re-torque the wishbones tonight, it's something to eliminate. May have done them to 110Nm... that's 'worst case scanario'... or they're torqued up right. either way, will be checking :)
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Aeye. Don't forget the angle tightening :y
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Will do :y
Only odd thing is I've never had issue with 'loose' wishbone bolts before. I confess, I've never gone down the torque and angle-tightening route before, just done them 'really tight' and then a bit more - and never had such a problem.
I can only assume (assuming that this is the problem) that now because my bolts are so new, as are the wishbones, and there's no rust in that general area to act like a sort of threadlock, that this is the cause.
More than happy to give it a go, though, for sure! :)
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They're either loose, or they ain't. If not, we'll think again. :y
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If you find nothing wrong, Spray some grease into the polys as best you can. If you have a spray grease can or copper shite spray can..?
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Ah, I've actually recently greased the NS (red grease, wasn't sure whether normal grease would corrode the poly as it does with rubber, so thought it safest bet) :)
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Ah, I've actually recently greased the NS (red grease, wasn't sure whether normal grease would corrode the poly as it does with rubber, so thought it safest bet) :)
It's what copper slip was designed for... hence why Poweflex supply a sachet of the stuff with the bushes :D
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Ahh, fair enough. The sachet of the copperslip is long gone (the polys were bought about 5 odd years ago, I nabbed them from the wishbones of Turbo Weasel I used to own) and therefore couldn't remember what kind of greasy substance was in the sachet. Will copperslip the OS tonight, then, save my red grease for rubber bits :)
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you dont say if its worse one way or the other? however a little bit outside the box try the brake caliper sliders,can get wear and they do knock
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Gentlemen, we have a conclusion :)
Went in for the tracking/geometry first thing this morning (that's another story) and asked the mechanic to have a look while he was under there aaaaand... traced it to the droplink.
Happy to say that it was literally a quarter turn on the nut and she's silent. Now I think about it the droplinks were probably done just before I bought my torque wrenches, so I would have done them 'tight' but not too tight. I know for a fact that the Halfords spanners are rather fat, and so tend to be clamped (to the point where you can't actually remove them) when you tighten the nut on the balljoint, hence the last 'nip has to come without the benefit of having a spanner to stop the balljoint rotating. He checked all the others while under there, and they were all bang on, so clearly just one fo those things. I'll make sure they're torqued one evening, though, to avoid further issue :)
Problem solved!
Oh, just to say, the wishbones are now torqued to OOF/Vx spec, including angle tightening, too :) As ever much appreciated, chaps :y :y
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Strange. Once in a bend, turning tighter still shouldn't give a drop link a chance unload and then load up again. There by giving the opportunity to knock. Unless the car goes through a level plain first the roll bar is way too stiff to allow the play to be heard, ordinarily.
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Tell me about it!
No ideal how that would be an issue under lateral load. Hence my putting such as droplinks way down the list of likely candidates, especially as they're new.
Also, why wasn't it knocking under general driving, and in straight line? Why only (apparently) in bends? ??? I'm not saying it never knocked when going in a straight line, but only on particularly rough ground, where all the suspension components are under considerable strain. I've always found that even the slightest little bump shows up a worn droplink.
So, unless the knock actually kicks off again, and that was just coincidence, at least I can sleep a bit easier - and got to Billing! :)