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[Diamond Black Geezer]

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. 

[chrisgixer]

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.

[Diamond Black Geezer]

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

 

[chrisgixer]

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?

[Diamond Black Geezer]

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. 

[chrisgixer]

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?

[Diamond Black Geezer]

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. 

[Nick W]

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.

[chrisgixer]

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?

[chrisgixer]

And if anyone is using oe front bushes. Tighten with wheels loaded.

[Nick W]

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.

[chrisgixer]

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   [manto mode off]

[Diamond Black Geezer]

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 

[chrisgixer]

Aeye. Don't forget the angle tightening

[Diamond Black Geezer]

Will do 

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!