My volcano RS2 Avant

[Avantus]

Help, my front suspension is knocking again

when driving over very rough tarmac at low speeds it's really knocking like hell.
I've traced it down to the topmount area, but I've got no idea what could be wrong??

I've mounted H&R coilovers with new topmounts. I've only re-used the slotted nut, but that can't be any tighter. When I lean on to the front fenders and give it some short pushes, I can hear it knocking, and also feel it when holding my hand on to the top of the shock absorber. Also when shaking the tire violently in camber-direction, I can hear it knocking.

So in my opinion there is too much play in the topmount area? But it's all tightened down and checked a million times, like all the rest of the suspension, just to make sure.

What I did notice when mounting up the front struts with the H&R kit, is that when having the topmount bolted down, it was still sitting loose and I could not only turn it (which ofcourse it should), but also shake/twist it.

Would be thinking of some alternative topmounts, but I can't figure out what could be wrong with this setup. Maybe the upper spring-cup of the H&R kit that isn't compatible with the original topmounts?

[Jamo]

Sounds like the anti roll bar drop link, happens all the time, give them a wiggle if it's gone it will have a lot of movement and a knocking sound

[Avantus]

Those have been checked and are OK, even took them off to make sure

[Avantus]

I've tried tightening down the 2 slotted nuts a bit more, but they are getting pretty worn now...

strange thing is that I hear and feel the knocking when pushing down on the wheel-arch, but when I turn the shock a bit with the inbus key, it sometimes stops.... it wouldn't be those worn slotted nuts that have play and thus are causing the knock?

Also when pulling the engine left/right, and with one hand on the thread of the shock, I can feel it clicking/knocking. So really must be something with little play.

aaargh, one of those love/hate days

Will have to get the old spring compressors out again, to take a look at it I guess...

[AndyP]

Top mounts should be classed as consumables on these cars, just change them with every oil change and you'll be fine!

[macspring]

I have the same annoying rattle from the front end, wishbone bushes and ball joints, track rod ends are all fresh, new top mounts, also new drop links improved it, but then I thought I nailed it when I found the catch on the underneath of one side of the bonnet was loose allowing it to rattle.

Adjusting it and then tightening it improved the “rattle" but still there. Don’t think it is the bushes on the inner end of the steering arms at the rack.

I am thinking about the rack needing adjustment, but only 130k on it, the other item might be either of the wheel bearings.

Sorry for the hijack, but thought the bonnet catch being loose might help someone with a front end rattle on bumps.

Keen to see what your cause turns out to be.

Kind regards.

[andy10v]

[QUOTE=Avantus;626736

What I did notice when mounting up the front struts with the H&R kit, is that when having the topmount bolted down, it was still sitting loose and I could not only turn it (which ofcourse it should), but also shake/twist it.
[/QUOTE]

Could you add a washer to allow it to be clamped?

[Avantus]

I was also already thinking that adding a washing between the bearing of the topmount and the upper springcup might be a good idea.

On the H&R kit the upper cup is lined up with the top of the shock absorber, but the bearing doesn't cover the total width of the cup, so maybe the play is coming from there.

I've fubar'd my slotted nuts in an attempt to tighten them down even further, so I'll start with 2 new ones. Doubt now is if I'd be better of to ged rid of my 500mile old meyle HD topmounts.

Simply pushing down onto the fender with short pushes and one hand on the thread of the shockabsorber is enough to feel that "click", so I'm pretty sure it is topmount area related!

thanks for thinking with me all!

[macspring]

Ask someone to post up a “kate” picture of an S2’s front strut assembly to verify the bits that are supposed to be there, and in what order, from the factory.

It may help you to decide where and what thickness, number of washers etc. to add in an effort to eliminate the play.

Someone on here may even have real photos of their strut as they assembled the various pieces.

Nothing worse that play / rattle that cannot be traced.

[Avantus]

I'm pretty certain that everything is mounted in the way it should be.

Something that would be possible is that the upper spring cup has gotten above being level with the top of the shock (where the thread begins), and that with every compression (like pushing on the car) the topmount is pushing the springcup down.

Difficult to explain it in words, but that's the only thing I can come up with for now.

[Avantus]

Going to take it all apart tomorrow, and mount it again with new slotted nuts.

One thing someone advised me to check is: aren't the upper coils of the springs in front grinding against eachother? That could well explain why I can feel a clunk when pushing on the fender. Anyone else has had that?

Could try with putting some cloth in between the upper and lower coils, to see if they aren't my cause for the heavy knocking.

edit: coil binding is the correct term it appears

[Avantus]

And here is the bearing of the topmount with the upper springcup. Top of the damper needs to be aligned with the springcup, so that the bearing touches both, but maybe a washer underneath the bearing is a good idea?

[andy10v]

So does the spring perch not sit on the step on the damper?

[Avantus]

it can slide on the damper, being pushed against the bearing by the pressure of the spring.

So perhaps my bearing wasn't tightened firm enough from the beginning, so that the spring-perch got up a bit (above level with the top of the sleeve of the damper on which it slides) , and that now on every compression the topmount+bearing pushes the perch down a bit, until the bearing touches the damper again.

[andy10v]

Hmm, on the factory setup the spring perch is clamped onto the step on the damper.