Knocking/rattling from rear coilovers

[boggissimo]

I have recently had a full set of HSD monopro coilovers fitted to my blob wagon.

I picked them up secondhand, and had to replace the dust boots and springs on the rears, as one had a crack. Just after they were fitted I started to hear knocking/clunking sounds coming from the rear, and had a look on forums etc and called up Driftworks (who are the UK suppliers of HSD). First thing to check was that all locking rings were tight (they were) and that the top nuts were also tight (they were, and I used impact wrench to make sure). I didn't change any bushes/droplinks when the coilovers were fitted and the guy at the workshop said they all looked OK - though I can imagine that the stiffer springs will show up any defects eventually.

The noise is a knock/rattle when moving (whether in gear or not, whether under power or not), is not there when I first drive off, and starts after 5-10 minutes of driving, which suggests that it's not something loose. My main suspicion is the dampers themselves, which Driftworks will sell me at £110 a pop to replace, but I want to exhaust all options first.



Anyway, before I bite the bullet and replace the dampers, does anyone have any other suggestions for what I could do to eliminate any other causes of the knocking sound (adding grease/lube somewhere?), or whether being on a wagon means they should have different/adapted top mounts or something?

Cheers

[Ginola]

Are the springs are pre-loaded enough? assuming this happens when you go over bumps?

As Driftworks said make doubly sure all the locking rings are tight, particularly the bottom ones if height adjustable from bottom of coil over.

The standard struts are very prone to knocking due the angle they sit at.

[boggissimo]

Originally Posted by Ginola

Are the springs are pre-loaded enough? assuming this happens when you go over bumps?

Thanks, I haven't adjusted the pre-load, Driftworks said to set it so the springs were just held, not tighter. Might give that a try.

Have checked everything is tight but I suppose they might have worked loose - but then they'd be knocking from the moment I set off, not just after 5-10 mins of driving, I think.