Random knocking

[adrian1956]

I'm running a 850SE estate...which has a random knocking, I think from the drivers side front, it comes and goes and although I thought it was a replacement top strut mount (replaced a while back) I then recently changed the front suspension struts/springs/mounts as a full kit (which I thought had stopped it!) BUT...it's back, I ran down to North London, it was doing it in traffic on the M1, I pull into the services to check everything ...gone!, on the way back it did it for 10 mins...then fine when we went the Heathrow, on the way back it did it for 10 mins. Today, went 20 mins in traffic all fine, then 3-4 mins knocking and fine again on the way back. Anyone have any ideas! A.

[ASt85]

Assuming you've already replaced the drop links and as you've replaced the suspension struts, springs and mounts top mounts, it might be worth having a look at the bottom ball joint.

Jack the car up and check for play using a crowbar. Whilst your at it check the track rod end as well. The other possibility is perished sub frame bushes, which can sometimes produce really odd erratic knocks as well a "sloppy" steering.

[Stu B]

Mine was doing similar, even after replacing strut tops, spring seats, dampers etc. and it turned out to be the ARB drop links (I'd put back the old ones as they looked ok, but once disturbed knocked intermittently).

I got some Meyle HD ones via eBay, a pair inc. delivery for about the price of one from other suppliers. I can find the link if it helps. Some info in this thread, post 9:
https://www.volvoforums.org.uk/showthread.php?t=273249

Other thing, as above, could be a bottom ball joint or lower arm bushes, again I had similar and replaced the lower arm with those bushes and joint complete.