Technical Help me trace this knock (passenger footwell)

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Technical Help me trace this knock (passenger footwell)

Joined
Feb 15, 2007
Messages
2,189
Location
West Yorkshire
originally presumed it was coming from the geabox, but i want to cover all possibilities before i resort to getting the gbox overhauled. i had several reasons for presuming gbox but i just wanna make sure :)

Thing is, i havent been able to properly replicate the noise in the garage (otherwise itd be easy :) .) the only time i did manage to replicate it is by having the front end up on stands, putting it in second, taking it to 30mph and then hitting the clutch and brakes, then i get the knock as the wheels come to a quick halt.

another test i did was on our driveway. its on a slant and very bumpy, so i reversed it to the top and switched the car off. stuck it in neutral and let it roll down the driveway over the bumps while turning the wheel left and right. it knocked a couple of times but not half as much as driving it.

doesnt seem to be any play in wheel bearings or steering rack/track rods, wheels are on tight. bounced all four corners of the car to test suspension, no knocks. tried rocking the engine and check mounts and that seems to be secure and mounts in good nick. anti-rollbar and mounts look fine (rubbers starting to crack but no metal on metal contact.) exhaust not knocking (its a much more 'solid' knock noise than exhaust anyway.) subframe mounted securely. everything in engine bay mounted securely.

the knocking seems to happen when decellerating in any gear below about 30mph. I also noticed when driving over speedbumps i get knocking, but when i hit the bump with just the passenger side wheel, the knocking is far worse. Also it tends to knock more when cornering, so my assumtion is the knocking is much worse when the wheels are at different 'levels' and the weight distribution leans. If im driving on a smooth road and take the passenger side wheel over a grate, i get several knocking sounds.

So im thinking hopefully its CV joint or suspension arm. Are there any test i can do to confirm this? any other suggestions to trace the noise?
 
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a1ant

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Almost definately the rear bush on your wishbone. Just had this problem on mine.
 
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Joined
Feb 15, 2007
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well i had a look tonite, and although the bush looks fine, i replaced the arm with one from my old subframe. unfortunatly when mounting the anti-rollbar in place, i snapped one of the bolts. i suspected the other bolt had also be overtightened, and as i was reversing it out of the driveway, it sheared off aswell. i gave it a gentle test drive anyway, but to be honest i couldn't hear if the knocking was still there due to the clattering of the rollbar. Im gonna remove the rollbar altogether 2moro and give it a gentle run, see if the knockings still there. if its not, ill buy new arms. if it is, ill replace my old arms so i can remount the rollbar. then ill be stuck for ideas :eek:
 
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