Knock



  • chaps…i know this is a bit general, but I was hoping you might have some suggestions.

    for a while now, I have had a "knock" under the car. Seems to occur when the car lunges forward, such as under braking, and when the car lunges back, under acceleration. Its just a single knock each way....what could this be?

    Shock? It feels and sounds, like its nearside front. I have done the discs and pads recently, but it did this exact thing before that, but im open to suggestions regarding the brake anti rattle kit, im not 100% sure i have the full anti rattle kit on there?

    what else could it be, engine mount??



  • could be a worn driveshaft or similar. mine does this too but its worse when reversing then braking.



  • hmm…worn drive shaft? even though it only seems to happen when the car actually dips down or rises up?

    how easy is it to replace a driveshaft?



  • Engine or Gearbox mount? Mine knocks when starting off… and I think it's the Gearbox mount...

    Does yours knock over rough ground or speed bumps?



  • yeah it seems to, but the knock is more pronounced on stopping/starting off, almost as if something is popping into place out of place. I was thinking shock absorber…?



  • I would check shocks… I would say shocks over driveshaft... but ould check the mounts too as start/stop knock could be engine movement in knackered mounts.



  • cheers Hammy.

    actually…with regards the engine mounts, the one at the front MIGHT be to blame. When I had to remove my rad and air con rad, I had a quick look, and it looked slightly bent, are these easy enough to replace? I assume jack engine up, remove mount and replace?!



  • Front and side mounts are easy, if its the one at the back that is an absolute biatch, even to see.

    Easy way to see if its an engine mount is load it up, keep the foot hard on brakes and let clutch out to drop revs ( not stall it) in first and reverse, if it clunks and goes nowhere its defo an engine mount

    Shock test just bounce car up and down by hand you should here it at some point

    If neither of those look at bushes and ball joints and possibly even CV joint :wink:



  • cheers Marco, going to have a proper look this weekend. It isnt as bad as it was before I did my brakes, so im 90 odd percent sure its the shock absorber…will do the bounce test as you suggest!



  • CHAPS!

    ok, I need to revive this thread pronto!! I did some investigation this weekend (been busy driving works Lotus Exige S ) and I found this!

    so, what think ye?



  • Is that a droplink?



  • That is a ARB droplink yes, if you can undo one end of it you can give it a wiggle to see if its goosed or not. new ones have no play and are very stiff to move.

    when worn will usually knock going slow over small bumps and on full lock when slow cornering,



  • its not the drop link….I dont think anyway, what about the movement in the drive shaft??

    here is another video to indicate the noise. Here, I am simply turning the steering wheel full lock both ways



  • that sounds like either driveshaft or CV joint to me and i would be tempted to say its the latter of the two. very similar noise to when my CV joint went on my old 3



  • hmm..has to be one of the two, but what about the fact that I can move the drive shaft back and forth? does that indicate ourter cv, or inner??



  • i would say the inner near side CV joint, luckily they are not too expensive. I am sure someone else will be along with their expert opinion but that would defo be my guess mate



  • thanks Dan

    it does seem that way, as I can push the driveshaft up first, then back. I did inspect the boot, and it doesnt look split or anything but i wonder if, regardless of the expense, its better to replace the whole thing?



  • if in doubt (which is possible as even my mechanic couldnt tell which one was gone) replace both inner and outer. sorted my problem out. I need to do it again on my new (older) one now though :(



  • cheers dude, I think thats the best course of action. I will get a new one ordered as son as I can find one at a decent price. Probestore is a bit dear…...



  • europarts or mill autos are pretty good, if you find a cheaper price with them message ROC on here (probestore) and see if he can beat the price ;)


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