Hello, recently my car has been knocking over bumps. Mainly over small ones or drains etc. It's a single metallic clunk. I have had a look at everything in that area and used a pry bar on the bushes and nothing is loose or has any play. The shock is all good and so are the top mounts and bearings. Any idea what this could be? Sounds like something hitting the frame of the car. I did accidently undo a subframe bolt when I did the Controls Arms and don't know if these are stretch bolts or not. Could a loose bolt cause this kind of knock?

Appreciate any input

Has it got drop links on the ends of the anti roll bar, if it has it could be those knocking.?

I unbolted these and checked them and they have no play in them at all so I don't think it's them. Everything seems to be tight and no play. I have new engine mounts on aswell so I doubt it's that. Just seems weird how nothing is obviously loose or worn.

You can`t feel the play in those joints as it only occurs under tension, if they were loose enough to feel in the hand they would be close to failing, also check roll bar bushes as the knocking can transmit through the chassis and sound like its closer than it is.

Just a thought anyway

Is there any way of checking the rol bar bushes. Could I disconnect the end link on that side and go for a drive or would I have to disconnect both sides?.

You dont need to disconnect the roll bar. where the bar runs at the front of the chassis/subframe there are 2 clamps holding the bushes bar, if they look worn -split they need replacing

I wouldn't dismiss the drop links though as they are more likely to be the problem.

I have known suspensions to be replaced and cost a bomb because the drop links have been dismissed and they look good, and can't feel any play in the ball joints, they are deceptive, i would get them checked out imo.

Edited by Bolt on 26/12/2021 at 07:51

I had a rattle from my front end after I'd cleaned out and checked the brakes. It was a brake pad rattling in the caliper, the dust had muffled it.

You can also get pad knock when reversing, where the pad is low the pad/backplate takes up the slack of a few thousands of an inch, going in reverse and brake hard to stop and knocks as it does it, very common that is...

Got the wheels off today and had a look at everything. All subframe bolts are tight. I took the drop links off and drove the car round my block and it still made the knocking so I doubt it's anything to do with the anti roll bar. Checked all the bolts for the suspension and everything is torqued to spec. I did also check the brakes and they are secure with no room to rattle around. I'm thinking it might be the exhaust hitting the subframe or something.

Other possible is shock absorber knocking or bottom ball joint, if they are worn, problem is without hearing it, its difficult to say, but as you`ve checked and discounted the mentioned parts I would look at shocks/bottom ball joint next, though difficult to check those for knocks if ball joint has small amount of play it might be difficult to see/feel

I have taken the shock about and removed the spring and the shock is hard to push down with my hands so that's good and when I release it from the bottom it comes back up by itself. It comes up slowly but smoothly all the way back up. The top mounts are good with no splits or anything and the spring is solid with no cracks or missing pieces. I took the lower ball joint out aswell and it has no play up and down and feels alright. Might just be one of those noises I will never find until something becomes obvious

Just been out again and checking everything and when I put a pry bar between the knuckle and the lower ball joint there is very slight movement. I can't feel it clunking but it looks like the dust cover is moving up and down like there is a very small amount of play in the joint. Is this normal or would this be causing the knocking?

Got a new ball joint for tomorrow, will just have to drill out the rivets and put this new one on. The body of the ball joint housing was moving but the actual ball joint was solid in the knuckle, so the arm was moving up and down. Only by a couple of millimeters but its the only thing that seems to have any play. I also noticed that this morning when I first turned the steering wheel it was binding and then releasing. Would this be the ball joint seizing up? Couldn't feel any clunking through the top mounts when turning the wheel

I went and got a new wishbone this morning because it was only £25 more for the full arm. The old ball joint had a very small amount of play but also had a small tear in the boot. The new arm is on and the knocking has gone. Very happy bevause it was doing my head in. Thanks for all of the help and suggestions, I really appreciate it

Thanks for letting us know its fixed, any knock or rattle is annoying and some difficult to find, but glad your sorted, happy driving....

Glad you got it sorted Joe. Good to know what went down there, so one for the notebook : - )