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Knocking noise

Posted: Sun Feb 19, 2023 1:34 pm
by lawro4156
Hi

Has anyone experienced an annoying knocking noise coming from the rear nearside of their caddy van?
It’s has new rear shocks I have checked they are still tight, rear drop links and anti roll bar bushes are all fine.
I can’t find the culprit anywhere!!
Any suggestions ?
Thanks


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Re: Knocking noise

Posted: Mon Feb 20, 2023 8:56 am
by Scoobysrt
Loads of threads on this, it's quite common. It can be a number of things from the anti roll bar to a shock top not fastened in.
When it had new shocks were they tightened up while the van was in the air or on its wheels? They should be tightened up when the van weight is on its wheels.

Check the exhaust.

Was it previously lowered and you've gone back to standard? If so are you sure it's on standard drop links?

Will it knock with someone bouncing in the back? If so get someone to do that while someone looks underneath.

When mine did it the top bolt of one of the shocks had come loose even though I was sure I had done them tight.

Is it very bouncy going over bumps? If so its a shocker.

Re: Knocking noise

Posted: Mon Feb 20, 2023 1:01 pm
by lawro4156
Hi
Thanks for your reply

The shocks were tightened whilst it was in the air, but I have checked them when it’s been on the ground and they are tight.
It’s never been lowered and still has original Anti roll bar bushes and drop links.

I have checked exhaust, spare wheel and they are all fine. It doesn’t knock when you rock the van but I will get someone to jump up and down in it whilst I look underneath. I’m guessing changing the anti roll bar bushes and drop links would be a good start to rule that out!?
Thanks

Re: Knocking noise

Posted: Mon Feb 20, 2023 10:40 pm
by Lockstock
I think you need to tighten them only when on the ground, as otherwise the change in geometry when placed on the ground will mean the pre tightened nuts and bushings will be under constant tension in a way not designed for, which they shouldn't be.

On my Volvo, this mistake with control arms can cause knocking noises and very premature failing of the bushings. I don't know the ins and Outs of the problems it causes on Caddy shocks, but them still being tight when lowered, might not mean it's not an issue. Someone more experienced will confirm I expect.

Re: Knocking noise

Posted: Tue Mar 26, 2024 7:07 pm
by 76roy76
I've the same knocking noise and I'm now beginning to think it's the side door rails causing it ? That's after checking everything else that I can see.

Re: Knocking noise

Posted: Sun Mar 31, 2024 10:04 am
by Rastamouse
I also have a knocking when I decelerate 😡