My S has developed an irritating knocking noise. From behind.

Not metallic. Seems to be more obvious at low speeds and when going over road irregularities & bumps. Also more obvious on decelerating and breaking - but might just be that I can hear it better over my exhaust when the throttle is off. Sounds hollow, not regular like a wheel bearing or stone in tyre, a bit willy-nilly.

Got eibach springs, megan rear toe arms and T1-R driveshaft spacers on, if that lights any bulbs?

Any ideas?

 

How are the dampers? Is it just from one side?

 

My dampers have 60k on them. Ride is just as firm as it was - probably firmer if anything. I thought they get squashy with age?

Think the noise might be from the rear passenger side but cant be sure...

 

Sounds like ARB bushes to me

Is it a more of a clunking sound/rattling sound then disapears?

 

or my old favourite, drop links

Get under the car and try to rattle the ARB.

 

Hmmm I'll try. Would make sense as it's only when one side (left) goes over bump. Will give it a go tomorrow.

If it is the ARB, do the cusco ones come with bushes, as it would be a good opportunity to upgrade at the same time.

 

Drop links maybe, but I think most ARB re use the oems anyhow.

Check the Megan rose joints for play orl seizure, they will clunk.
Normally when moved significantly, like a speed bump or as you describe.

Also check the Megan toe arm nuts for tight.
Losse nuts happen and then you get play in the threads and clunks.

I noticed it more backing out of the garage and dabbing the brakes as the back moves a lot more.

HTH.
Steve