Thud/clunk/knock from rear of car

[cnut]

I have done nearly 500 miles over the weekend and my car has developed a slight thud/clunk/knock from the rear when either pulling away in 1st and letting off the throttle or sometimes when braking to a halt. I accidentally stalled the car at standstill when I let the clutch out with the car still in gear (learner driver style!) but apart from that I can't think of any other incident I had with the car over the weekend.

The thud sounds like an exhaust knock when an exhaust rubber has gone loose but I have checked those and they appear to be fine. Any suggestions? It's a FWD so it won't be anything to do with the Quattro system.

 

[swarcup]

Have a look at the rear anti roll bar, there should be some plastic collars around it where it is held by the bushes, these collars can brake and fall off letting the roll bar move slightly causing a knocking. Its an easy visual thing to check. all the a4's are prone to this

 

[demus]

May also be the fuel in the fuel tank, when mine is a little over 3/4s full I get a thud, clunk from the back, just how the fuel sounds as it moves in the tank, only noticable occasionally when stopping or moving off...

 

[cnut]

Cheers fellas, I will get these checked out. The fuel in a tank is a new one to me though? I had a little inspection yesterday and it's definitely worse when in reverse. I'm just hoping it's something not too expensive but if it is the rear awb it would be rude not to go for an RS4 bar

 

[demus]

Have a nose around on tinternet, theres a few reports of it... see if it conicides with a fuel level

 

[marktdisport]

Mine does a thud that seems to be 3/4 of a tank, slow movering back and forth !!

 

[cnut]

I'm beginning to suspect the thud may well be coming from the fuel in the tank. I filled the tank up last weekend and it was loudest at 3/4 full now it's down to about 1/3 full and I'm struggling to hear it... I'm going to let it run dry and see if that stops the noise completely.