knocking noise from rear of car

[raj]

hiya I own a 325i cab and need some help when driving I can hear a knocking noise from the rear of the car (driver's side) any idea's what it could be thanks

[Nelly]

Rear subframe bushes need changing, rear top mount shagged, prop center bearing knackered??

[Falkster]

Easy one to eliminate is to drive down the road with your handbrake on one notch!! Could be the hand brake not been tight enough on that side....it rattles within the rear disc

[Chris-W]

As Nelly says, but my bet would be a rear top mount.

[raj]

thanks guys are they hard jobs to do and how can I test to see if it is those parts

[Nelly]

Rear top mount - lift the rear part of the roof + open the horseshoe section - in there on the drivers side you'll see a black plastic rectangle - pop this up to reveal the top mount, ten to the penny you'll see tiny shards of rubber.

Also whilst looking at it, bounce the rear of the car slightly to see the movement in it.

Prop center bearing - doubt it is this but, remove the heat shields and grab hold of the prop in the middle - shake to see if there's any up/down/side to side excess movement.

Subframe bush - by jacking the car slightly under the diff, you'll be able to see the rear beam move/slide up the ally center of the bush.

[raj]

thanks mate how much are top mounts and what's the best place to get them is ittrue that you can fit m3 ones

[Nelly]

Yep - get the E46 M3 rear top mounts iirc, their about £9 each from BMW

[raj]

any chance for a part number thanks alot

[Brianmoooore]

33 52 6 754 096. Best replaced in pairs.

[raj]

thanks alot guys will be done on tuesday

[Brianmoooore]

Do it the easy way by removing the damper complete with the top mount, and fitting the new top mount onto the damper before replacing them together.
Don't fully tighten the bottom damper bolt until the rear of the car is at normal ride height again sitting on its wheels.