WRXrowdy

iTrader: (2)

There is a strange knocking noise coming from the rear of the car, sounds like a small log caught in the back wheel or the exhaust knocking, but a quick visual check shows no sign of anything loose, or anything caught in the wheel.

Any ideas what might cause this, could it be diff/prop shaft or drive shaft, or maybe wheel bearing or even rear parking brake shoes?

vulnax999

iTrader: (7)

Have you checked for small logs??

When does it occur ... driving straight ahead, over uneven ground, on a turn left or right?

Depending on year some impreza had problems with rear dampers.

Norman Dog

iTrader: (1)

It will be the rear shocks mate, starts off a small knocking noise that gets progressively worse until it has you pulling your hair out.

Gigsy

Check your Anti roll bar drop links... if it's not those, it could be the shocks as NG says.

What model year?

bunsofsteeeel

iTrader: (1)

i always thought it was the sti pink shocks that used to knock didn't know it was the wrx ones aswell.

Gigsy

The inverted design struts stick 05 onwards I believe... they can be regreased though.

s70rjw

iTrader: (2)

Jack your car up. apply white lithium grease to your bushes and spray up the shock absorber shaft to see if this quietens things down. As above, the struts can be regreased.

Read here, from Lancer register about regreasing them

http://www.lancerregister.com/showthread.php?t=312409

WRXrowdy

iTrader: (2)

Cheers for replys, car is an 03 blob WRX.
It is not a constant noise and can happen anywhere, even at very little speed on pretty smooth surfaces. I don't think that it is shock absorber related, although I could be wrong.
The car is now in the garage being looked at and so far they have come to the conclusion that I though was probably the case, that it is the parking brake shoes knocking inside the hub.
Will find out if this is the case tomorrow.

WRXrowdy

iTrader: (2)

Recieved the car back yesterday and it appears that the problem was none of the above.
Apparently the disc was to blame, where the pads are not in contact with the disc they have become rusty on the inside and fragments of rust have been coming off and knocking around on the metal crap plate behind the disc, although I think the noise was a little too loud for that and perhaps there was a stone in there that maybe fell out unnoticed, but the disc has been cleaned up and the noise has now stopped.

Thought I would update this incase anyone else encounters the same thing (sounds like exhaust falling off is best way to describe it).

vulnax999

iTrader: (7)

Nice one,

Glad you are sorted for now.

s70rjw

iTrader: (2)

Sounds like you have a garage who know their stuff. Good to hear its sorted

SRSport

I had something similar. I had knocking from the front nearside. It ended up being the caliper that was about to fall off as the bolt had come undone.
Just one of those rare things.