Rear end knocking sound

dale1uk · 9 Dec 2006 at 16:16

Hi I have a knocking sound coming, I believe, from the rear passanger side of my W reg 3dr Astra sxi. It only seems to happen at slowish speeds when going over bumps. First of all I thought it was the exhaust, but after removing the back box and having a drive the noise is still there. I then removed the rear wheel and jack, removed heat shields, and checked it wasn't the boot and the noise is still there. If I bounce the back end there doesn't seem to be any noise.
Now I'm starting to think it may be the rear bushes or the strut. Can anyone shed some light on this or throw any other ideas on what it could be?
I also believe it has cobra lowering springs on from the previous owner. The drops not big, 20-30mm, could these be causing or of caused the problem???

Many thanks.

Mr Joshua · 9 Dec 2006 at 16:32

I had something similar on my Astra and it was something to do with the brake compression cylinder, I told them when it went in for a service and they sorted it at no extra cost.

dale1uk · 9 Dec 2006 at 16:40

Hmm, seen that in the middle of the axle when I was underneath it this morning taking the exhaust off, but can't see how that would make the noise. Will have a look tomorrow though as all the normal things have been checked.

Many thanks.

Edit: I might be thinking of the wrong thing, are you on about the brake propotioning valve that controls the amount of braking force applied, in accordance to the weight in the back???

Mackass · 9 Dec 2006 at 17:41

Could be the rear bushes, mine are clunking like hell whenever I go over speed bumps or bumpy surfaces, and they need to be replaced.

dale1uk · 9 Dec 2006 at 17:53

Mackass said:
Could be the rear bushes, mine are clunking like hell whenever I go over speed bumps or bumpy surfaces, and they need to be replaced.

That's what i'm thinking, and from playing with everything else underneath and inside the back of the car, it looks like they could be the cause of the noise.

Mr Joshua · 11 Dec 2006 at 13:31

dale1uk said:
Edit: I might be thinking of the wrong thing, are you on about the brake propotioning valve that controls the amount of braking force applied, in accordance to the weight in the back???

I've no idea, I explained the problem at the dealership and that's what they said was wrong when I picked it up

.

utajoker · 11 Dec 2006 at 13:33

no one locked in the boot?

dale1uk · 11 Dec 2006 at 18:05

utajoker said:
no one locked in the boot?

Yeh but he's been dead for weeks