Strange noise from rear nearside wheel - What on earth?

R

rp61973

Member
Another mysterious problem for discussion. When running over potholes or speedhumps I get a very odd sound coming from the rear nearside wheel. It sounds just like a backfire (like a cap gun noise). It is loud enough to make folk in the street jump (or stare). I have checked the following:

Rear section of exhaust (checked for knocking against base unit)

Offside rear wheel - this does not back the same noise. I have tested this by running, in turn, the offside and nearside wheels over a speedhump. It only makes the noise when the rear nearside wheel engages with the speedhump.

The strange thing is when I vigorously rock the rear nearside of the car up and down there is no noise? Even getting the rear to spring up and down by putting my foot on the bumper and pushing down hard does not make any noise.

I can only think it is the shock playing up, but these are relatively new from S&G Walker and have doen 2K miles maximum.

Any ideas? Even when I put the car on a ramp there is no evidence of what it could be.

??? ??? ???
 
If you think it's the s/abs just remove it and then drive over the speedhump to see if the noise disappears. They come off easily enough and although as you say, you can't see any reason for it, removing it will prove the point one way or the other.
The only other thing that I can think of that could possibly make a noise like that is if the toplink mounts in the boot have cracked part of the way round and are flexing the two edges past each other. (That's the long shot! :) )
 
Harvey, many thanks. I will start by removing the shock absorber and go from there. It is an Armstrong unit, so will be disappointed if it is u/s after so little mileage.
 
You could well be on the right track with the shock absorbers. The rubber bushes for the top mount (under the rear seat) can generate a very noticeable noise if not plump against the base unit. It's also almost impossible to replicate by bouncing the car. It seems to be the rapidity of the motion rather than the amplitude that causes the noise. But audible from outside the car?... Mmmm.

Chris
 
It is very strange and very noticeable on a warm day with the window down. It is a sharp, almost explosive noise, just like a backfire (which I thought it was at first). I will remove the n/s rear shock and find something ramp-like to drive over.
 
are the shock nuts tight?if loose they could cause the knock..if u go down the route of taking the shock off dont drive fast otherwise that side will bounce a lot. also check the spring is case it has snapped near the end.
 
Well, I have tightened the top mount and the bottom mounts (not much needed) and the noise has stopped. Another nice and easy fix!

Many thanks to you all for the help/suggestions.
 
You must log in or register to reply here.
Back
Top