andyp

I've just noticed a sort of 'modulating'- droning' noise comming from the back of the car. Most obvious if I have the rear seats down and drive on a smooth road. I've heard conflicting explainations; either rear hub bearing or propshaft-diff bearing.

Is there any way to tell who is right without replace both!

Help,

Andy

Moss

I've become a bit of an expert on wheel bearings on Imprezas! I'm on my third relacement NSR bearing and the car's only just over two years old!

Your problem is infinitely more likely to be wheel bearing (hub) rather than prop or diff bearing. If you haven't done already get someone to sit in the back with the seats down and have a good old listen. In some (but not all) cases of wheel bearing wear the droning noise will change as the car is swung round left or right handers. Check by zig-zagging down a quiet stretch of road!

IM and my dealer have yet to sort my problem, and I've had a small bet with the dealer that bearing number three will go the same way as the others. I suspect that the hub itself is out of round, or oval and this is putting undue strain on the bearing when it is pressed in.

For your info... Original lasted 9 months, first replacement lasted 10 and the second one lasted 3 days short of two months!!

submannz

Most likely wheel bearings, the diffs are reasonably bullet proof, if you keep the oil levels right.

andyp

<<In some (but not all) cases of wheel bearing wear the droning noise will change as the car is swung round left or right handers. Check by zig-zagging down a quiet stretch of road!>>
Moss -- the noise doesn't seem to change if I corner, which why I guess one dealer said it was a faulty Propshaft bearing. Another dealer said that the hub could be bent, causing premature failure of the bearing - could be the problems your encountering?

Oil levels have always been good - despite one dozzy dealer only tightening the cover/bolt finger tight!

I'll keep you posted,

Andy

submannz

Are you sure it is not just tyre noise from the rear due to an incorrect wheel alignment, because that can make the same sort of noise you are talking about.

Or the other thing are you running different tyres front to read, maybe the charactoristics of that tyre is noisey on the smooth road surfaces.