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Omega Help Area => Omega General Help => Topic started by: RobG on 27 March 2009, 19:32:45

Title: Noise from rear of car
Post by: RobG on 27 March 2009, 19:32:45
Posted about this before. Car passed MOT yesterday, asked examiner to doublecheck rear wheelbearings and driveshafts. No play whatsoever. When I first pull away get a knocking noise from the rear (similar to front droplink) for a few hundred metres then it disappears. When decelerating with no brake assistance get a rumbling/whining from the rear. When slowing with the brakes, sounds like a deeper rumbling/grinding. Would a rear bearing be worn and show no signs of play at the wheel? Could it be the drivegear in the rear diff? Could it be one of the driveshafts. As said there is no play either at the wheels or both ends of the driveshafts. Had the back up with the drive engaged and no noise heard. New rear discs and pads fitted last week, diff oil up to level, no visible leaks at driveshaft to diff. Has anybody got any other suggestions please :-/ :-/ :-/
Title: Re: Noise from rear of car
Post by: HI2DVY on 27 March 2009, 19:54:52
Have a good look at the rear springs. They have a tendency to break close to the ends of the coil and are sometimes not easy to spot without the car raised on stands. I had a similar problem on my meega last year and this was missed at the MOT  >:(
Title: Re: Noise from rear of car
Post by: vauxmad on 27 March 2009, 20:08:10
yeah prob the coils or could posibly be the diff but you would be able to hear that all the time
Title: Re: Noise from rear of car
Post by: RobG on 27 March 2009, 21:04:42
New rear springs 2k both OK and in one piece :-/
Title: Re: Noise from rear of car
Post by: feeutfo on 27 March 2009, 21:49:59
only noise i ever had from the back was donut bushes creaking... Diff bolts tight? When did the noise start? Was it after any work done.
Title: Re: Noise from rear of car
Post by: M0T0RVATE on 28 March 2009, 12:21:46
Quote
Posted about this before. Car passed MOT yesterday, asked examiner to doublecheck rear wheelbearings and driveshafts. No play whatsoever. When I first pull away get a knocking noise from the rear (similar to front droplink) for a few hundred metres then it disappears. When decelerating with no brake assistance get a rumbling/whining from the rear. When slowing with the brakes, sounds like a deeper rumbling/grinding. Would a rear bearing be worn and show no signs of play at the wheel? Could it be the drivegear in the rear diff? Could it be one of the driveshafts. As said there is no play either at the wheels or both ends of the driveshafts. Had the back up with the drive engaged and no noise heard. New rear discs and pads fitted last week, diff oil up to level, no visible leaks at driveshaft to diff. Has anybody got any other suggestions please :-/ :-/ :-/



I think a good way to find out is to get your car on a garage ramp, wheels up, and run it while mechanic gets under and listens for source of any noises...
Do you know the MOT guy well enough to ask him...??

Or ask if a local OOFer could come round and help out, jack car up safely on axle stands and see what can be found out...

 :)

Title: Re: Noise from rear of car
Post by: M0T0RVATE on 28 March 2009, 12:28:20
Ooops, sorry...you have had the back up already... :-/
Most of the obvious causes have been checked....

 :y
Title: Re: Noise from rear of car
Post by: Cameron on 28 March 2009, 12:36:12
Does the knocking increase in tempo with increased speed?

Had a problem when I first got the diesel that turned out to be the gearbox output shaft bearing.  Sourced a gearbox off ebay for £25.

It was a knocking that increased with speed, only really audible in 1st gear though.
Title: Re: Noise from rear of car
Post by: M0T0RVATE on 28 March 2009, 12:37:44
Driveshaft CV joints could be dry, loss of lubricant...
Bearing could be dry, for same reason...

 :question

Title: Re: Noise from rear of car
Post by: RobG on 28 March 2009, 15:38:36
Quote
Driveshaft CV joints could be dry, loss of lubricant...
Bearing could be dry, for same reason...

 :question

Silly question. If I remove driveshaft (pretty sure noise is on offside) what should I be looking for. Is it a case of removing the rubber boot and checking for grease or lack of :question
Title: Re: Noise from rear of car
Post by: M0T0RVATE on 28 March 2009, 17:31:22
Quote
Quote
Driveshaft CV joints could be dry, loss of lubricant...
Bearing could be dry, for same reason...

 :question

Silly question. If I remove driveshaft (pretty sure noise is on offside) what should I be looking for. Is it a case of removing the rubber boot and checking for grease or lack of :question


Yes, just check inside the rubber boot...it might not be an obvious leak, may have lost grease over many miles of driving...
Are you planning to take the driveshaft off then ??
Can you get enough access to check without removing shaft ??

This is an unusual problem, given all the checks you have made so far...

 :)

Title: Re: Noise from rear of car
Post by: RobG on 28 March 2009, 17:39:59
How are the CV boots held on, didn`t really notice when under the car :question
Title: Re: Noise from rear of car
Post by: M0T0RVATE on 29 March 2009, 10:49:45
Quote
How are the CV boots held on, didn`t really notice when under the car :question


Your original idea of taking driveshaft out is more practical...
Rubber boots held on with two clips, and outer joint has a metal cover that has to be knocked off...

Title: Re: Noise from rear of car
Post by: RobG on 30 March 2009, 16:34:43
Not had chance to whip off driveshaft yet. What I noticed this morning was when taking a sweeping right hand bend the noise got louder and increased in speed. Am I right it thinking that on a right hand bend the diff will turn the offside driveshaft faster and vice versa. If that`s the case would it deffo rule out the O/S rear bearing as the load is being transferred to the N/S :-/
Title: Re: Noise from rear of car
Post by: Cameron on 31 March 2009, 14:22:01
Quote
when taking a sweeping right hand bend the noise got louder and increased in speed. Am I right it thinking that on a right hand bend the diff will turn the offside driveshaft faster and vice versa. If that`s the case would it deffo rule out the O/S rear bearing as the load is being transferred to the N/S :-/

Yeah I'd say so, the outside wheel will turn slightly faster.

Does look like an NS bearing issue.