Clunk, Clunk Every Trip
Discussion
This is devine retribution for having an easy job of the manifolds.
I am hearing a repeating clunking from the somewhere under the car? Noise is directly related to road speed and only heard at low speed (<30 mph) as road and engine noise will probably drown out clunk at anything higher. I have tried to identify problem as follows:
1. Free wheel down smooth incline with engine off. Regular clunk, clunk.. can be heard. Apply handbrake to slow car and clunking stops and re-appears when handbrake is released.
2. Driving car at low speeds you can hear clonking noise, gently accelerate and noise disappears.
3. Freewheel backwards and there is no noise? (is there no end to this mans talents?)
4. Jacked up each front corner in turn and rotated wheel - no signs of any problems or noises.
5. Had car up on ramp (courtesy of local Kwik Fit) and could find nothing out of place under the car.
6. Realised prop shaft has greasing points to the two U/J's, so spent Sunday moving exhaust out of the way so that I could grease them both. This made no diffrence so concluded that noise was not from propshaft.
It has ocurred to me writing this, that I have not yet checked basics - oil levels in gearbox and diff.
Howver, if thought process is correct, the problem could be
a) Rear wheel bearing
b) CV Joint within a drive shaft - but which one?
c) Differential
d) None of the above?
I would really appreciate any help and tips that would enable me to identify the possible problem. Plus any advice on the likely repair, source and cost of spares for instance.
This is really bugging me as we are enjoying TVR weather at the moment and I am now reluctant to drive the car.
I am hearing a repeating clunking from the somewhere under the car? Noise is directly related to road speed and only heard at low speed (<30 mph) as road and engine noise will probably drown out clunk at anything higher. I have tried to identify problem as follows:
1. Free wheel down smooth incline with engine off. Regular clunk, clunk.. can be heard. Apply handbrake to slow car and clunking stops and re-appears when handbrake is released.
2. Driving car at low speeds you can hear clonking noise, gently accelerate and noise disappears.
3. Freewheel backwards and there is no noise? (is there no end to this mans talents?)
4. Jacked up each front corner in turn and rotated wheel - no signs of any problems or noises.
5. Had car up on ramp (courtesy of local Kwik Fit) and could find nothing out of place under the car.
6. Realised prop shaft has greasing points to the two U/J's, so spent Sunday moving exhaust out of the way so that I could grease them both. This made no diffrence so concluded that noise was not from propshaft.
It has ocurred to me writing this, that I have not yet checked basics - oil levels in gearbox and diff.
Howver, if thought process is correct, the problem could be
a) Rear wheel bearing
b) CV Joint within a drive shaft - but which one?
c) Differential
d) None of the above?
I would really appreciate any help and tips that would enable me to identify the possible problem. Plus any advice on the likely repair, source and cost of spares for instance.
This is really bugging me as we are enjoying TVR weather at the moment and I am now reluctant to drive the car.
I know this will sound daft, but is the back "hub" nut loose on one side.. the mystery for me is that the noise goes away when the handbrake is applied, this means one of two things to me..
either.. the noise is directly related to the handbrake mechanism (unlikely unless the handbrake lever attached to the shoe/cyliner arrangement is touching the inside of the drum somewhere)
or.. the handbrake being applied is alligning something that was misaligned beforehand.. hence if the hub/drum was not quite sitting "square" (bad analogy) then the handbrake shoes would hold it where it should be.. this would also happen at higher speed by centrifugal force keeping it all in line hence the problem going away at a higher speed...
sorry if that doesn't make sense.. just 2 mins idle thought on the problem..
Cheers
Matt.
>> Edited by M@H on Monday 22 April 15:30
either.. the noise is directly related to the handbrake mechanism (unlikely unless the handbrake lever attached to the shoe/cyliner arrangement is touching the inside of the drum somewhere)
or.. the handbrake being applied is alligning something that was misaligned beforehand.. hence if the hub/drum was not quite sitting "square" (bad analogy) then the handbrake shoes would hold it where it should be.. this would also happen at higher speed by centrifugal force keeping it all in line hence the problem going away at a higher speed...
sorry if that doesn't make sense.. just 2 mins idle thought on the problem..
Cheers
Matt.
>> Edited by M@H on Monday 22 April 15:30
To M@H many thanks for your thoughts. Had hoped for more replies by now, but have new comments and would like your feedback.
I think that my own initial analysis was too complicated for most readers to comment upon and I had only served to distract from the obvious. Searching this sites database for for instance, for any previous references to transmission noise etc., very quickly leads one to believe the problem is with a CV joint on one of the drive shafts.
CV joint failure seems for some, to be a regular ocurrence, that can lead to a variety of strange noises and symptoms. Driving the car hard will accelerate failure, so that fits! Anyway, this is the route I am going to take unless somone out there can steer me differently?
I think that my own initial analysis was too complicated for most readers to comment upon and I had only served to distract from the obvious. Searching this sites database for for instance, for any previous references to transmission noise etc., very quickly leads one to believe the problem is with a CV joint on one of the drive shafts.
CV joint failure seems for some, to be a regular ocurrence, that can lead to a variety of strange noises and symptoms. Driving the car hard will accelerate failure, so that fits! Anyway, this is the route I am going to take unless somone out there can steer me differently?
Peter,
If you get under the car, put the handbrake up and the car in gear, you can twist with your hands each driveshaft and if there's any play it'll be the CV joint(s) replace in pairs, it's not worth just doing one as you'll only have to replace the other when the new joint weakens the old one on the same driveshaft.
The same test can be done for the propshaft - minus the exhaust
The diff cage bolts can work loose and as Steve Heaths S bible quotes "Can sound like an expensive fault" It's worth trying to tighten these up.
Cheers,
Dave.
If you get under the car, put the handbrake up and the car in gear, you can twist with your hands each driveshaft and if there's any play it'll be the CV joint(s) replace in pairs, it's not worth just doing one as you'll only have to replace the other when the new joint weakens the old one on the same driveshaft.
The same test can be done for the propshaft - minus the exhaust
The diff cage bolts can work loose and as Steve Heaths S bible quotes "Can sound like an expensive fault" It's worth trying to tighten these up.
Cheers,
Dave.
Message to Dave H & all
Did as you suggested. Backed car onto ramps, left car in gear and handbrake on. I then tested for movement of the drive shafts.
I could feel a couple of degrees of rational movement in the n/s shaft and slightly less movement in the o/s shaft. The movement in both cases seemed small?
Q1. Is this degree of movement likely to result in the noise I have heard?
Q2. When driveshaft CV's have failed, how much movement is typical?
Comments from all would be much appreciated.
Did as you suggested. Backed car onto ramps, left car in gear and handbrake on. I then tested for movement of the drive shafts.
I could feel a couple of degrees of rational movement in the n/s shaft and slightly less movement in the o/s shaft. The movement in both cases seemed small?
Q1. Is this degree of movement likely to result in the noise I have heard?
Q2. When driveshaft CV's have failed, how much movement is typical?
Comments from all would be much appreciated.
I am totally embarrassed, but duty bound to publish the eventual cure to the clunking problem.
Saturday - Put car on ramps, removed gaitors by cutting away the clips and sliding them out of the way and regreased the CV joints. This cure was suggested to me by a mechanic friend as sometimes the noises are simply due to lack of lubrication. No change, the clunking was as bad as ever.
Monday - Started to prep car for complete drive shaft removal. Jacked up O/S and lowered wheel back down onto layer of planks to increase ground clearance when working. Took wheel brace to nuts on N/S wheel as a prelude to its jacking up and removal - the bl**dy
wheel nuts were either loose or simply finger tight?
Anyway, removed wheel checked everything for signs of damage and all seemed OK. Put wheel back on, tightened nuts lowered car back down and finished tightening the nuts (my torque wrench is currently US). Went out to test drive the car - everything perfect
Anyway as a consequence of this episode I have now serviced all joints in the drive train, a good bit of preventative maintenance. But I am still embarrassed and feel a real pr*t
Saturday - Put car on ramps, removed gaitors by cutting away the clips and sliding them out of the way and regreased the CV joints. This cure was suggested to me by a mechanic friend as sometimes the noises are simply due to lack of lubrication. No change, the clunking was as bad as ever.
Monday - Started to prep car for complete drive shaft removal. Jacked up O/S and lowered wheel back down onto layer of planks to increase ground clearance when working. Took wheel brace to nuts on N/S wheel as a prelude to its jacking up and removal - the bl**dy
wheel nuts were either loose or simply finger tight? Anyway, removed wheel checked everything for signs of damage and all seemed OK. Put wheel back on, tightened nuts lowered car back down and finished tightening the nuts (my torque wrench is currently US). Went out to test drive the car - everything perfect
Anyway as a consequence of this episode I have now serviced all joints in the drive train, a good bit of preventative maintenance. But I am still embarrassed and feel a real pr*t
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