CLUNK Clunk clunk noise.. help
06-10-2023 | 07:06 PM
#17
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From: Oxford, England
Todd,
My effort with the half shafts suggest that one cannot really tell the condition of the CV joint whilst it is in situ but that may reflect the limits of my capabilities. On the other hand when you have the shaft in your hands it is very easy to feel whether there is any radial play. To get them out [if you feel such is warranted] you need a 3/4 inch socket set and a big lever arm- that or a very powerful impact gun.
Replacing the boots and cleaning out/changing the grease is a once in every "10 year job" as I am concerned and given your 928's background or what I understand of it such action would seem prudent no matter the actual cause of your perceived issue.
Rgds
Fred
My effort with the half shafts suggest that one cannot really tell the condition of the CV joint whilst it is in situ but that may reflect the limits of my capabilities. On the other hand when you have the shaft in your hands it is very easy to feel whether there is any radial play. To get them out [if you feel such is warranted] you need a 3/4 inch socket set and a big lever arm- that or a very powerful impact gun.
Replacing the boots and cleaning out/changing the grease is a once in every "10 year job" as I am concerned and given your 928's background or what I understand of it such action would seem prudent no matter the actual cause of your perceived issue.
Rgds
Fred
Todd.
06-10-2023 | 07:07 PM
#18
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From: Oxford, England
06-10-2023 | 07:09 PM
#19
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From: Oxford, England
hi Todd
noises and vibrations etc can be a real pain to find, i try to reproduce things like this when the vehicle is stationary, need a 4 post lift to keep the vehicle on all 4 wheels, then get someone else to bounce the body up and down while the vehicle is up on the lift and you are underneath, if you still cannot hear anything try holding components, shock absorbers etc to see if you can "feel" the noise with your hand.
could also try getting someone else to drive it on a private road while you sit in the tailgate area with the tailgate carpet removed to see if you can pinpoint the noise.
if it does it at slow speeds open the tailgate while its being driven, the more you can pinpoint its location, the number of things it could be decreases.
good luck
Phil
noises and vibrations etc can be a real pain to find, i try to reproduce things like this when the vehicle is stationary, need a 4 post lift to keep the vehicle on all 4 wheels, then get someone else to bounce the body up and down while the vehicle is up on the lift and you are underneath, if you still cannot hear anything try holding components, shock absorbers etc to see if you can "feel" the noise with your hand.
could also try getting someone else to drive it on a private road while you sit in the tailgate area with the tailgate carpet removed to see if you can pinpoint the noise.
if it does it at slow speeds open the tailgate while its being driven, the more you can pinpoint its location, the number of things it could be decreases.
good luck
Phil
I have the car up on ramps and have been bouncing / pulling it around, no noises. That makes me think its something in the unsprung mass area (ie, wheels, hubs, etc) rather than on the vehicle itself. I need to get in the back while someone drives...
Thanks!
06-10-2023 | 07:10 PM
#20
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From: Oxford, England
Speed-dependent knocking like that that goes away with the brake pedal sounds to me like a bad CV joint that's knocking when loaded in one direction and then the joint gets loaded in the opposite direction (and stops knocking) under braking. Or a bad wheel bearing (? Though that should vary with turning left or tight/varying axial load..). Are the CV boots intact? And the CV joint bolts are all tight to at least 60 ft-lbs to the transmission output shafts?
CV boots all look good. But your logic sounds good to me regarding the CV joints. Bearings all seem ok. Will keep searching but its getting closer to me pulling the half shafts off...
Thanks!
06-10-2023 | 07:11 PM
#21
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From: Oman
What size/profile are the rear 15 inch tyres?
Not to worry- assuming they stuck to the plus one sizing concept even in those days you probably have 215x60x15 rubber to give a rolling diameter of 25 inches thus a circumference of 6.5 feet. At 30 mph or 44 ft/sec that means the wheels would be rotating at 6.7 revs per second. Using my somewhat dilapidated flute playing skills I can resolve in my head up to 8 beats per second very accurately and up to 16 beats per second pretty roughly.
Listening carefully to your video tape a few times I reckon the vibration beats are coming at something less than 8 beats per second.
That suggests to me that in all probability what you are hearing is half shaft speed related.
Not to worry- assuming they stuck to the plus one sizing concept even in those days you probably have 215x60x15 rubber to give a rolling diameter of 25 inches thus a circumference of 6.5 feet. At 30 mph or 44 ft/sec that means the wheels would be rotating at 6.7 revs per second. Using my somewhat dilapidated flute playing skills I can resolve in my head up to 8 beats per second very accurately and up to 16 beats per second pretty roughly.
Listening carefully to your video tape a few times I reckon the vibration beats are coming at something less than 8 beats per second.
That suggests to me that in all probability what you are hearing is half shaft speed related.
Last edited by FredR; 06-10-2023 at 07:49 PM.
06-10-2023 | 07:50 PM
#22
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From: Riyadh, KSA
I think getting a set of chassis ears is a good investment in tracing noises.
Could be worn shocks, loose exhaust system (check that you have all your rubber hangers are there). Half shafts is an easy diagnostics (just have someone look at the shafts as you engage from P to D to see a movement mated with a clunk - should be zero.. any rotation and sound is a quick telltale).
Could be worn shocks, loose exhaust system (check that you have all your rubber hangers are there). Half shafts is an easy diagnostics (just have someone look at the shafts as you engage from P to D to see a movement mated with a clunk - should be zero.. any rotation and sound is a quick telltale).
06-10-2023 | 08:50 PM
#23
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From: Oxford, England
I think getting a set of chassis ears is a good investment in tracing noises.
Could be worn shocks, loose exhaust system (check that you have all your rubber hangers are there). Half shafts is an easy diagnostics (just have someone look at the shafts as you engage from P to D to see a movement mated with a clunk - should be zero.. any rotation and sound is a quick telltale).
Could be worn shocks, loose exhaust system (check that you have all your rubber hangers are there). Half shafts is an easy diagnostics (just have someone look at the shafts as you engage from P to D to see a movement mated with a clunk - should be zero.. any rotation and sound is a quick telltale).
06-10-2023 | 10:26 PM
#25
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From: Chicago Bears
I have been trying to solve the same problem for over a year, and finally solved it 2 days ago. Thunk thunk over big bumps.
Long story short - the driver-side exhaust pipe was hitting the cutout in the crossmember.
And I discovered it by wiggling the tailpipe side-to-side versus up-and-down like I had been doing.
Now that I have it diagnosed, not sure yet how to fix it.
Long story short - the driver-side exhaust pipe was hitting the cutout in the crossmember.
And I discovered it by wiggling the tailpipe side-to-side versus up-and-down like I had been doing.
Now that I have it diagnosed, not sure yet how to fix it.
Last edited by SwayBar; 06-10-2023 at 10:27 PM.
06-11-2023 | 04:59 AM
#26
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From: Oxford, England
I have been trying to solve the same problem for over a year, and finally solved it 2 days ago. Thunk thunk over big bumps.
Long story short - the driver-side exhaust pipe was hitting the cutout in the crossmember.
And I discovered it by wiggling the tailpipe side-to-side versus up-and-down like I had been doing.
Now that I have it diagnosed, not sure yet how to fix it.
Long story short - the driver-side exhaust pipe was hitting the cutout in the crossmember.
And I discovered it by wiggling the tailpipe side-to-side versus up-and-down like I had been doing.
Now that I have it diagnosed, not sure yet how to fix it.
06-11-2023 | 05:32 AM
#28
Burning Brakes
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From: Wine Country, CA
Turned out to be a bad rear wheel bearing. Took driving by a mechanic standing outside of the car to pinpoint the problem.
Last edited by jheis; 06-11-2023 at 05:33 AM.
06-11-2023 | 07:52 AM
#29
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From: Oxford, England
Update:
So it wasnt the heat shield.
But on my driveway, put in D and let it creep forward... tapping brake pedal and I hear the clunk, tap brake on/off/on/off etc and I hear clunk cluck clunk. Its defintely directly related to the driver-side rear hub.
Could it be the floating calliper clunking around? apply pressure and it all tightens up? Could it still be the CV Joint?
Out on the road it is never a single clunk, its always CLUNK Clunk clunk (each quieter that the first, like something vibrating/shaking a few times but less each time)
Does that help narrow it down?
Todd.
So it wasnt the heat shield.
But on my driveway, put in D and let it creep forward... tapping brake pedal and I hear the clunk, tap brake on/off/on/off etc and I hear clunk cluck clunk. Its defintely directly related to the driver-side rear hub.
Could it be the floating calliper clunking around? apply pressure and it all tightens up? Could it still be the CV Joint?
Out on the road it is never a single clunk, its always CLUNK Clunk clunk (each quieter that the first, like something vibrating/shaking a few times but less each time)
Does that help narrow it down?
Todd.
06-11-2023 | 08:09 AM
#30
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From: Oman
For purposes of clarity- are you saying you hear three clunks and the noise decays and is gone or is it more a continuous clunk that is somewhat cyclic noise wise [as best I could understand from listening to the video clip]?