Nearside Rear Mystery Clunk

JosephJ · 27th November 2023, 18:01

Hello everyone! My 75 has developed a dull, gentle clunk (like knocking on wood) from the nearside rear. The unusual thing is everything back there is new and all appears to be in good working order.

I've managed to get it up on the ramps at work but cannot see anything bad. All the bolts and nuts are tight, the exhaust has minimal movement and even with the anti roll bar removed the noise is still present. It's driving me mad! The noise doesn't improve with the brakes or handbrake engaged so I'm ruling that all out.

If anyone has any more ideas I'm more than happy to try them. The boot is also empty as well as the wheel and spare kit removed... I definitely checked that first!

Thank you,
Joe

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planenut · 28th November 2023, 15:36

Joe, perhaps you have found the source of the noise, if not, try to wiggle the exhaust system whilst beneath it, and recheck the fixings for the heat shields.
Good luck.

Mike Noc · 28th November 2023, 16:03

Joe when you get to the bottom of your clunk let me know - I've got something similar on the offside rear. Thought it might be anti-roll bar or droplinks but no change with it all disconnected.

Can't find any play so will disconnect the shock absorber and see if that is at fault. Failing that I'll probably remove the spring and then check all the suspension joints.

trikey · 28th November 2023, 17:36

Quote:

Originally Posted by Mike Noc

Joe when you get to the bottom of your clunk let me know - I've got something similar on the offside rear. Thought it might be anti-roll bar or droplinks but no change with it all disconnected.

Can't find any play so will disconnect the shock absorber and see if that is at fault. Failing that I'll probably remove the spring and then check all the suspension joints.

Same here too, I'm blaming the shock as well Mike.

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Mike Noc · 29th November 2023, 06:09

Quote:

Originally Posted by trikey

Same here too, I'm blaming the shock as well Mike.

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I'll whip mine off later today Andy. Not only can I hear the clonk I can feel it when going over minor bumps in the road which points to play somewhere - just need to find it. I've crowbarred everything in sight but so far nothing.

.

Dorchester2 · 29th November 2023, 06:36

I had a similar clonk sometime ago particularly on accelerations.
The mechanic found that it was my SS exhaust line that was the culprit (by the time rubbers become loose) and tapping somewhere. He added some washer and made the fittings tighter and bingo no longer any disturbing noise.

Mark Heappey · 29th November 2023, 07:02

I had a similar clunk on my tourer after a complete rear suspension overhaul with new everything. Turned out to be a top mount on the rear shock absorber that failed. Changed that and all good again. Nightmare job on tourer as interior has to be dismantled to get access to the two nuts holding the mount to the body.

Mike Noc · 30th November 2023, 07:25

Well I found mine - trailing arm front bush. Sadly found a fair bit of corrosion of the mounting too.
Couldn't feel any play but using a block of wood and a crowbar between it and the road levering the arm up replicated the clunk.

JosephJ · 29th November 2023, 06:06

Thank you everyone. Well, the exhaust is very tight (too tight?) But last night on the way home the noise got worse and worse to the extent my 75 is currently parked up.

The bottom bolt for the shock absorber, although tightened to the specific 155nm, has decided to completely strip the rear trailing arm that it bolts into. I could remove the bolt by hand! I'm unsure if this is the noise but I'll be replacing the whole trailing arm so will see if the noise goes away. If not, I'm thinking it's a faulty shock absorber.

I'll keep you all updated 👍

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JosephJ · 3rd December 2023, 15:23

Thank you again everyone.

Well, unfortunately I recently managed to strip the lower mount for the rear shock so a new arm was installed with a new bearing and ABS sensor. Guess what? The noise is still there!

I'll definitely check the exhaust centre mounts as the noise sounds almost the same. Also, my top mounts for the rear are new and tightened up well. I do have new front arms in place which definitely wasn't the most fun job.

I'll look at replacing the exhaust centre rubbers and see if that helps.

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27th November 2023, 18:01	#1
JosephJ Avid contributor Rover 75 Saloon Join Date: Jul 2021 Location: Basingstoke Posts: 104 Thanks: 0 Thanked 3 Times in 3 Posts	Nearside Rear Mystery Clunk Hello everyone! My 75 has developed a dull, gentle clunk (like knocking on wood) from the nearside rear. The unusual thing is everything back there is new and all appears to be in good working order. I've managed to get it up on the ramps at work but cannot see anything bad. All the bolts and nuts are tight, the exhaust has minimal movement and even with the anti roll bar removed the noise is still present. It's driving me mad! The noise doesn't improve with the brakes or handbrake engaged so I'm ruling that all out. If anyone has any more ideas I'm more than happy to try them. The boot is also empty as well as the wheel and spare kit removed... I definitely checked that first! Thank you, Joe Sent from my Pixel 6 Pro using Tapatalk

29th November 2023, 06:36	#6
Dorchester2 incurable Rover addict Rover 75 Saloon V6 2.5 1999 - Rover 25 1.4 2002 - Rover 214i cab 1994 - Rover P5b coupe 1968 Join Date: Sep 2017 Location: Bioule. South West of France. Posts: 1,645 Thanks: 612 Thanked 385 Times in 223 Posts	I had a similar clonk sometime ago particularly on accelerations. The mechanic found that it was my SS exhaust line that was the culprit (by the time rubbers become loose) and tapping somewhere. He added some washer and made the fittings tighter and bingo no longer any disturbing noise. __________________ Rover 75 V6 2.5 Auto Connie born 1 July 1999, 24 kOhms resistor, 10 kOhms manual starter, full E85, modified airbox, full derestricted SS exhaust line, power & torque remap -> 202 bhp This vehicle was the 7,517th 75 to run off the production line, out of 112,381 This vehicle was the 1,190th 75 2.5 V6 Contemporary to be made out of 8,214 This vehicle was the 2,032nd 75 in Atlantic Blue Pearlescent (code: JEY) to be made out of 2,572 Atlantic Blue Pearlescent 75s

28th November 2023, 15:36	#2
planenut Regional Secretary Rover 1.8T Tourer Join Date: May 2007 Location: Heathrow Posts: 6,976 Thanks: 1,551 Thanked 2,036 Times in 1,264 Posts	Joe, perhaps you have found the source of the noise, if not, try to wiggle the exhaust system whilst beneath it, and recheck the fixings for the heat shields. Good luck.

28th November 2023, 16:03	#3
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,569 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Joe when you get to the bottom of your clunk let me know - I've got something similar on the offside rear. Thought it might be anti-roll bar or droplinks but no change with it all disconnected. Can't find any play so will disconnect the shock absorber and see if that is at fault. Failing that I'll probably remove the spring and then check all the suspension joints.

29th November 2023, 07:02	#7
Mark Heappey Avid contributor Rover 75 CDTi Connoisseur SE Tourer Join Date: Aug 2010 Location: Pontefract Posts: 186 Thanks: 46 Thanked 36 Times in 23 Posts	I had a similar clunk on my tourer after a complete rear suspension overhaul with new everything. Turned out to be a top mount on the rear shock absorber that failed. Changed that and all good again. Nightmare job on tourer as interior has to be dismantled to get access to the two nuts holding the mount to the body.

30th November 2023, 07:25	#8
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,569 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Well I found mine - trailing arm front bush. Sadly found a fair bit of corrosion of the mounting too. Couldn't feel any play but using a block of wood and a crowbar between it and the road levering the arm up replicated the clunk.

29th November 2023, 06:06	#9
JosephJ Avid contributor Rover 75 Saloon Join Date: Jul 2021 Location: Basingstoke Posts: 104 Thanks: 0 Thanked 3 Times in 3 Posts	Thank you everyone. Well, the exhaust is very tight (too tight?) But last night on the way home the noise got worse and worse to the extent my 75 is currently parked up. The bottom bolt for the shock absorber, although tightened to the specific 155nm, has decided to completely strip the rear trailing arm that it bolts into. I could remove the bolt by hand! I'm unsure if this is the noise but I'll be replacing the whole trailing arm so will see if the noise goes away. If not, I'm thinking it's a faulty shock absorber. I'll keep you all updated 👍 Sent from my Pixel 6 Pro using Tapatalk

3rd December 2023, 15:23	#10
JosephJ Avid contributor Rover 75 Saloon Join Date: Jul 2021 Location: Basingstoke Posts: 104 Thanks: 0 Thanked 3 Times in 3 Posts	Thank you again everyone. Well, unfortunately I recently managed to strip the lower mount for the rear shock so a new arm was installed with a new bearing and ABS sensor. Guess what? The noise is still there! I'll definitely check the exhaust centre mounts as the noise sounds almost the same. Also, my top mounts for the rear are new and tightened up well. I do have new front arms in place which definitely wasn't the most fun job. I'll look at replacing the exhaust centre rubbers and see if that helps. Sent from my Pixel 6 Pro using Tapatalk