Mystery suspension clunk

[Clifford Pope]

The rear left hand suspension, or something nearby, makes an intermittant clunk on rough surfaces, or on taking up or easing off the drive.
I've been round levering all the bushes - trailing arm, reaction rod, shock absorber, transverse rod, but everything seems solid.
I had hoped the recent MOT test would reveal the cause, but the tester could find nothing worn.

It's not constant - sometimes it goes for weeks in silence, then goes through a noisy phase again. It's impossible to predict which kind of bump/pothole is going to make it do it, and rocking or lifting the car when stationary doesn't provoke it.

I've tried removing tools etc from the locker, unhooked the back seat and support, checked with different petrol and LPG levels, but nothing makes any difference.
I've checked wheel bearings and handbrake shoes.
The fuel pump mountings are good.

Can anyone suggest anything else to investigate?

[Paul240480]

Hi

Are you positive that it is coming from that location? These things have a habit of 'sounding like its coming from there' only to be traced to another location, if that makes sense.

Being so intermmitent only makes it worse.

Gearbox mounts? - thinking taking up or easing off the power... engine mounts also?

Also, isn't their a bush of some sort in the drive shaft that can clonk?

Good luck.

[capt jack]

Exhaust?

Tailgate or rear wiper (if an estate) or boot lid (if a saloon)?

Handbrake cables?

Towbar (if fitted)?

Had this with a 240 Torslanda I used to own - turned out to be the back seat backrest. The noise would only happen intermittently and on the move, and didn't sound as though it came from ultimately where it actually did come from! The cure was to grease the catches. One of the problems with chasing noises is that they can be transmitted - and amplified - via the car's bodywork and end up appearing to come from somewhere different!

My present V70 can make an awful racket from the back end. The cure as I've found is simply to remove and replace the load cover roller blind. This stops the noise - until it starts again, maybe days or weeks later!

Hope some of this is a bit helpful - good luck!

Cheers

Jack

[Old_Car_Driver]

I think I read on here or somewhere that the rear brake pads can clunk or rattle if there is not enough copper grease on the back of them, they can move about noisily over bumps. Good luck solving it, there are few things more annoying than random clunks in a car

[Ashley Studdal]

Something inside the NSR door ? Something fallen off the regulator or speaker ????

[redboy]

I've found the best solution to random clunks and clonks is a louder stereo.

[honestjoe]

Hi clifford..mine is the same...and i"m sure i need new reaction rod bushes etc.but they still feel solid in situ...its that familiar clonk like things that go bump in the night and then its gone...i"m inclined to think its something suspension related..my bus does it as the car gets twisted while performing certain actions with the car..pulling away from left hand or right hand junctions..but as you say not all the time..stabilizer bar?...panhard rod?..i"m not sure if there could be any play sideway on the rear lower shock mount?..cheers hj.

[BrianH]

I tried everything.

After two years the only thing I had'nt changed was the Monroe air levellers as they were working OK.

Put on standard Volvo rear shockers............ Problem solved, rattle gone.

Still need levellers though, for the caravan, but can't find Monroe.

[Vallhund]

When looking for my clunk when i was underneath , i had the hand brake on and rocked the car . as the handbrake shoes have locked to the axle, whole lot rotate . I did,nt know the axle moved that far round. But you can see what dynamics are acting on the reaction rods very well as if under acceleration .

[Old_Car_Driver]

Originally Posted by Vallhund

When looking for my clunk when i was underneath , i had the hand brake on and rocked the car . as the handbrake shoes have locked to the axle, whole lot rotate . I did,nt know the axle moved that far round. But you can see what dynamics are acting on the reaction rods very well as if under acceleration .

Good tip, I will try that