Help me diagnose massive clunk… video attached

[tommobot]

Any help would be massively appreciated!!

I'm at a loss on trying to track down this clunk on Saab 9-5.

Pretty confident its behind the drivers side (UK) wheel.

Subframe was dropped, and subframe bushes replaced with polybush through, ARB bushes replaced, droplinks replaced, shocks replaced and top mounts replaced (ORIGINAL SPRINGS RETAINED), front lower engine mount polybushed, new drivers (UK) engine mount - previous had snapped in half, new driveshaft on drivers side aswell.

The lower arms were replaced last year with new bushings, they look alright and I can't see much movement - The noise suggests massive movement somewhere though!

https://youtube.com/shorts/6zJwWo2JiOA

Clunk will not go way. Video attached of car driving over bump in drive vclearly audible. Help! I think the knock was there before all this work, its just made it much louder!

[durbster]

Not sure if this will help but just in case; when I had a similar problem, it turned out that an exhaust bracket was a bit loose and the clunk was the tailpipe knocking against the rear bumper. Took months to track it down.

[E-bmw]

Loose calliper or similar.

Either way it should be extremely easy to track down from under the car rather than just blindly replacing expensive stuff.

[GreenV8S]

Get under the car and push/pull on everything in the area. With such a heavy clunking noise from relatively small jolts it must be obvious what's moving.

I wouldn't take the car on public roads in that condition - it is potentially unsafe.

[tommobot]

E-bmw said:

Loose calliper or similar.

Either way it should be extremely easy to track down from under the car rather than just blindly replacing expensive stuff.

The subframe bushes were worn, and the cars got 160,000 miles on it so all the bushes were past there best..

Video probably doesn't show it but the clunk is coming from large indent in the ground..

You say easy to track down... Been trying to pinpoint bd knock for 2 weeks, shaken twisted, rocked everything, can't see anything obviously loose!

I'll have a look at caliper though..

[tommobot]

Right, it's definitely top mount related..

See video:

https://youtube.com/shorts/QgKugGf4_ys?si=QByGXb_5...

Shock assembly was tight when put together, so can only assume top mount which was newish is shagged. I do have a spare, I'll try that...

There shouldn't be isolation between top mount and underside of chassis.. even though I'm thinking top mount, can't really see how, or where the knock is..

[E-bmw]

tommobot said:

Shock assembly was tight when put together, so can only assume top mount which was newish is shagged. I do have a spare, I'll try that...

There shouldn't be isolation between top mount and underside of chassis.. even though I'm thinking top mount, can't really see how, or where the knock is..

Top tip.

Get someone else to video it when you are trying to display where it is coming from.

Another top tip.

Get someone else to apply pressure/torque while you feel for where the actual noise is coming from, it is much easier to pin-point where it is coming from.

[tommobot]

Completely agree, but people willing to help with my silly stuff are few and far between unfortunately..

[tommobot]

Took it for MOT this morning... Failed.. But not on the clunk of doom.



Tester couldn't find any movement anywhere, subframe or suspension related. - Rear brake hoses, leaky rear shock and cloudy headlamps...

We did hear play in the steering, when shaking the wheel on the ground.... However, he wasn't able to gauge where it was from even with him under the car at the time

I'll get the failed items sorted, and then he suggested taking to an MOT place with a hyrdaulic wheel shaker thing... and try and establsih where the noise is...

Obviously, no play in the rack through feel...

Rattles / clunks at low speed and about upto 40, beyond that stops and no distiguishable noise weirdly...

Edit: I put an OEM top mount on, that removed a bit of play that I found in the suspension noted previously , but clunk still massively there.

[lancer778544]

I've got a 9-5 too Tommo and the clunks it had were:

ARB droplinks loose on the strut (I've got Bilstein B8 shocks and lowering springs all round and the holes for the droplinks on the front are a bit oversized so I needed to crank the droplink nuts down)

Bottom ball joints - I had SKF ones on it that barely lasted a year, now running Meyle, only around £15 each and not that much of a faff to fit

Steering tie rod end

It too is fully polybushed and is currently noise free bar the gearbox input shaft bearing.

[tommobot]

lancer778544 said:

I've got a 9-5 too Tommo and the clunks it had were:

ARB droplinks loose on the strut (I've got Bilstein B8 shocks and lowering springs all round and the holes for the droplinks on the front are a bit oversized so I needed to crank the droplink nuts down)

Bottom ball joints - I had SKF ones on it that barely lasted a year, now running Meyle, only around £15 each and not that much of a faff to fit

Steering tie rod end

It too is fully polybushed and is currently noise free bar the gearbox input shaft bearing.

Yup, all changed / recently refreshed on mine... One of the ball joints were slightly different on the 1 side noted by Mr MOT manside that i'd fitted, but still provided zero movement when tested today..

I'm sort of convincing myself it must be the rack, or part of rack.. even though could'nt feel any play phyiscally...

[super7]

tommobot said:

lancer778544 said:

I've got a 9-5 too Tommo and the clunks it had were:

ARB droplinks loose on the strut (I've got Bilstein B8 shocks and lowering springs all round and the holes for the droplinks on the front are a bit oversized so I needed to crank the droplink nuts down)

Bottom ball joints - I had SKF ones on it that barely lasted a year, now running Meyle, only around £15 each and not that much of a faff to fit

Steering tie rod end

It too is fully polybushed and is currently noise free bar the gearbox input shaft bearing.

Yup, all changed / recently refreshed on mine... One of the ball joints were slightly different on the 1 side noted by Mr MOT manside that i'd fitted, but still provided zero movement when tested today..

I'm sort of convincing myself it must be the rack, or part of rack.. even though could'nt feel any play phyiscally...

Could it be the spring moving on it's mount? Or broken? But MOT would have picked that up.

[tommobot]

Exactly, told him the symptons... and we were both actively looking for the source of the knock but couldn't find anything...

Could 'hear' it when violently wiggling the wheel but he couldn't pin point it.. (Makes me feel a bit better, as I'm a bit crap at diagnosis sometimes) but actually flumoxed a 'pro' makes gives me a bit of confidence in that i'm not talking ste!

[bimsb6]

We had a mystery knock a few cars back, eventually traced by a garage with a “wobble” plate that shakes everything whilst on the ramp it turned out to be a drop link .