As I drive about I often get a creaking noise from the rear as I go over speed bumps or potholes not triggered by cornering unless there's a bump involved. I have done the lower shock mounts which were awful metal on metal screech.

I know there's a bush back there that needs attention but I don't want to just try things at random and I'm hoping against hope it isn't the top shock mounts as that's a big job on a daily drive.

Today I was jacking up the front end as it went up the ear end creaked. Can that be used to help identify the bush?

For what its worth on its annual MOT test the tester didn't detect any issues with bushes at the rear and I have had pry bars in and around bushes and sprayed them with silicon grease to see if I can shut it up and thus identify the bush. it has CAT shocks.

I suspect I need to get it on a ramp and have the local garage give it a really good going over but of course while very competent he only sees 2 or 3 XK8s a year for MOTs mainly.

Mike

Edit to accommodate stupidity: Of course I should have just jacked up the back to see what happened. Jack at jacking point creaks. Jack under axle' no creak.

My take is creaks on shock extending, no creak on compression.

It's going to be the top shock mount isn't it

 

It's always difficult for the driver to 'echo locate' a noise alone.
I think you need to get a second person to help out..
Whilst stationary, are you able to recreate the noise by pushing on the rear of the car? Perhaps someone could listen to identify which side it is coming from.

It might not be a shock mount. The rears are made of a different compound to the fronts and tend to last longer.

 

You are right I need some more ears on this.

I am somewhat encouraged as the ride height seems right at the rear.

I'd suspect those large A-frame bushes but I'm not sure how you test them.

 

Can the upper coil spring packer cause friction if it's dried out or something?

What's it made of?

My creak seems to be spring related as the spring vibrates 'in time' with the creak which I can trigger on demand using jacks.

It seems improbable that would be the cause. However spraying silicon grease up there seems to have reduced the creak which again seems improbable.

Hey ho got to cook tea.

 

The top of the rear spring has a Rubber 'Isolator' which is cleverly contained within a tapered cup pressing..
The bottom of the rear spring sits in a captive rubber 'pigtail' seat that perfectly fits into a profile in the cast Wishbone.
It means the rear spring is actually completely mounted and contained by Rubber alone and should never creak on compression.


Any degradation or damage of either upper or lower rubber element will lead to metal-on-metal contact and noise.
That said, the creak noise could easily be coming from a Damper.

 

Thank you.

I really don't want to take the spring etc. off but it looks like that is my future. I wish it was easy to rent a ramp in the UK, I'm pretty sure it would make the job a whole lot easier.

 

A splendid graphic.

Graham

 

Doc,
If you do eventually have to drop the spring(s), it's not too bad with just the rear supported on a pair of jack stands. It does mean a bit of scrabbling around on the garage floor, though...

Hardest part for me was getting the spring assembly out:- I removed the 2 bolts on the A-frame to allow the wishbones to drop a little further, but I still used spring compressors to avoid having to bend it beyond my comfort zone.

If you remove the lower bolt on the hub carrier you can swing it out of the way to give you better access. Just make sure you witness mark the bolt location as its head has an eccentric flange.

Nothing too difficult, just lots of dismantling to get there.

Good time to grease the UJs...

Good luck!

 

Thanks for the encouragement. I'm going to do some more investigating before I start stripping stuff down