Hi

Some years ago there was a clonking noise from the rear of my car. I noticed a lot of people had similar noises and there where about as many ideas on the source of the noise as there were people and cars with noise.
Change of arms and bushings seemed to be the most common suggestions, but did not always solve the problem.

I changed some arms, links and bushings. That helped for a while and then the noise came back.

But now I found the true source of the noise, and the reason it appears is not strange, due to a poor design I would say.

The noise (in my car, and in most others I bet) is a result of the nut that attaches the ARB-link to the rear lower arm loosens just a tiny bit. And the sad thing is that there is no wonder the nut loosens. The ARB-link is fastened to a 1mm or so sheet metal part of the rear lower arm. In order for a bolt-nut joint to fasten properly the bolt need to be stretched to retain the forces in the joint when/if there is some movement, to keep the nut tight and not moving. 1mm thickness is far from enough length to stretch the bolt enough to retain the stretch in the joint. Eventually the nut will loosen just enough to loose the joint, and the noise from an ARB-link moving about in the fastening hole of the rear lower arm is a fact. Several people have reported in the forum that replacing the ARB-link solved the problem. Of course it did, the new one was fastened. After some time it will likely loosen again, like it did on mine. A fastening like this through a 1mm (or so) sheet metal hole in an environment like this is a poor design and an experienced engineer should now what will happen.

To solve the problem once and for all is simple. The stretch length of the bolt must be increased. Loosen the nut, put a distance of 10mm or so (a few washers or a larger nut for instance) and then re-fit the nut and tighten properly.

Note! The car should be standing on it's wheels when this is carried out, so back up a ramp or something.

What adds to that is the poor design with the allen-key at the center of the bolt, which easily breaks due to too less material, exactly what happened to me when I was to remove the nut. Drilled and threaded an M5, put a bolt inside and used to counter, works fine. I used again an allen-key type bolt, M5 is small enough so the M10 nut for the link passes over, stainless steel and glued it with epoxy so that it will hopefully work the next time I need to do something with the ARB link.

I hope this info will help all of those with this noise problem. Just to find out if this is it is really easy, just tighten the bolts of the ARB-link. Start with unscrewing a bit to make sure they are loose and then retighten. If the noise disappears, fit the distance-parts mentioned above to avoid the problem re-occuring.

After some severe noise lately, my car is not dead-quite, or at least the rear suspension is. No new spare or service parts fitted!

I am absolutely convinced jaguar is aware of the source of this noise, considering the amount of problems, the design "issue" and the source of the noise. Funny though it's not a well known thing, let's hope it will be now.

My car is an X-Type 2,5 executive, 2002. But I think this problem relates to more x-type models and years.

Happy DIY

Thomas

 

Hi thomasx, sounds like you may be on to sumthin here I'm guessing. Don't you think it'd be better in the relevant section for your car though? Its likely to get many more hits there I'd guess!
It'll be interesting to see what reaction you get from this......

Thanks for posting your findings

 

You failed to mention the model and year of your car, Thomas.

 

Please all, include model and year in a post title. It helps us all.

In this instance.. 2002 X Type Source of rear suspension knocking noise.

 

An excellent contribution Thomas, if I may say. 1st. class diagnostic approach. This partic. subject also interests me because at the left-side rear I get a peculiar "bobbling" rattle that almost disappears when wet or in hot weather (S-type). I also had a rattle in my XJ6 from the same area which turned out to be the bottom bearings of the shockers.
I've looked around the S-type and tightened many nuts/screws, along with shocker exam., but with load off the suspension, an error on my part I now see; the rattle has not altered. If anyone else has knowlege of the precise nut to address here, esp. with a picture, one would be ever so grateful.
Leedsman.

 

Yes, perhaps the X-type forum would be more apropriate. Was too new to have figured the site fully out when I wrote that. Tech help seemed like the place then

I guess it takes a moderator or admin to move the thread to the X-type forum?

Brgds

Thomas

 

Hi Leedsman

Thanx :-)

I remember having read in some forum that a rattling noise may come from the metal plate at the break pads. The ones that I think are there to prevent screaching noises, apparently can cause rattling noises instead Perhaps worth checking out. Do some search in the forum, there may be some info on that.

 

Hi Thomas, I didn't move it over because it looked good where it was.

However, might be better moved after all.

 

And thanx to you Thomas, I'll be checking that anti-squeal plate behind the brake pads p.d.q.
Leedsman.