I finally brought my 2003 XJR with 60k miles on it to a muffler shop today to determine where a clunking noise is coming from. I determined (the mechanic couldn’t find it) that it was coming from the outer bearing housing (I think). If I push on the top of the tire sharply, I can hear a clunk that sounds like the thud I hear when I hit even minor bumps. It is predominantly on the left side. There is about 1/16” or a little less of total movement in and out at the top of the tire when I try to move it. The right side is tighter.

Any ideas? Should I be concerned? Could it be something totally different? I am sure it is not the exhaust. It is driving me crazy.

 

What you are describing sounds like free play at the differential output shaft bearings. A minor amount is permissable, and the suspension load as you drive down the road and traverse small bumps is not going to make the halfshaft move in and out of the differential enough to cause a noise.

The lower shock absorber bushings are actually a heim joint bearing assembly. You will not be able to identify freeplay in these joints while the shock is on the car, and you can only feel a little lost motion in the joint when you clamp it in a vice and pull on the shock tube. You wouldn't believe how much noise this small amount of freeplay causes. You may also not believe what a hassle it is to change the rear shocks to cure your problem, but "it is what it is".

That said, it is somewhat false economy to replace the lower bushings on a 60K mile shock. You can buy the bushings separately, but they are not cheap and the shock valving may not remain intact for another 60K. I can't hear your noise from here, but it's probably only coming from one rear corner, and that's probably the reason why.

 

You are correct, left side only. Why only one side?

 

'Cause that's the only side that is worn bad enough to make noise. It thumps over even the slightest rough surfaces, right?

 

Yes, you are right on the money. How many hours does it pay to change both shocks?

 

I charge 4.0 X $80 to do both rears. I would recommend factory shocks if you are going to fit replacements, or risk that you are not going to approve of a possible change in ride quality with aftermarket. Billstein application listings are not as specific as factory, and I personally do not like the lack of compliance that the stiffer KYB's introduce. My butt, and hands, give me the impression that Jags drive "jittery" on KYB.I can't give you specific input on alternate shocks for your year and model, however.

 

definitly go with factory as JTO said

 

2 comments here. First the diagnosis of the rear shock lower bushing is easy. With the car on the ground lay underneath and feel the lower shock bushing while someone pushes the rear of car up and down an inch or so. If you feel any play in the joint it is bad.

I don't get a lot of 200k mile XJs at the dealer but I do get a lot of 100k cars and have yet to see a truly bad shock, bad upper bushings and lower joints yes. The lower bushings(sphereical joint) can be replaced on the car without removing the shocks. Support the swingarm with a stand, unbolt lower mount and remove bolt, jack up the swingarm until clearance for the joint is available, use a balljoint press(the small cup on standard presses is just about perfect) to press the old joint out and the new one in. Also if you do decide to do complete shocks I'm with every other experienced tech on this board, factory is the only way to go.

 

R_T,

Thanks for that, I sized up a procedure that way but never tried it: there didn't look to me like there was enough room to work around the lower wishbone. One of my '97 VDP bushings has been talking to me for a long time now, so I'll try that one first.

It surprises me that bushings are being servicedat the Dealership level, my impression is that they were hard to source because so few people were replacing them separately.

 

I just had a power steering hose replaced on the car today and the mechanic said the play is more like 1/4" total in and out at the top, is that ok? He thought it was coming from the u-joints. Can I live with this, or should they be changed?

 

I think the last bad halfshaft universal joint I replaced was a 1984 XJ6, about a thousand cars ago give or take. U joints permitting that sort of axial play would be also be clunking on and off the throttle. They are very easy to identify if faulty when inspecting a car, so maybe you should have somebody else take a look. Did you try Real_Tech's suggestion for checking the rear lower shock bushings?

 

if its a 1/4" thats way too much, i would really look at the hub bearing in the hub carrier. My wifes went bad and had less play than that. When I pulled it apart I had to replace the hub too since it was scored. Andy we do replace lower bearings in the shocks for the rear. I wish they were avail for the fronts, but no....i tried to sell a set today on a Stype since I saved a guy 4k, Another shop said he needed rear upper and lower control arms and the upper rear ball joints were left loose when a body shop replaced the subframe...And he was all ready to do that repair, but wouldnt get the real items fixed he needed after I tightened the ball joints....oh well, sometimes I just dont understand. maybe just gunshy now....

 

remove the lower shock bolt, supporting the hub assembly. Reassembled but inserted an additional 1/8" steel washer on the mounting bolt *between* the shock lower bush and the lower wishbone. The effect of this is to put more pressure on the lower bush mount. A bodge...definitely...worked like a charm though as my lower bush was not that obviously worn...unbelieveable amount of noise from these little buggers when they wear even a little...and of course, in a Jag...you notice EVERY little noise!

 

Mr PJK,

I just read your bodge method. Really, I'd have to say it is utterly and completely...

brilliant.

Wouldn't rely on it as a permanent fix, but if nothing else it's a great way to isolate the shock mount as the source of the noise. Thanks for your contribution.

 

LOL JagTech...owning old British cars makes me always look for the unusual answer.

 

I had the same issue with my 2000 XJR. I was the wheel bearing and I let it go too long and had to replace the hub also. Fix it now, it will save you about 450 (parts and labor).