The XJR had had a minor, intermittent clunk that sounded like it was coming from the left rear going over bumps. Tried a few times to find it, no joy. Wife tells me today it has gotten really bad. Sure enough it has. It is definitely the left rear. I confirmed it by running only the left rear over raised lane markers in a cul-de-sac.

With the wife bouncing the bumper, the clunk happens on the rebound and there is a visible pop vibration of the wheel and brake rotor.

Supported the left rear on a jack stand, bearing check ok. Removed wheel. Tire wear normal. Supporting the car using the lower control arm with a jack, bouncing on the bumper reproduces the cluck. Lower shock bushing looks ok.

Found that by supporting only some of the weight on the spring (spring compressed, but car still on jackstand) the pop occurs if I release the jack quickly. If I compress the spring and put my finger through the spring on upper shock body, I can feel the pop when I release the jack.

Further observation is if I slowly take the weight of the car on the control arm, the spring compresses along with the entire shock for about a 1/8-1/4" or so, after which the shock starts to compress. The upper spring perch does not move. Around the top of the spring is a brown-orange "dust" that looks a lot like the dust the front upper shock mounts give off when they go bad.

In summary, it looks to me like the top shock body is moving up and down when it shouldn't. If somebody has experience with this I'd like:

1. Confirmation I'm on the right track.
2. Pointer(s) to DIY replacement instructions.

Any help much appreciated.


-Mike

 

Looks like there is a way to do it w/o spring compressors: http://jaguar.blackonyx.net/tech/rearshocks.pdf

I seem to recall there was a method with compressors as well, and here it is: XJ8 REAR SHOCK REPLACEMENT Photo Gallery by Max Heazlewood at pbase.com

-Mike

 

The orange dust you describe could be from the bump stop. Could it be possible that it is allowing the top of the shock to hit the mount from being bad?

Not sure if that would cause it, but it's an idea?

 

Mike,

I think you're on the right track. The most likely cause of your knock is failure of the yellow foam rubber isolation bushes, Parts 13 & 14 if you have the conventional shocks, or Parts 21 & 22 if you have the adaptive suspension:




When those bushes fail over time (and they all do), they allow the shaft of the shock to bang around in the hole in the upper mounting plate, Part 6.

You will also want to replace the large foam rubber Spring Isolator Bushes, or "donuts," Part 5.

I would personally recommend that you not try to avoid the use of spring compressors - it will be far safer to use them. Many auto parts store will loan you a set through their tool lending program.

Cheers,

Don

 

Bringing this thread back. Finally was able to disassemble the driver's side. The upper shock isolator, #22 in your diagram, is nothing but dust. Once I got the lower shock bolt loose, the problem was very apparent, although I couldn't confirm until the assembly was out of the car.

I went the spring compressor route using one of these: Macpherson Interchangable Fork Strut Coil Spring Compressor Extractor Tool Set | eBay

Not a bad tool for $88. Very tight fit on the driver's side and one has to watch the fuel lines as the clearance with the compressor's top bolt is very tight. Had to assemble the tool on the spring. I think the passenger side will be easier.

Not a bad job until you get to the spring itself. Going back in looks to be a little tricky.

-Mike

 

It could be a loose shock nut on top. That was my problem with my vdp a few years ago.
Dave

 

I recently replaced the upper mounts on my XK8, looks identical. The spring isolator #5 should be replaced also. No noise now.

 

I'm pretty much following the procedure from post #2. That car was a XJ8 or VDP. For the XJR, it also helps to disconnect the sway bar to let the lower control arm drop more. Texas cars eventually need repaints, but no rust. So far, no frozen fasteners.

I took pictures as I went. The fuel line clearance to the top of the compressor is very small when first installing the compressor onto the spring. Withing a few turns of the tool, the clearance gets workable. Worst part was having to push the shock up into the spring. This put pressure on the plate and lower control arm making removing the spring difficult. W/o pressure, the shock expands slowly, so I let off the jack holding it and was able to pop the spring out before it expanded.

I marked the spring original location as well as where I clamped on the compressor for reinstallation. The lower spring perch is cut out for the end of the spring, so there is only one orientation anyway.

The last picture shows the top isolator is just gone. Lots of orange dust around the top of the assembly.

-Mike

 

I did my shocks on my old X300, same set up. I did not use compressors which was fine but had to disassemble a few things first (A-frame bolts, brake caliper/mount etc), it was not a pleasant job. One of the lower shock bolts was seized and I had to drill it out - quite common I believe but since the shocks were being replaced it didn't matter.
As has been suggested I replaced the large donut spring bushings, also the rubber spring "pigtail" seats as they were very tired.
Good job though, hope your lower shock bushings don't go any time soon as you will be repeating the process !

 

Got the right side out too. It looks a bit better than the left, but not much. Hoping to get parts and get this back together next weekend.

The right side was easier than the left due to more clearance.

-Mike

 

Now that it is done, I would agree it is not too bad, but it is not a pleasant job. The spring compressor I used was robust, but it was heavy, the compressor and spring assembly had to weight 40lbs or so.

As shown below, the upper isolators were shot. Also shown is the rear CATS shock. The upper metal half is just a cover. An impact worked well to remove the upper shock bolts. Do one at a time and us the amount of thread used on the other one to judge torque. This can be seen by looking down into the CATS electrical connector at the top of the shock.

Clamping the spring compressor to fewer coils gave more clearance for the left side fuel lines. Getting it in requires a fair bit of horsing around and an intermediate step of connecting the CATS plug. A bit detailed to describe, but the key is getting the spring clamped enough. It is also helpful to disconnect one end of the sway bar on an XJR. Zip ties are required to hold the top of the shock assembly to the spring while the shock is compressed.

I'm really glad its done. Rear suspension is now nice and tight.

-Mike

 

Hey Mike, great write-up and pictures! I have to do the same soon (if I can brave the cold). Just curious as to where you ordered your replacement parts through. Since you have the CATS system, as mine is, I want to make sure I'm getting the right stuff, and figured I'd check where you ordered through. Thanks!

 

For this job, the CATS parts are the same as the XJR parts are the same as the XJ8/VDP parts.

The upper spring isolator is P/N MMD3565AA ordered off Ebay for $36 each.
The upper shock isolator is P/N CAC949350 ordered from Motorcars LTD for $9.05 each plus shipping.
The lower shock isolator is P/N CAC949465 ordered from Motorcars LTD for $16.53 each plus shipping.
The bottom shock mount is P/N CCC6782, but I didn't replace mine as they didn't look bad and can be replaced on the car if need be. The shocks are original and new shocks come with new lower shock mounts, so I didn't think it was worth it.

JaguarClassicParts is very handy for part numbers: Find Jaguar Heritage Parts Online | Jaguar Heritage Parts UK

The spring compressor is noted above, and was about $88. All in it was about $220. 3 days to get it all apart, 2 days to reassemble. Could probably do it faster, but I didn't have to.

Now that I have done it, the non-compressor method may have been better, but there is lots more there to disassemble; however the spring/shock install looks less fussy. TX cars don't have a lot of rust, so I didn't have to deal with any of that.

-Mike

 

Awesome, thanks for the list. I'll be ordering up and doing the non-compressor version. My step brother has a bay open in his garage at his house, a heater, and air tools. I might drag someone along with a camera to get some video of it, and worst case, at least I can shoot a How-Not-To-Do-This clip!

 

Thank for the part #'s here for the bushings !