Hi folks,
My 2003 XJ8 is bouncing hard in the rear going over bumps - kind of a "thunk". At first I thiught it was the spare wheel bouncing in the rear - but no. I've noiced that the driver side rear is sagging a bit - the gap between wheel arch and top of tire is lower that on passenger side.

Is this the shock or has the bushing deteriorated? My mechanic has suggested replacing the shocks but I'm not seeing any oil.

Could it be just the bushings.

TIA,
Tony

 

I had a similar issue on my 02 XJR. We isolated it to the right rear shock and just replaced the one at 70,000 km. It seems to be a bushing issue but the labor to get at it seemed to be reasonable to replace the shock. I bought the shock from Nally with the members 15% off.

Cheers

 

its the shock oils long gone washed away how many times does it bounce when you push down hard on the corner

 

Hi Tony,

road-dog's question is important: How many times the car bounces when you press down hard on the right rear bumper and let go? If the shock is still working well, the car shouldn't bounce more than about 1-1/2 times.


A common cause of loss of ride height is deterioration of the large foam "donut" spring isolator bushings, Part 5 in the diagram below. When I replaced these on our '93 the car gained 3/8" in ride height, but depending on how deteriorated the bushing is, the car could easily sag 1/2" or more:





On an X308 I am not sure what keeps the shock shaft spacer tube, Part 17, from banging around inside the center hole of the upper mounting plate, Part 6. On an XJ40 there is a rubber isolator bush that is supposed to cushion the shock shaft and prevent it from contacting the upper mounting plate, but when that bush deteriorates the shock shaft bangs against the mounting plate and makes a "thunk" noise that sounds like it's coming from the back seat when you go over bumps. It is possible that on your car the cylindrical shock shaft isolator bushes, Parts 13 and 14, have deteriorated and are allowing one of the metal washers to contact the upper mounting plate, which is causing the thunk you are hearing.

Let us know if your shock passes the bounce test. If so, they your bushings are probably shot, which is very common. You'll want to do both sides, since the bushes on the passenger side are probably not much better.

Hopefully an X308 suspension expert will chime in.

Cheers,

Don

 

Don B....has it on the button Tony ;o]
The big doughnut No.5 is often the culprit.
On an X308 it's quite rare for these cars to suffer from spring sag
unless they have done a lot of off tarmac driving.

When these big bushing No.5 does fail (usually at a high mileage)
it's best to replace in pairs....as is the shocks because you can gaurentee
if one has failed the other is close behind.
As Don has eluded...the number of bounces is important and the correct way to do it is to grab the rear fender at the wheel arch opening and bounce up and down a few times.....let it settle.
Follow this with a good push down and watch it as it settles.
Any more that 1.5 oscillations and you need to look at shock replacement.

Just because a Bilstein doesn't leak oil, doesn't mean it's serviceable as these
are a gas/oil design....and although others have tried different brands, it pays to stick with the OEM Bilstein shocks.
You have a choice of using the standard fitment 'Comfort' or you can go up tot he 'Sport' seting which firms up the back end a little.
I replaced my Comfort shocks with the Sport type in the back end of my Sovereign six years ago and firms up back end just a tad without being too harsh as befits a luxo car like this ;o]

 

Hi xjay8!

Great to hear from you! Been wondering if you were on a Himalayan trek or something! Welcome back!

Cheers,

Don

 

I had exactly the same issue ( bang in the trunk ), changed out the rear shocks with new Bilsteins and great running now

 

xjay8,

I should have asked, can you tell us this: on an X308, does the shock shaft spacer tube just fit tightly in the center hole of the upper mounting plate, or is there a bushing of some sort that prevents the spacer tube from banging around in the mounting plate? On an XJ40, there is a rubber "top hat" guide bush, Part 14 in the diagram below, that separates the shock shaft spacer tube, Part 12, from the hole in the mounting plate, Part 7:




Without that top hat guide bushing, what keeps the shock shaft spacer tube on an X308 from moving around in the center hole of the mounting plate? Is it just a close-tolerance fit?

Cheers,

Don

 

now have a good understanding of what,s wrong time to fix it 2 questions what shocks and what spring compressor ( these range from $25.00 to $1400 )

 

If yours is the standard sport model or comfort ride, here are the ones I have for sale https://www.jaguarforums.com/forum/p...shocks-103475/

 

G'day Don....thanks for the kind words ;o)
I've been around, just get tied up with other things and health issues....they always get in the road ;o)=)
But I'm still pluggin' with one foot in front of t'other.....onwards and upwards! ;o))

 

Don....if you look at your previous posting showing diagram 18... and at the top you will see the layout that must befollowe on reassembly.
It's designed in a way that the shock shaft is 'centred' by the shape of the big doughnut spacer and the way the 'cupped' metal washers and plastic spacers are assemnled.
The shock shaft is not a close fit through the hole....it's esigned this way to accomodate the flexing movement of the shock when the suspension contracts and expands.
This is why their are several 'el cheapo' shock offerings that have been found to not meet this requirement and snap the shaft or the bottom shock bush.
Hope this explains the mechanics of the shock mount....as it is quite a sophisticated design that must be installed properly.
This includes genertous use of copper anti-sieze on both sides of the big doughnut spacer before installing.
Understanding how this works....allowing a swivel action on the shock during suspension movement will prevent the dreaded sqwark/squeak and graunching sounds that will come from the rear end if not lubed and assembled correctly.
Last time I did mine was seven years ago and 70,000klm and nary a problem ;o))
The whole design layout is what makes a jaguar ride so sublimly quiet and positive.

 

Hi xjay8,

Sorry to hear you've been dealing with health issues. You can count on our prayers.

Blessings,

Don

 

Thankyou for your kind words my friend....we're seeing light at the end of the tunnel ;o]

 

No spring compressor needed for this job. Just lots of patience. Enjoy

 

Did anyone post a how-to with pics to do this job? I'm about ready to do it myself and would like photos.