Dear All,
I'm sure that others have posted on this subject, but here are my thoughts.


I set about removing the original rear springs and dampers on my XJR in order to replace them with German spec dampers and lowered springs.


Removal of the whole rear suspension assembly would have been easier with the transmission jack which I used during re-installation. It is well-worth borrowing or hiring this equipment, as it makes the job much easier than using a standard trolley jack with only two castor wheels and a small diameter pedestal onto which to balance the sub-frame.


I supported the car on axle stands under the standard jacking points. First step was to remove the road wheels. Supporting the whole weight of the sub-frame under the final drive unit, I disconnected the monostrut from the body and removed the brackets on both sides securing the A-frame. I also removed the brake calipers from the hubs and hung them from the bump-stops to keep the weight off the flexible brake hoses. The ABS sensors tend to seize in the hub carriers, so it is easier to leave them in place and to unplug the leads from the harness under the rear seat. I would also recommend unbolting the over axle exhaust hangers from the sub-frame, otherwise you will tend to pull the exhaust down with the sub-frame. Obviously it is also necessary to disconnect the propshaft and handbrake cable. The sub-frame can be lowered using the transmission jack mounted under the final drive unit. The lower damper bolts will need to removed to allow the springs to fully decompress. Once the road springs are fully decompressed, I would recommend lifting each wishbone by hand and wedging some 1cm / 0.5" thick blocks of wood between the A-frame and the underside of the wishbone. When you lower the whole assembly from underneath the car, it can be dropped to a lower height on the transmission jack without the bottom of the hub carriers dragging on the ground. With the springs decompressed, the spring pans can be unbolted from the underside of the floorpan. The springs and dampers can then be removed as an assembly. Newt I disconnected the monostrut from the wishbone tie. This will aid removal as the sub-frame assembly is withdrawn sideways from underneath the car.


Apologies, if I have missed out any steps in my description, but I am writing this description many weeks after carrying out this work.


I stripped the whole sub-frame off the final drive unit and sand-blasted it and repainted it. These pressed steel assemblies are likely to be very rusty after 20 years and are expensive to replace, so refurbishing them was my preferred option. I replaced most of the major fasteners during the refurbishment. However, I discovered a couple of mistakes in the www.jaguarclassicparts.com website. On the rear frame carrier illustration the fixing labelled 21 is actually SH112301M and requires 2off per side and fixing 22 is SH110201MJ and is only 1off per side. (The part numbers and quantities of fixings 21 and 22 are swapped). Also when I ordered SH112301M what I received had a fine metric thread and did not fit the standard metric thread pitch in the weld nuts in the unfloor plan, so I sent them back. If you choose to buy SH12301M check that the pitch is the same as the old screws that are being replace. If a fine pitch screw is screwed into a standard pitch weld nut the thread will be stripped, which will cause major problems. Many of the fixings used in this refurbishment are sold by Jaguar in packs of 10. This is expensive, when you only need two. I now have plenty of spares of BH112091J, BH112121PJ SH212201MJ and SH110201MJ, if anyone wants to contact me about obtaining smaller quantities.


The car is now back on the road and handling much better with its new springs and dampers. The pressed steel rear sub-frame has been refurbished and hopefully will last another 20 years.

 

Thanks Andy!

What lowering springs did you use, and did you fit lowered springs to the front?

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You can just bend the lower plate down to get the dampers/springs out of all 1995-2003 sedans and X100s. No need to lower any rear suspension units but many people do.



bob

 

I need 2 x BH212091MJ and 2 x SH212201MJ if you have them?

 

dfieldsen, please see my personal message to you.




I don't have BH212091MJ but I do have BH112091J, if you mis-typed the part number that you want. I also have SH212201MJ.

 

Al,
I am in the process of fitting a matching set of lowered springs to the front. They are second hand, so I don't know the supplier, if that is what you are asking. I may be able to find out more from the previous owner. They are claimed to by 25-30mm lower than standard. I haven't actually measured the difference yet in ride height to my other XJR6 which is still fitted with original standard springs. However, visually I would estimate that they have lowered the ride by about the claimed amount. I'll try to remember to post an update in the next few days on the change in ride height and any difference in spring rate.

 

I have now measured the change in rear ride height with the lowered springs fitted. The distance from the top of the wheel rim to the inboard edge of the wheel arch vertically above the highest point of the rim was 118mm with the standard springs fitted. With the lowered springs fitted, this distance is now 96mm, so 22mm lower.


I've bought a 20mm diameter aftermarket XK8 anti-roll bar. I've also bought some spherical bearing rod ends to build some drop links to attach the new anti-roll bar to the standard attachment points on the wishbones. I just need to machine a couple of parts to allow these new drop links to attach to the wishbones. This arrangement will remove all the compliance in the standard bushes, making the stiffer anti-roll bar more effective.

 

Thanks for the update Andy. Are you using the Powerhouse UK rear bar?

This relates to my questions posed about the value of the larger Powerhouse UK rear ARB:

https://www.jaguarforums.com/forum/x...ay-bar-151900/


Will be curious to see what parts you need to machine to attach the rose/ball joint drop links. I would think off the shelf rose/ball joint parts would suffice since as the stock drop link is just a female metalastic end at the bar end, with threaded stud on the wishbone end.

Very interested to hear and see your results.




Another old related thread for reference.

https://www.jaguarforums.com/forum/x...iiiiny-124192/



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I am using a part from Ultra Racing (part No. AR20-293). I have no previous experience of this company. The bar appears well made, but is finished in white, which wouldn't be my first choice. It was supplied with matching white brackets to replace the standard parts (MNA3501AA) and stiffer bushes to replace CBC4901. I need to machine a pair of bosses with perpendicular threaded holes, so that I can attached drop links with rod ends at each end. I have seen people rigidly bolt a rod end directly the wishbone, but this provides none of the articulation that is necessary in two different planes. My drop links with rods ends at each end will provide the necessary articulation.

 

Here's an interesting dual anti-roll (sway) bar project someone did on an XK8/R:

Sway Bar Modification


Any progress on your development and testing Andy?

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That is interesting. Done right you could make it dual rate. soft initial and then the second bar coming into play.

Wonder how much it was tail happy when done?

I still need to install mine.

 

Hi Al,
On 22nd Dec I received the final parts I had machined to join my spherical bearing drop links to the lower wishbones. Then Christmas happened. Just need to brave the snow and get into the garage and bolt it all together. Hopefully |I will post some photos in the next few days.

 

I've now created a new thread specifically about my uprated rear anti-roll bar kit

 

Here is that current thread to reference:

https://www.jaguarforums.com/forum/x...ll-bar-194478/

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