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 This will aid removal as the sub-frame assembly is withdrawn sideways from underneath the car.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?

.

 

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/



.

 

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?

.

 

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/

.

 

Does a standard x300 (x305 in my case) have the mounting points for an xjr6 rear sway bar? I ask as there is an xjr6 in a fairly nearby wrecking yard and I'd like to pull the sway bar for my xj12. Assuming it will need penetrating oil etc to get off?

 

G'day Oliver,

I don't know the answer to your question but what I would do is take pix of the rear suspension of your car and when you when you go to the wrecking yard take everything that isn't in your pix.

Apart from the obvious bits such as the anti roll bar etc you'll need a different tie assembly as in the attached pic. The XJR bit has mounting points for the sway bar fittings.

Cheers and good luck,
Jeff.


[img alt="The two different tie assemblies.
"]https://cimg8.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/480x359/xjr_tie_265f8c3db46c79d6e2ea89efa2933428e119460d.j pg[/img]
The two different tie assemblies.

 

thanks!

 

Quick spool up to the area of interest is the difference between a torsion bar( A ) running all across and the different framing rear cross member ( B )

Pic coming from someone else's work , so you have a reference pic if applicable

This is a pic of the beefier X308 crossmember ( B ) that can be easily substituted and performs better on the X300

The X308 crossmember has different attach hardware at the top 2 car frame attach points ( X300 has free plain nuts on end of bolts and X308 has a bolt that threads into a nut clip ( this may or may not change the upper bolts shank / thread lenghts , so grab all hardware ))



So to remove crossmember in a junkyard situation

The long fulcrum bolt is a 17 ( could be way off as maybe 23 ) mm...................and with a spinning impact gun on front facing head I was able to migrate on its own just by spinning the long bolt fwd , will have to think more on its clearance issue and if any other stripping of weight like wheels or hub

In the case of the long fulcrum bolt coming out fwd interference , the trunk lower " tub " will only give you a inch of clearance between the 2 so impact gun extension and the hanging weight of the suspension components helps

wOULD HAVE TO LET LONG FOLCRUM BOLT SOAK A FEW DAYS IN ADVANCE AS HINTS THAT THEY ARE ALL DRY

You want to avoid pounding the bolt out and compressing / damaging rear threads so luckily on my example it migrated fwd on it's own , how do you aid or ensure this migration direction fwd ( ? ) once started you can pull fwd by holt head lip and lever

On large aircraft components we would use thread on bullets to go back in and may have to have one machined out least damaging threads and bushing lips on way back in but jiggling things may bring things back into alignment as it kind of floats around with main spring / shock still attached , turned out easy but may want to address the shock strut lower donut while there

Little bit of horn swaggering

 

Thanks for this, sounds as though it might be better to pull an x308 crossmember and sway bay instead of getting the xjr one? The soaking concerns me as the xjr I was contemplating harvesting from is 100 miles away at the other end of the bay area so not an easy roll...plus x308s are more plentiful in other yards

 

Don't know if the X308 crossmember was used on the X300 inline 6 XJR but would make sense , but hard to have a yard verify with eyes

Classic Parts may have the verification on paper but the production or other factors in reality...................

So we are looking at harvesting the crossmember ( B ) item and not the block with attach points straight aft of the Diff cover , block stays in place on crossmember swap

The crossmember is not a mirror image left and right side , you will see the difference and mark for installation

I'll be off and on rest of day