As is typical when one has the rear suspension clunk, it's that time where I've got to replace my rear shock top bushings and will be proactively be replacing my lower shock spherical bushings too as they look rough. My Jaguar mechanic is of the opinion that the shocks themselves are fine.

Of course that process involves removing the A subframe, so that's an opportunity to replace the subframe bushings, and they aren't terribly expensive (although not cheap, about $120 for the pair). But I don't want to spend the money and time to replace them if they aren't a wear item of any significance.

So are the subframe bushings a good idea to go ahead and replace as a refresh opportunity since the part is off after 16 years and 50k miles?

Interestingly as an aside, it appears that the X300 XJR uses the same bushing as the XJ8, MJA2595AB(no longer avail) or its replacement MJA2595AC

The normally aspirated X300 XJ6 uses part CCC6875

Is there a visual or physical check to see if the bushings obviously need replacement?

Should I put these on the list while I'm in there, or not worry about it?

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With the brackets undone, the A Frame usually takes some persuasion to release from the mounting spigot. Even if the bushings are OK, this can be sufficient to damage the rubber. It's a lot of work to repeat if the suspension is reassembled and the A Frame bushes need replacing soon afterwards. For the cost involved, I'd replace them.

Graham

 

I agree with Graham. If you are removing the A frame then I would do the bushes.

I would also not contemplate putting back shocks that have done 50K. Shocks wear out gradually. Just because they are not leaking and appear to have resistance doesn't mean they are good.

I treat shocks as a service item and replace based on mileage. I always replace all shocks when I buy a car as a matter of course. Many will disagree but that's my philosophy.

I will guarantee that if you replace the shocks with decent new ones then you will notice a significant improvement in ride and handling, and be rushing to replace the front ones also.

 

Replace them, I made the mistake of just doing the shocks and then a year later having to do the bushings anyway. This was the first time around several years ago. Last year when I had the shocks done I did everything together

 

I don't disagree with the thought of replacing the entire shock at this point, but cost is a factor. I was already considering the cost difference of all the parts (bushings, bumpers, spherical bearing, etc) versus just buying an entirely new shock. So I am certainly open to that approach.

My biggest concern is which shock is really right for the car.


If I replace the XJR rear shock with the OEM green (USA) Bilstein the cost is $275+ per shock.

MNA3540CC to VIN (802554)
MNA3540CD from VIN (802555)

The German (yellow) XJR rears which are supposed to tuned a bit more stiff (according to rumor) are something like another $60-70 more expensive each:

MNA3540EA From VIN (747141) To VIN (802554)
MNA3540EB From VIN (802555)


I prefer OEM parts, but the aftermarket Bilstein shocks for the X300 XJR are the Bilstein B6 Heavy Duty model 24-185806 and they only cost from approximately $135 to $150 each. That's a huge difference.

BILSTEIN B6 - HD Passenger Car


So here's what I wonder: Is there anything inherently "special" about OEM green or even yellow Bilstein shocks that the XJR was fitted such that the aftermarket B6 would be noticeably inferior?

For example, are the OEM units somehow specially "tuned" for the X300 chassis, weight, etc?

One might think the huge delta in cost could indicate a quality difference where the OEM units were indeed somehow superior, but I suspect that is more likely from their being OEM parts and probably a smaller production run.


Maybe an easier question is who has put the B6 Bilsteins on their X300 XJR and what are your thoughts as to how they compare with the OEM green or yellow dampers?


Thoughts?


BTW, there doesn't even appear to be a lot of info on what the green OEM Bilsteins are equivalent to in the consumer Bilstein product elsewhere on the Internet, although there has been some discussion in Porsche forums. Some posts seem to think the green OEM shocks are essentially equivalent to the B6 HD shocks, so ....

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I was actually doing the same research just a few hours ago.
From what I read, the Bilstein B4's are close to the OEM ride feel for regular XJ6's(Maybe?) and the B6's are for a sportier feel and standard ride height like the XJR. B8's are for cars with lowered springs.

Different Vendors list the B4's as Bilstein Touring and the B6's as Bilstein HD(Heavy Duty) so naturallly I'd think the B6's are OEM replacements for the XJR.

Not exactly sure on any of that though. Still doing my research to make sure $650 isn't spent on shocks that provide a softer ride than OEM. I would actually prefer a slightly stiffer ride for less body roll

 

I'm also in the market for some new rear shocks. Do you reckon these:
Bilstein Jaguar | Euro Car Parts UK
equate to B4 or B6 shocks ?

 

It's hard to tell from their website. They list a part number that doesn't provide any results during a Google search. Usually the best part numbers for Bilstein start with a W followed by numbers. Some website even listen two b6 rear shocks but looking up by part number one is a bit touring shock and the other is a b6 hd shock. I would personally call the website/vendor you're going to order from to make sure you're getting the right part.

 

I don't want to hijack the thread but I am a little confused.
I though you had to remove the subframe to get to the shocks and springs but this HowTo Thread:
https://www.jaguarforums.com/forum/x...ent-how-62143/ suggests you don't need to.
Which is correct ?

 

So I went ahead and ordered the new Bilstein B6 Heavy Duty (HD) shocks spec'd for the X300 XJR.

The part number for the rear B6 shocks is 24-185806 or the old number BE5-6725-M0

If you are in a hurry, I'd order now. Apparently Bilstein is retooling and for some of these lower volume shocks the stock on-hand is all that is available for 6-8 weeks until Bilstein gets back into production.

Tire Rack was out, and I got them from Allshocks. The east coast Bilstein warehouse only had 10 when I ordered my two. I don't know how many they had in their west coast warehouse.

Al

 

I just did this on my 97. I did not have to remove the rear A frames. Its a big job, but a good spring compressor, some time, and some grunt did the trick.

 

The rear A-frame does not have to completely removed, and spring compressors are not needed for the job.
The A-frame does need to be lowered though, by removal of the support brackets and the rear frame bolts. The brake caliper needs to be removed and there should be enough room to slide the shock/spring assembly out once the upper spring pan nuts are removed.
The biggest headache is usually the lower shock bolts, which will probably be seized to the shock bush eye - budget for replacement bolts if you have to cut or drill them but these are quite cheap. A few days soaking in Kroil or similar may help prior to the BFH making an appearance.....
The spring upper foam bushings may be toast, as well as the lower "pigtail" rubber seats - these are not that cheap but worth doing once everythings apart....

 

Yep, I have the upper spring bushing and lower pigtail rubber on order too. They aren't that expensive and it's good to get them while it is all apart.

I haven't decided if I plan to order the upper and lower hard plastic spring spacers/shims though. I suspect they don't really wear unless they break. They are actually kind of expensive.

Al

 

Hi people, I assume item 5 is the upper spring bushing and the Lower Pigtail is number 2 ?
Should I also assume the upper bolts will be toast after removal ?

 

Thats correct - although mine did not have the lower plastic shims present which seems to be optional to adjust ride height...?
One other tip I'm sure you know : six-sided hex sockets for the bolt removals - these are damn tight and a 12-sided socket may strip the heads, if you don't own a set then invest in one before you start (metric sizes).
The upper spring pan nuts can be a pain, and some may drag the studs out with them on removal - I replaced these with (M8) bolts/washers with a little blue loctite, I think I used about 15mm long bolts....
Good luck !

 

The following 'how to' to replace X300 XJ rear shocks also details how to drop the rear a-frame:

Tech

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