Well, after nearly 3 years of hassle free driving, my jag gave me it's first real problem today.

I washed it and drove it this morning, and it seemed to me that the right front was sitting slightly lower than the left front. I thought I'd continue driving and see if it leveled out. After a couple of miles, I heard a couple of pops (kind of like mild backfires). I wasn't sure if it was my car or another nearby. After about another half mile, I heard / felt a loud bang. The bang seemed to me, to be coming from directly under the center of the car, but I was doing highway speed, so this might be misleading.

I pulled over and both front wheels are all the way up in the wheel wells. Both front shocks appear to be completely deflated. I could hear a screeching sort of sound. Not a hiss, more like the screech you get while letting air out of a balloon while stretching the neck. (horrible sound)

I drove it home carefully and parked it.

I just looked on the RMT website and I see that they are selling a pair of the Sport version front shocks for $565. Remanufactured SPORT Front Suspension Air Spring Bag Struts - Pair | Jaguar XJ-Series (X350/X358) 2004-2009

I also looked on the Arnott site, but theirs are $552 each (nearly twice the price).

My question:

Because of the bang, is there anything that I should be doing to diagnose any other possible issues, or I should I proceed directly to ordering and replacing both front shocks?



I knew this would happen eventually, but it doesn't make it any less annoying.

 

A couple of possibilities here, 1. a pipe has split, easy fixed, or 2. one or more shock bags has burst, expensive fix, but would be really bad luck if that was the case, the "screeching" is probably the compressor producing air to fill the burst shocks, and that air exiting through the burst rubber, because the suspension doesn't know they have burst, just thinks the system needs more air.
It would also be worth checking that the height sensors have not seized up or detached, before replacing any shocks, if the system things the suspension is low, I believe it will just keep adding air, which would over-inflate a bag and probably cause it to burst.

Hope it's just a pipe that has split.

 

The folks at RMT state, "The second factor of an air strut failure is the strut itself. The strut is pressurized with fluid, and if the strut begins to fail it will no longer have the same pressure to hold the vehicle. If this system begins to fail one visible sign will be that your vehicle will be lower than factory height." <---- This is patently false. The airbag holds the vehicle up, not the shock component. There is no fluid in the airbag. Any company promoting this type of understanding of how the module works doesn't have enough understanding of the basics to be making such a claim. Second, reman units use the old shock component, and Bilstein does not vend out that component for reman. You can purchase brand new Bilstein B4 replacement modules for just around $700 US. Bilstein, the manufacturer of the original air modules for Jaguar recommends comfort as the direct replacement for all X350~X358 vehicles including XJR, and Jaguar states you should never replace a module that is 7 months older than the date of manufacture. (because of limited life of air modules, and certainly you do not want NOS)

 

That's all bit misleading and confusing. A Bilstein air suspension strut is a combined air spring and damper. The damper is inside along the centre-line of the unit and is surrounded by the air bag.

True there isn't (or shouldn't be) any liquid in the air bag (the spring component of the device) but there certainly should be liquid inside the damper component inside the strut. So, if liquid is seen to be coming from an air suspension strut then it's a pretty good indicatìon that the damper component has failed, and the whole unit will have to be replaced.

 

Air is a fluid. So is silly putty. As are my thoughts.

Since the airbag and the strut are a combined unit, the distinction between them is not particularly relevant. But it's clearly a problematic weak point longevity-wise on this car.

Wouldn't a suddenly burst "Air Shock" cause just that corner to go down in the short term? since they are separated by the valve control block in the boot?

 

Edited fluid to liquid ... happy ?

 

It was in the original RMT text :-)

 

Weak point? 10~15 years of service from an air module is quite good actually. You have tires on your vehicle that are that old? Jaguar isn't the only automaker using air modules, as BMW and Benz also use them widely in their vehicle lines, and we are now seeing them used in the Big 3 as well as others. The real departure point, for me at least, is the owner who seeks to drive a vehicle that originally sold upwards of 100k, and does have some very expensive and unique technology built in, and want to purchase for next to nothing, and not spend the vehicle maintenance costs when trying to own one. Don't get me wrong here, I'm not saying trying to save money when you can is a bad idea, but if you cannot afford the cost of ownership, better to find a less expensive model to maintain.

 

I am merely following some forum discussions where (some) people are replacing "Air Shocks" with those coiled thingy's.

Anyway it's easy to distinguish an X350/X358 from it's predecessors. Just see if the owner keeps sticking their fingers under the wheel arches.
Finally, a cat that hisses...

 

Sudden catastrophic failure of the air spring diaphragm is normally accompanied by a loud bang. There is quite some pressure of air in that thing ! Some years ago on this forum somebody posted a photo and the resulting release of air had blown a big hole in the protective bellows that surrounds the unit. The bellows you see is just a cover, the real diaphragm is underneath and inside a steel "can". (actually this may be aluminium !). Replacement of the diaphragm 'should' be a routine replacement job, just like replacing steel coils on a McPherson strut, and Arnott used to do this and there are others still doing it.

https://airdominance.co.uk/

I suspect there is quite a lot of commonality of components with these Bilstein units. What is not clear is what work is done to the unit. For instance is the moulded top rubber seal re-sealed ?These are known to start to leak at some point in their life, not a huge leak but enough for the car to drop overnight. Then there is the damper part. I suspect these are not re-built, but being Bilstein, probably last a very long time, far longer than the air component. Clearly a unit that leaks oil has a problem and this is not fixed.That is my understanding.

 

If I were to ever go to coil-over, I would use Bilstein eCATS shocks for S-Type, and utilize 200/400 progressive coils, and retain at least the eCATS. Progressive springs will help with body roll to a point, but nothing performs as well as an air bag for progressive rates upon compression. It's one reason Jaguar stated what they did about the design and utilizing air modules.

When I made my buying decision on my last purchase of the X350, I included the cost of air module replacement in the total overall spend I was willing to pay for the vehicle. If you don't want to do that, buy a multi-year service contract that covers the suspension. (that will cost you more than the outright purchase of the modules though)

 

I do indeed have 3yr Mechanical Breakdown Insurance (I don't on my other cars) precisely because this car is complex and expensive. It appears to cover suspension provided "regular servicing" is done, professionally of course.

 

Sometimes the ol' adage hold true, the car you buy for the least will cost you the most.

The advantages of retaining eCATS;

Benefits of the enhanced CATS system include:

• Automatically optimized ride and handling under all conditions, maximizing comfort, handling and driver control
• Refined ride comfort for normal driving with softer damper setting
• Automatic recalibration of all four dampers to stiffer sports handling when road conditions demand
• Automatic change to stiffer sports handling when cornering, as with the original CATS system, but now with the inner wheels allowed to return to softer settings mid-bend, giving improved ride comfort and increased tractability from the rear wheels
• Automatic change to stiffer sports handling when braking. CATS also now allows the dampers to return to their soft setting earlier by continually monitoring the brake switch and instantaneous deceleration rate, unlike the original system, which remains stiff regardless of the deceleration rate during the remainder of the stop. This reduces harshness of road inputs during braking
• Automatic switching of the rear damper settings slightly ahead of the front pair at low speed to reduce transient understeer, giving improved agility and turn-in performance
• Automatic switching of the front damper settings ahead of the rear at high speed to increase transient understeer, giving improved stability

 

Sorry for being late in responding. No matter what I did, I couldn't get back into the forum yesterday. I just kept getting a "Bad Gateway" message. Anyway, the issue has gone away now. (The forum access that is, the car is still nose on the ground.)

Thanks to everyone for your thoughts and suggestions.

It seems as though I have a few things to look at before I order new shocks. I watched the Arnott video on how to change the shocks and it looks pretty straight forward. Just looks like I'll need a T60 torx bit.

 

Soak them with penetrating oil, over, & over, repeatedly as some are almost impossible to get out. Others come right out, without any issues, just like in Arnotts video. Good Luck to you

 

Thanks Wingrider.

 

Well, I ordered the RMT Sport front shocks. A couple of nights ago, I jacked the front of the car up and started on the project. The "how to" video that Arnott has on their website is good, but makes it look a little easier than it actually is. In any case, I got it done in about 3 ½ hours.

I did the left first and then started on the right. Once I got the right wheel off, here's what I found:


2004 XJR Front Right Air Spring Shock


Here they are on the workbench:


Both shocks on the bench.


The job wasn't too bad and I didn't need any penetrating oil. I'd say anyone with some basic mechanical skills could do this job and save themselves a ton of money. Once I'd finished, I started the car, and after the air compressor built up enough pressure the car rose to it's normal height. It has held air perfectly ever since. Problem solved... almost...

I have run into a problem that I'm hoping you fine folks will have some suggestions for:

After completing the job, I went for a test drive. The car handles just as it always has, but there is a really annoying rattle in the front end. It almost sounds like the bonnet is rattling up a down like it's not adjusted properly. That's not it, but I'm just giving an example. It's a really fast paced rattle and it's only heard on bumpy roads. On smooth highway, it disappears.

In doing the job, I disconnected the sway bar end link (to the control arm), the upper A-arm ball joint, and the air spring to control arm bolt. That's it... Those are the only three things that have to be disconnected down below. Under the hood, the four nuts that hold the air spring to the frame have to be removed of course. I replaced every nut and bolt and torqued them to the amounts listed in the Jag Chassis manual. I had no parts missing or left over. I'm fairly confident that I didn't leave any tools behind.

I guess I need to jack up the car again and make sure that there isn't a wrench sitting on top of the under shield or something stupid like that. But this rattle is driving me crazy and I can't fathom what it could be.

Any suggestions???

 

The photos show a typical catastrophic failure on one of the air spring diaphragms; there was a similar photo some years ago on this forum. The release of pressure is so great it has blown a hole in the protective bellows. The whole front drops down because the two air springs are controlled together using a single height detector, so if one goes down, the system lowers the other one to match, and should put up a "suspension too low" message as well.
Anyway, with one spring blown, it is only necessary to replace the blown spring, not the other. Of course it can be prudent to replace the other one, as it's the same age as the failed one, but if cash is not sufficient, one can only do the one spring if lack of means demand it.

 

Glad you had no issues with the lower shock bolt, they can cause major problems. Same good luck as you with my first set of front shocks, they came off with no issues, then replaced them with Arnotts, no issues so far. Your lower shock bushings probably need to be replaced.

 

Great job on replacing the front struts.

Two thoughts:

The ARB (sway) bar be problematic-bushes under a U bracket I think.

Perish the thought but it's not one of the new struts is it?