Thanks for your input, Brutal. I don't know if I described the behavior correctly. Over sharp bumps at higher speeds the front end shudders and transmits vibrations through the steering wheel. Sometimes it "jumps" around.

I've had other cars with failed shocks, although never a Jag, and it feels exactly the same. It really doesn't feel like wheels out of balance or something in the steering rack.

Again, the springs seem to be fine...no warning light, car hasn't dropped. That's obviously a common problem but not what I or the original poster experienced.

Someone in another thread described something similar stating that he replaced the air spring/shocks and the problem disappeared.

Still, would like confirmation, or a way to verify that the shocks are bad, since it's a lot more expensive to replace these combined modules than with the typical car.

 

You need to look for oil leakage from the holes at the bottom of the black accordian looking bellows. There is just a plain ole electronic hydraulic shock in there surrounded by the air spring just like any other car. But some leakage on normal shocks is okay to a degree. If you see oil at the bottom of one of the air springs. Its a bad leak and you should replace it. Here's another issue, i and most in the industry feel that shocks should be replaced in pairs on each axle if they have over 60k on them. That becomes very expensive on a airsprung car. So consider that before just replacing. Yes the shock still controls suspension behavior over bumps, the air spring suupports the weight. Its just much harder to see the shock and very hard to bounce a corner of the car to check the shocks jounce and rebound with the air springs. Also check the the big bushing in the front lower control arm(the curved one) is not broken and leaking. It will have black to dark purple colored oil staining on the bottom. These take a harmmering on bumos and absorb alot of suspension action and vibration which is why they too are hydro filled. Past that i personally would be looking at alignment settings too, just to see where theyre at. Understand i like to touch and feel to diag and thats hard on the web.

 

I recall the Service Manager saying that only Jaguar dealers have the device which is needed to lock and unlock the suspension on these vehicles. I had intended to pass along the post-mortem on my 200 mile trip this evening, with heightened front-end bobble awareness, which is all good news: no bobble-induced lane changing or front end unpleasantries whatsoever, but had to first respond to the preceding post. So I would say, ok brutal, you tell me how the Jaguar Dealer diagnoses this problem. I'm all ears.

 

I already did, read the tsb i posted thats how they will do it. There have already been many threads in the xj8 section on air spring including air gauge testers that i made and used. I remove either each corner air line and screw these in and air them to 100psi. And let them sit. You need to spray the connection and make sure that the connection and or fitting on the adapter are not leaking giving you a false positive. . On fast leakers it obviouse quickly. Now heres thekicker. Jags method does not isolate a single air spring and ive seen many change that are not bad. Reason being is that if 1 say front corner goes down it pulls down other corners making you think theyre bad too. With the gauges you get to see each 1 sring. The only issue with either diag method is that air spring do not all leak static. In otherwords i also lift and drop the car on the lift to cycle the air spring up and down. There are many springs that check fine sitting on the ground but as you raise and lower the vehicle the seals pass a spot that they leak at and many times i can hear them actually go pshhh or however you want to spell it. No need have special equipemnt to check for air spring leaks. You do need it if you need to check for compressor operation to see if it air the tank to the correct bar pressure and time. Someone could always make a fitting and guage to go inline on the reservouir tank line to check this though too. Then youre only left with calibration which there is no way around it but at the dealer with the tool and software to properly calibrate the air suspension system. But seldom does this have to be done.....

 

I'm going to pass on the "3rd opinion" thanks. The Service Manager from the Dealership has provided the most helpful information for those who need it.

 

The service manager did give you a little bad advice for sure-this can be diagnosed without being at the dealer. Euro-Tech in Edmond has all the info and tooling to perform any repair to your Jag. Give them a call you will be presently surprised.

 

WOW, nice. I work at a dealer and have for 14 yrs as a master Jag tech. you can certainly go spend your money there afterall its your money.I just pass along info here to help DIY'rs and others to make informed descisions. I can also tell you that HIS way results in alot of misdiagnosis and unneeded parts replacement...nice dis

 

screwby

 

 

Brutal, you stated:

"Then youre only left with calibration which there is no way around it but at the dealer with the tool and software to properly calibrate the air suspension system. But seldom does this have to be done....."

Can I change out the shocks with the Arnott's replacements and then decide to get it calibrated? Is it a must or is it on a case by case basis?

 

case by case. I maybe have to do 1 in 10 after spring replacement. The common trait seems to be more the people that continue to drive around on them down, and or ones that drop very quickly from a bad leak when not driving and the compressor airing them up. (this is bad cause its the number 1 thing that burns out/weakens compressors) this seems to make the suspension control module THINK that ride weight is okay or maybe it just defaults to not trying to bring the car up anymore.
the only time I calibrate is when afte rplreacment the car refuses to comeup even after being driven around the parking lot and started/stopped a few times.

 

Brutal, if instead of the Arnott replacements, I went with the Black Dog Manufacturing's coil over spring replacements, there wouldnt be anything to calibrate would there?

From what I have been reading in the forum the air suspension is something I can "expect" to be dealing with, so I thought why not nip it in the bud and deal with it today with a system that solves the problem.

 

I'm not so sure your logic holds up. My car has 65 K miles. I had to replace 1 air shock on the right front at 60 K miles. The right front is, by far, the busiest corner on the car. The other air shocks, so far, show no symptoms of trouble.

If my car is typical of others I would not rush into a conversion for 1 bad shock, particularly if you are cutting the cost with Arnotts. Additionally, if you follow the replacement procedures laid out earlier in this thread, you will not have to do a re cal. after replacement.

 

A little more information might have been helpful to understand where I was going with my thought process.

Before I purchased the car I had it checked out by an independent shop, he confirmed my suspicion about the front right, he noted a small leak in the front left as well. So I began backing myself into a new front suspension using the Arnott's replacements; the shop wanted $2,600 for OEM replacements. So now I am $800 into the front end, admittedly a good distance from the $2,600 for the Black Dog whole car replacements.

Now taking into consideration all of the forum commentary regarding the failure rate of the air suspension system, it just might be worth my while and piece of mind to get rid of the problem now and not throw good money after bad.

Would appreciate any further thoughts from any one who has dealt with the air suspension system.

 

every airshock has a valve on top. i changed those valves and solved my prob. is the airbag or airstrut or air supension...then that valve and then you connect the air hose fitting in to that valve. thats all..thank you

 

I hesitate to add much to this, as Brutal is very, VERY honest (Brutally ) and experienced, but for what it is worth...I have owned a 2006 XJ8 LWB, a 2004 XJ8, a 2009 XK, a 2011 XKR, and a 2017 F-type. And I do 100% of my own maintenance. I've converted two XJ8s to Arnott coil-overs, and it DOES make the car a wee bit stiff legged; do not expect the same ride quality. They add a level of brittleness you don't experience on the OEM air. They are good, I've done it twice, but my reasoning was to just lose weight/complexity (stripped 100% of compressor, tank, valves) and make the car more trouble free. But it does transmit a bit more road feel - some like it, some don't. And I will state that Arnott coil-overs are well engineered and pretty easy swap. Just do NOT expect the same ride quality, or you will be disappointed. Think Sport mode on some German cars - stiffer and less compliant. But then, after the conversion I can tell you the percentage of aggregate in the asphalt through the steering wheel.

Every.Single.Time. I have experienced a (the) symptom you are describing, it was a out of round wheel. Somewhere, sometime, somebody hit a pothole and darned if them there alloys don't bend. Before you spend a ton of hard earned $ - find the nearest Rim Straightening shop and get the to un-mount tire and check rims (usually the flat spot will be on inside, less support from spokes). Also, the 49mm backspacing on std XJ8 rims does not help, as the bend will be inboard and cause weird shimmy.

Good Luck to you, and I suggest in my humble opinion that the folks here are genuinely looking out for you and trying to help, they have no hidden agenda save sharing a wealth of experience. Which is probably not the case with the dealer.