I've read nearly all of the threads on Air Suspension in this forum and they have helped me immensely. I'm finally at a point where I could use another person's opinion to suggest how I should proceed. Here's the story: This 2005 XJR has no history of suspension problems, most likely has all original parts, and has just hit 101K miles. I drove downtown yesterday afternoon and, while sitting at a red light, there was a quick and loud hiss from under the hood. I heard it from inside the car with the stereo on and it sounded like it was behind the glove compartment and slightly forward. The front suspension made a VERY quick adjustment in height and the front dropped about half an inch. It did not drop below "normal", so I assumed that it was correcting something like a ride height that was too high (although I knew it should have been a slow adjustment and not one as dramatic as it was).

I drove another 15 blocks without incident and parked the car. No unexpected noises or behavior, so I went on my way. I returned to the car four hours later and the front end (only) was very low. I started the car and got the "front too low" message. It went away once the car has risen to normal height, so I put it in drive and proceeded home. The front dropped gradually as I drove at highway speeds... and the the "air suspension fault" message appeared. I limped home and parked the car in the garage.

Next morning: I started the car and it rose to normal height. The compressor ran for it's timed 120 seconds and then shut off. No warning messages. I left the car running, popped the hood open, and walked around to the passenger side to inspect the top of the shock. As I leaned on the fender, I could feel the car drop ever so slightly, then the compressor would come on and it would rise to the correct level and the compressor would cut out, at which point it would slowly drop again and repeat the process. I do not suspect the compressor because it had no trouble raising the car in the allotted time. I swapped the number 1 relay out and the problem was unchanged. Damn. The rear suspension never participated in this cruel episode, so I'm grateful for that.

I filled a small container with soapy water in order to check the air line connection at the top of the shocks. No bubbles. Damn, Damn. I checked both front shocks and had no real reason to suspect one over the other except the the direction of the pronounced hiss the evening before. I shut off the car and could see an very, very slight drop in the front end only and, when I listened at each of the four wheel arches, I heard a definite hiss from the right front suspension behind the wheel. The other three corners were silent. The sound was more pronounced when I listened at the side of the car, through the wheel, and quieter when I listened at the top of the shock with the hood open.

So, relay looks good, compressor adequately compresses, no bubbles at the fitting at the top of the front shocks, hiss from front, right suspension more than six inches below the hood line as the ride height slowly drops. Damn, Damn, Damn. I have no reason to suspect anything other than the air shock itself. Suggestions? Comments? Should the front shocks be replaced as a pair? Best price and vendor for these? Any do-it-yourself tutorials out there on replacing the front shocks? Any comments would be appreciated!

 

Hi Portfoliolio,

I don't know the best source for air spring/damper units, but I recently replaced the air suspension on a friend's XJ8 with the Arnott coil-over units and the Arnott instruction video will give you an idea of what is involved whether you're replacing with new air springs/dampers or coil-overs:



My understanding is that with the Arnott air spring/dampers you will lose the CATS functionality, which may or may not matter to you.

There are usually a few new and used OE Bilstein units for sale on eBay. There are also at least a couple of companies offering rebuilt OEM or new aftermarket units on eBay (e.g. Suncore and Danyx/DAP). I think I recall one of our members installing the Suncore units but I may be wrong. You might try using the Advanced Search function under the Tools tab to see if you can find any posts about Suncore.

If you install a used unit, you may be able to get away with replacing only the front right one as long as you get the proper Comfort or Sport type for your car, which are probably Sport since your car is an XJR. The type of units can be determined by the color of the dot near the tops of your original units - Green=Comfort, Red=Sport.

Cheers,

Don

 

Excellent video! Thank you so much. Now I just have to confirm that the shock is bad. I honestly don't see that it could be anything else. The hiss that I hear does not appear to be coming from any location that has a connection or fitter, so it must be leaking internally inside the shock itself.

 

I would look for a used Sport shock. This way only one is needed.
If you go Arnott new air or a coil over both really need to be changed.
Depending on price I might go for two new Bilstein's. Most likely a good OEM to hopefully match the left front.
I saw the Bilstein shocks once on eBay at less than 300.00 each NIB. But this was a UK listing. Shipping to the US would be high. Maybe now with the exchange rate shifted this is an option again.

 

jaguar wants 1500 for one shock arnott a pair 860.00 on Ebay.

 

Bilstein is now selling the shocks direct. The US price I have seen is 800-900 each. Still high.
I was searching for shocks a year ago and saw a pair on eBay for less than 600.00. NIB Bilsteins. Some company was dumping stock. Did not look into shipping from the UK. Found a low mileage set of four used Sport shocks here in Texas for a good price.
There is a Bilstein distributor here in Houston. They are usually 20-30% off list. Usually the big discounts are for stocked shocks. Special orders are not discounted.

 

What is the part # for the Bilstein OEM replacement type sport air shocks? The shocks on my 06 XJR seem fine but I may be in this same position one day. I'm leaning toward just replacing the failed shock with an OEM style replacement instead of going aftermarket. And, you couldn't pay me to go to a coil shock LOL.

Considering they last 10+ years and you only replace the single one that's failed, I'm a fan of doing an OEM type replacement.

 

Bill Stein calls them air spring modules.
Front 44-069483
Rear 44-069506

 

Awesome, do you happen to have the sport OEM Jaguar part #s too?

 

It's done. I read (with dread) about all of the Torx bolt problems that others have had. I had to hunt down the necessary Torx T60 socket, and it turned up at O'Reilly Auto Parts. I positioned the socket and ratchet as best as possible, but it would not budge. I did a bit more adjusting and moved a couple of things out of the way and then another tug... and it was free! Or was it rounding off the bolt. It had to be rounding off the bolt. Nope, the bolt was free. I swapped in the new right, front air shock and put everything back together. I hooked the battery back up and then lowered the car most of the way to the ground. I did not lower it all the way since I thought that was asking for trouble and knew that my jack would be stuck under there anyway. The system pressured up within 20 seconds and lifted the car off of the jack. Success.

Things look good.... except I now have a "park brake fault" message. The car sits idling nicely and flashes the "apply park brake" message. I tried to apply the brake, but got no sensation that it had engaged or disengaged. I took the car for a test drive to ensure that the suspension felt "tight", and it rode wonderfully (but the "park brake fault" message appeared). I drove home and turned off the car, then started it again. The same "apply park brake" message appeared and I would imagine that the park brake fault message will appear again if I drive it. It is most likely related to the fact that the battery was disconnected for over 24 hours, but I don't know where to begin to look to get rid of this particular gremlin. I may just start another thread if no one here has any ideas. Thanks again for everyone's help!

 

As you disconnected the battery, the apply park brake is not a fault, but an instruction to set it.
With foot on brake pedal, manually press the electric brake switch down to set it. Should clear the instruction.

 

I found the "EPB recalibration" instructions in another thread and that turned out to be exactly what I needed. I read the instructions and was sure that a) someone was most certainly having a joke at my expense, and b) candid camera would pop up any time filming be for being so gullible as to think that there was such a thing as a procedure to recalibrate the parking brake.

Sure enough:

Reset the EPB module: a. Switch off the ignition. b. Disconnect the battery for 30 seconds. For additional information, refer to XJ range Workshop Manual Section 414-01. c. Re-connect the battery. 2. Start the engine. 3. Firmly apply and release the footbrake five times. 4. Confirm that the message "NOT CALIBRATED" or "APPLY FOOT AND PARK BRAKE" is displayed on the instrument cluster message center. This indicates that the parking brake is in calibration mode. 5. Lightly press the footbrake pedal. 6. Apply the parking brake by using the EPB switch. 7. Release the parking brake. 8. Release the footbrake. 9. Confirm that the brake warning lamp is no longer illuminated on the instrument pack and that the "NOT CALIBRATED" message is no longer displayed in the message center. 10. Apply and release the EPB five times to ensure no error is present.

Next up: Lower control arm replacement and time to replace a weak aux coolant pump. Thanks again!

 

You can go through all that 'mumbo-jumbo'of "press brake 5 times etc". if you like, but that's a lot of rubbish if you ask me (I'm sure you wont) but if you just do as "dsetter" writes above, the warning will go out and you would be go to go. (Press foot brake and then press EPB. Done!)

Cheers