The front passenger corner on my 06 Super V8 has started dropping visually after the car has been parked for about 30 minutes. It seemed to sort itself out when I restarted the car but eventually I got Vehicle Too Low and Air Suspension Fault warning lights.
The car has 101K miles and I believe all shocks are original.
Is it safe to assume that the front passenger shock/airbag assembly is leaking and I should replace both fronts. I figure since the failure always happens on the same corner of the car the location of the failure must be there. It doesn't seem to be a compressor issue. The only other possibility I can think of is the air fitting there and I will check that out.
I've seen the videos and replacing the shocks doesn't look too difficult but I just want to be sure I have the correct diagnosis before I buy new shocks.
Am I overlooking any possibilities?
Thanks in advance

 

most failures are the top of the shock. Spray a little soapy water to see if it bubbles.
The air bag also fails. The fitting starting to leak this much after 101,000 miles is a low failure rate.

 

My original front had a leak in the top seal, I could hear it leaking out. I also had a leak in the valve where the air line screws into the shock (this was my fault for not screwing it back in tight enough). Try spraying soapy water around both areas. There's also an O-ring in the voss connection where the airline screws into the valve, this can leak.

 

My 2006 SV8 has only 60.000 km but has developed a substantial air leak on the top seal of one front shock, typically when cold below 6°C.
Your diagnosis seems correct to me as the most probable cause, just check with soapy water (in my case I could feel the leak with my hand and hear the strong hiss when opening the hood).
I intend to replace the two front shocks before winter.

 

Thanks for the replies. I started the car to pump the airbag then shut it off and listened carefully for a leak but heard nothing. I think this is a pretty slow leak so it won't make any noise that can be heard.
I will try the soapy water test.

 

HI
I thought I had narrowed down a leak on my XJ8, but before ordering a rebuilt from RMT (highly recommended, by the way - $351) I wanted to be sure. I went to my local hardware store, and bought a small brass cap. A 1/8 inch brass cap from the plumbing section. I unscrewed the air fitting from the shock, screwed on the cap, to isolate the bad strut. It confirmed my suspicion, as the system stopped leaking, and I could order a new strut with confidence.

 

Can you share the threads on the cap? I need one for my trouble shooting.

 

HI
The threading is actually a standard plumbing thread - I don't have the specs. I had been lucky enough to have another male fitting that I could screw into the opening on the top of the shock to make sure it fit. The part was $3.50, and was a standard 1/8 inch brass plumbing line cap from Ace Hardware. If nothing else, you could pull your fitting off the Jag and take it to a hardware store to be safe.

 

Thanks for the tip. That is an inexpensive way to confirm a diagnosis. I'll give it a try.

 

Could you please specify: when you unscrewed the air fitting from the shock (ignition off?), did the car progressively land down due to the leak in the shock ?
And when you fitted the brass cap to the airline, what did you do exactly: ignite the car to restart pumping and observe that the compressor stopped when pressure was reestablished in the circuit without the faulty shock (car still down)?

 

don't know how you used a pipe fitting on the front tower as my 05 is a m10x1 metric

 

Update on my car, I got the rebuilt units from Rebuild Master Tech. I was planning to replace both fronts last night but looking at the fork at the bottom of one of the rebuilt shock assemblies, it appeared to have been bent in. I measured it and it was about .100" narrower than the bushing it fits over so no way it was going to fit in this condition.
The other one appeared fine so it went on the passenger side, which is where I figured had the leak was. I didn't do the leak down test that has been discussed here but with the car in the air, when I removed the air fitting for the passenger side, the pressure had already bled out. when I removed the fitting on the driver side, it was still under pressure so I was now confident the passenger shock was bad. I put everything back together with one new shock on the passenger side and all is well, for now.
I still want to replace the driver side but will have to contact RMT and sort that out. At this point, I am less than thrilled with them. They shipped 5 days later than what I confirmed with them when I ordered and now I have one shock that won't work without being straightened out. That was not what I paid for. I will contact them today to see how we can resolve this.

 

I think they are swamped. I need to call them also.
If the cradle is bent in a 0.1 inch I would square back up. I am too easy.
I think the two RMT air struts on my car are okay. Need to drive it more.

 

TRMT got back to me and said I could return the bent shock but it would only delay my repair. I already replaced the leaking shock so I could wait but decided to straighten out the one I have and install it. The bend was not severe enough to concern me that it may have lost some structural integrity after being bent and bent back so I went ahead and did it and installed it with no problem.
I'm not crazy about my experience with RMT but their prices are good and remanufacturing quality seems to be good despite this minor hiccup.
Tomorrow morning I'm off on a 1K mile roundtrip, the first real drive in the car for me. I'm really looking forward to it.