RE: Air gone HELP!!!
In a nOrMaL working system, it should be able to raise the front or rear up in less than 90 seconds. If it takes longer than this, the module(brain) will "time-out" and give up. Thus turning on the "check suspension" message and shutting down the system. After this has happened, the system won't try to make ANY adjustments until after the ignition is turned off, then back on. At this time, it'll try to raise the car again for another 90 seconds (or vent for 45 seconds).
Because "early in the stages of a leak", a leak will only leak while being driven, a leak will usually go on for at least 6-8 months before the driver even realizes theres a problem.....and to make matters worse, because the system is all automatic, as long as the compressor is able to keep up with the leak and meet the goal set forth by the module (brain) in the alloted 90 seconds, it may run 2-20 times more in a day than it would normally. This would be hard on any system, but even harder on an OLD system.....especially the compressor & relay.
It sounds to me like you started out with just a leak in the front struts. With time, I think it killed the compressor. It is also a very good chance you now have a leak in the rear air springs as well.
If you can ever get it up one last time, you should do a leak test to know where you are. You can try to help the compressor and "maybe" seal up the air bladders a little, if you use a floorjack and raise up the front just under normal ride height. This MAY help a weak compressor and/or leaking struts to raise the car up enough to do the leak test.
Remember this: To perform the switch off and drive leak test, you want the vehicle at the height its been at "most" of its life.....which is at curb height(lowered height=while unattended & hwy. speeds).
To do the switch off and drive leak test, go here:
http://www.americanairsuspension.com/MARK VIII LEAK TEST.htm
Good luck.