I have two viair 480c compressors in my truck . they run for a very long time and it doesnt seem like there is enough air to lift my truck. should i replace my compressors?

maybe the bags that lift the car on the side that doesnt lift are punctured have you droven the car in bad roads or condition also thier could be an air leak in one the the hoses or pipes.

Viair makes the high quality portable 12 volt air compressors

no year,stated.
is this an HVAC question? and A/C compressor?
what air.? and what refrigerant? R12? or what?
on A/C systems, when breached , it needs to be pumped down
hard with a vacuum pump, as any moisture in the system renders it useless. or weak. and it will need oil of the compressor is new.
you seem to me , skipping all sacred steps, 1 by 1.... or?????
what got hot?. engine or compressor.
the rear will not lift, what rear of what, and lift what does that mean.??????????

have you read a book on basic, A/C yet?
or even the FSM on your car?

btw, on all modern cars, the Compressor clutch does cut out for
for up to 6 reasons. some are to protect the compressor from damage. (and icing of evap core, engine overheat, etc)

The better scanners can hook up to a connector port and diagnose the air lift system. This saves diagnostic time and the expense of replacing good parts. The trigger for your air ride system is probably one that you would not imagine. The trunk lid switches and the door jam switches tell the car that it needs to lower or pump up the system. The idea is that you want the car lower to load passengers and to lift things into and out of the trunk.

When these trigger signals reach the solenoids it is their job to add or release air. At least your pump is working. The diagnostic scanner will tell whether the solenoid is bad or a signal is missing to the solenoids. There is a master dump valve in front of the drivers wheel well to lower all ends at once.

If it is not lifting and the compressor is running, you have a leak in a hose, or a blown air spring, possibly an open solenoid-but try first to jack it up about 4 inches (shut off the compressor switch located in the trunk on the driver side fender)-you might have to drive the car up in some 2x4's to get extra height so you can get a jack under the car so it can be lifted-get it up so that it is off the tires, turn the compressor switch on again, and turn the key on again (or start the car)-see if it will raise now. If not, you need to look (or listen) for a blown bag or leaking hose. Do not run the compressor too much or you will replace it again-let it cool off in between attempts to locate the leak (soapy water in a spray bottle is your friend). the compressor is designed to 'time out' after about 90 seconds, so if it shuts off, let it rest, look around, and try again in 10 minutes after you have looked at the bags and lines (especially make sure they are pushed into the various locations. And, there are always spring conversions-once you do it, you never have to worry about the bags again. Air ride is nice but after 8 years, bags need replacing, and a system that is leaking ends up taking out other things like compressors, the hard to find relays, the dryer, solenoids at the bags, air ride modules, hoses...a decent spring conversion costs about $450, you can find used ones on ebay for as little as $200, and are not too hard to install with good tools and maybe a good helper.

Sounds like one/both air bag are leaking, check around the rear tires, if the compressor continues to run with a bad air bag it will burn up the compressor and drain the battery. your truck has a self leveling system

Sounds like the air gap on the compressor clutch is to wide, when the compressor turns off to recycle the electromagnet on the clutch is not strong enough to pull the air gap and lock up compressor. The air gap is adjustable and should be checked.

Hi

You probably have an air leak in the lines. Check for loose connectors at the compressor and at sensor (just follow the line) and for bent or broken spots. If, OK, check compressor pressure, it can also be that compressor is not pumping enough air to lift vehicle.

Good Luck!!

Could be low on freon

make sure the air lines are properly attached spray with soapy water to check for leaks