I have a 2000 Expedition with the air ride suspension, I noticed the rear suspension sagging on one side. The right side sits nearly 2 inches lower than the left. The compressor comes on as it should and lifts the truck but lifts it higher on the left, there doesn't seem to be any leaks, if the truck sits for a week the sag is still the same on the rear. Any ideas where to start on this one?

 

Replace the right rear bag. What's happening is the flex material has a leak which seals below a certain point.

 

I was hoping that it was a valve, the thing that confused me is that the difference in height from left to right remained the same whether the compressor had just shut off or after a week of sitting.

thanks