AND if after all this fails THEN U have to raise the regulator upping the air pressure a bit. Test and first watch it very close at see if the same thing is occouring as we found on Loydes bus. Get out a tape and measure thru pumping the brake causing repeated compressor cycles on high idle measure at the bottom of the first bay door at the back of the steer tire to the ground. U will begin to see just a very slight movement up and swoosh the dryer sneezes and it stops. Repeated cycles produce similar results till ride height is achieved. If U take it out of high idle often ride height will go more between cycles if not get there right off. Again if all else fails its the stinking air pressure and U could not ask for an easier fix.