Jon,

It takes full shop air at 120 psi to move it very slowly with the tag down. I just took it off the stands/blocks and had to cycle the shop compressor to keep the pressure high or it wouldn't come off the stands.

If the bus is running, it takes high idle and all the air it can make to move it. The front end is at gross weight, 14,000 lbs. At Mobile, I had to dump the tag to get the front up.

100 lbs of air will not lift the front