Old thread, however I thought I’d offer an update.
My compressor needed replacement as it was basically dead. The compressor was located on a tray, with angled sides, mounted on the driver side just ahead of the front axle - very near the electrical compartment. With the genset out it wasn’t too bad for access, however because the unit was attached by corroded Phillips head bolts, removal was a bit longer than the 1/2 hour Gerald managed.
No room to put anything like a screwdriver so I had to improvise with a Phillips end held by vice grips. Eventually three bolts were removed. Used a template for the 4 screw holes for the new Viair 450C (room for it and just ~ $200) because of the angled sides on the mounting plate, a bit tricky to get the bolts in and tightened, but did prevail.
I used a 40amp Viair relay ($5), 10g wire with a 40amp fuse and because it was near the electrical bay, pretty easy to find power and ground. Also, the unit has a remote air intake attachment so I ran the line up to the front cap and mounted the remote air intake above the headlight assembly - should be reasonably dry spot.
The compressor works well, takes maybe 30 seconds to refill, although I have to do some sleuthing as it runs about every 1.5 hours. I’m thinking, based on the lean that resulted before replacing compressor, there is a small leak on driver side front - either line to the bags or the bags themselves but that seems unlikely.
Jeff