Sliding vane air compressor

I've got an ingersol rand SV120 sliding vane air compressor. It's supposedly oil-free. It's hydraulically driven from the PTO. The PTO is driving the pump just fine, but the air compressor would turn on, pump a little, sound like the air intake was folding in on itself, make a sucking sound, and stop pumping. I'd turn it off, it would run, then do the same thing. After a few times, it would run fine. Now it won't pump air at all. What's goes bad on a sliding vane air compressor that's oil free?

Air filter isn't even barely dirty, no sign of debris ingress. It sounded like something was pulling a vacuum when it would choke out, like if you suck on a milkshake straw too hard it will fold in. If you turned it back off the straw would pop back to shape. Now the straw is closed.

 

Once I get it fixed I'll be sure to run it regularly, being able to pick my own loads I don't hardly use the compressor for an offload maybe 2 or 3 times a month, the pump maybe once every couple months, but I keep the pump dry as a bone and well lubricated after a wash and before it gets closed up, and I'll run it for a minute or two once a week. I didn't think the compressor would ever jam up.

 

i know rightey tightey leftey loosey, is it hard to get that end cover off? The service manual was saying stuff about heating up a bearing with a torch to get the cylinder out...all i have handy is a socket set and some pliers.

 

The SV120/200 rebuild kit alone is $1200!! couldn't even find a price on the whole compressor, they don't even want to list the $$$ in the open.