XAS 146 Atlas Air Compressor - Element Repair

I'm hoping someone could tell us what parts make up the air element in our compressor.

It had resently broken down, we dismantled the unit, rubbed back any visable damage so there were no high spots and bought 4 new bearings. We then found someone who claimed to know this equipment like the back of their hand, to fit the new bearings and set the rotor clearances when reasembling element.

He took 12weeks before he returned the element to us. He claims he spent 68hrs working on the element and bought parts which had cost him $500AU

Should it take that long? What parts? As we had already bought 4 new bearings.

Cheers Stacey