I've done this in my much younger and less wise days.
That compressor is still in operation with no repairs made to it.
are there tools used to check the piston and bore, or is this simply a visual inspection? if air cooled, how do i check the wrist pin?
close suction service valve, jump LPS till 0psig in crankcase, looking at crankcase and dis pressures, does the crankcse rise to dis pressure?
Is there an oil seperator?
If the compressor is only open dis, and the crankcase pressure rises and equalizes with dis, you have bad discharge valves.