problem with Quincy 335i rotary screw compressor

I am a technician with compressors and components sales and service. I am repairing a Quincy 335i rotary screw air compressor now and it just would not work. The compressor is going beyond the regulated pressure and blows the relief valve. I replaced the unloader solenoid, pressure control valve,serviced the inlet valve and blowdown valve and it still blows the relief valve. while servicing the inlet valve i noticed the shaft worn by approx. .005 thou of an inch the shaft is 3/4"(.750) when i checked it with the vernier it reads .746. Please help. Thanks Zaid Ali