Air compressor check valve. 3/8" Comp x 1/2" MPT with 1/8" FPT side port.  The check valve is a one-way valve that prevents air from back-feeding from the air tank. If your unit has a hard time restarting when trying to cycle or your pressure switch...

O-ring Seal for the discharge (outlet) tube to the pump head.

Old Part Numbers: 5130038-00, 5130024-001/4" OD brass compression nut and sleeve for bleeder (unloader) tube for air compressors.

Brass compression nut and sleeve for 3/8" OD tubes.

Screw (fastener) for the motor/pump shroud.

Isolator for the pump/motor assembly base. NOTE: To replace all of them you will need to order a quantity of 3. Keep your compressor from vibration damage and replace if any are missing.

Hex Nut for the pump head. The discharge tube attaches to this part. Order the required AC-0781 O-ring Seal as well if needed.

Universal Regulator: 4-port, two 1/4" FPT ports, and two 1/8" FPT ports (gauges sold separately here). The regulator controls the amount of air in your air compressor hose. Replace this if you're not able to adjust the PSI to your hose or if it leaks...