Old Part Numbers: A19714, D27022Check Valve, 1/2" male NPT x 1/4" hose barb. If your compressor constantly leaks after it shuts off, this is probabably the problem. If this one-way check valve is clogged or defective, air will backfeed from your tank, so...

THD FORMING

Old Part Numbers: D20675, AC80-BQC .250 IND .25

1/4" male NPT x 1/8" female NPT brass bushing reducer for air compressors.

Old Part Numbers: A14877, N044990, SS-1286, 5130029-00, 5131153-001/4"-18 x 1" male NPT close pipe nipple. For model D55167 type 1 & 2 and others. Remember to apply plumber's tape to the threads.