Thanks!! So I'm guessing it needs a filter of some sort. I'll keep searching for a parts source. Seems to look an awful lot like the Kobalt LLA1683066.
Did you ever find a manual for this? I just grabbed the same compressor for $20 and want to make sure of parts and maintenance. Runs great after repairing a brittle electrical wire.
Magnum Air 5 HP 35 gallon Two Cylinder Compressor
One other question, do you know what belongs on the brass...