Al, if there is direct metal-to-metal contact I would definitely add assembly lube. The way these pumps are made, (with non metallic piston "ring") I don't think it is necessary.

Troy, your air cleaner sounds like a pretty good score! I agree, these pumps are very simple. And with the way they are designed, they can be rebuilt almost indefinitely.

"Forget pounds and ounces, I'm figuring displacement!"

If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.