Grease for air pump for fuel tank

[prew62]

Just purchased an air pump for my fuel tank to replace the one missing on my 1911 Chalmers. Was hoping to find out what oil or grease those of you who use hand pumps, use.

Thanks!

[Henry K. Lee]

Vaseline is what I have always used!

Hank

[Dan McEachern]

If it has a leather disc for a piston seal, use neatsfoot oil on the leather. I do admit to a little machine oil from time to time though.

[Kaiser]

Vaseline or neatsfoot oil may work great on an airpump, but gasoline fumes might dilute them, when using the airpump on a gas tank.
you could try the grease designed for use on gas valves, it is called 'EZ turn' and i believe Lang's sells it, it won't dissolve in gasoline, and an old trick ; a bar of soap might work, it's slippery and won't dissolve in gas, used it in the past to lubricate gas valves and even did a temporary fix on a carb float once to help a buddy get home.
His carb kept flooding, turned out he had a tiny pinhole in the float so it slowly filled with gas and sank, flooding the carb.
We drained the float ( took waaay longer than filling it, shaking the gas out through the pin hole) then gave a good coating with a bar of soap from the restroom of the gas station where we were stopped and it got him home the last 30 miles or so.

[YellowTRacer]

Right or wrong I've been using 30 wt. engine oil for 50+ years with no problems. Learned it from the old timers

Ed aka #4

[DanTreace]

Most older publications state to use vaseline for the cupped leather washers in air pumps.
Oil can work in the leather and make it soft, giving poor sealing.

[Mark Gregush]

From the Colman Company for care of the pump;
When it's time to take out your lantern, remember to oil the pump cup on the tank's pump plunger at least twice a year with a light machine oil. This allows the cup to seal against the inside of the pump barrel and insures the pump will work smoothly and push air into the tank properly.
They have a leather seal and are just as close to the fuel.
So now I have a question; is the leather piston in these a flat disk or cupped? If a flat disk I can see using just Vaseline, with the cupped type I would think it would need to be flexible so the air pressure on the down stroke can push against the side wall for sealing. The tire pump, Colman stove/lantern and lead melting burner all have cupped leathers and I have been using oil on them.