Tire pump question . . .

[Rich P. Bingham]

Like many, I picked up a real Ford tire pump for my Lizzie. I would like it to be functional. Seems to be a good restoration, plunger piston has been replaced with a cup from a hydraulic brake cylinder, it moves air well.
Fitting to attach to the tire stem doesn’t have a point for opening the stem valve. Referring to the Dauntless Geezer’s notes on this subject, air pressure generated by the pump is supposed to pass the stem valve, which then acts as the check valve to enable tire inflation. This doesn’t seem to be the case. What am I missing ?

Hose attachment to tire stem

Pump base cavity showing outlet aperture

[DanTreace]

This older post covers most of those questions. Your hose fitting seems correct and original.


viewtopic.php?t=15994

[Rich P. Bingham]

Thank you kindly Dan. I did try to search the forum, did not find that thread. It seems definitive, wonder why I can’t seem to get enough pressure to open the tire stem valve ?

[TXGOAT2]

I think it would work a lot better with a leather cup instead of the rubber one. The leather cup will allow air to pass it on the upstroke. The rubber one might not, leaving you with a partial vacuum in the pump barrel instead of a charge of air to compress.

[Humblej]

The modern schrader valves are different than those 100 years ago. Modern valves will not take air without the center pin in the air chuck, old valves do not need it.

[Rich P. Bingham]

Pat, I have a hunch you’re right about the rubber. Pretty much what I’ve found to be the case, Jeff. . . So, is there a remedy ?

[Steve Jelf]

A few years ago when I pumped a clincher up to 72 psi with the hand pump, the Schraeder valve in the stem was all the check valve I needed. My pump's hose connector that screws onto the stem has no center post because that would hold the valve open and the air would come back out. I can't imagine that in the last couple of years the design of the valves has changed after more than a century with no changes.

This makes me want to get back out in the shop and investigate.

[TXGOAT2]

Modern valves will take air without depressing the pin... IF you have enough pressure. A hand tire pump may not develop enough pressure, especially if the tire has some pressure in it. All hand tire pumps I've ever used have a device to depress the pin in the valve core. I used to have several Golden Rod pumps and a few others which I used on bicycle and car tires. Some of those pumps probably dated to the 1930s. I believe they all had a pin type chuck and a check ball in the base. The chucks and hoses may not have been original on the older ones.

[Allan]

If there is a pin to push the valve core stem down, there has to be a check valve on the pump. Otherwise, as Steve said , what you push in on the downstroke simply comes out again on the upstroke. On the inside end of early valve cores there was an external spring on an extended pin in the centre. Perhaps these are what you need for a hand pump to work.

Early bicycle valves had a close fitting rubber sleeve over a centre shaft. As air was pumped in, the sleeve was expanded to allow air in. On the upstrioke, pressure in the tyre forced the rubber sleeve to close the inlet passage. The cycle was repeated until the tyre was inflated. In this application the rubber sleeve was the check valve. Later "easy pump" valves did away with the rubber tube in a revised design.Both these types of valve cores required slots either side of the brass stem, and corresponding lugs on the side of the valve core. These were superseded by the car type valves and stems.

Allan from down under.