Air leaking from air tanks even though they are closed .

Yes, 1/4" pipe thread. Buy a new valve, put thread tape on the threads, R&R. Very simple fix, and a common failure.

Drain your tanks first before removing the old ones.

 

Keep a sprayer bottle with dishwash soap in the side box. Every truckstop sells little bottles of Dawn. Handy for windshields when the truckstop doesn't maintain the squeegee bucket. Also for finding leaks.

 

Those valves have a name


Why do they call it a petcock?

Etymology. Apparently from pet +‎ ####, because of its size.

 

Why?

Because it comes from the term Petty valve which was essentially a cone-shaped valve with pressure applied to seal it. Usually, the pressure comes from a spring.

The word ***** comes from what I was told, a nautical term about ship ballast valves.

It is as bizarre as jubilee clips, being another name for a hose clamp.

Or why Canadian Ford Model Ts and other cars used square drive screws but not US cars.

 

Roberson, inability to use the inferior Philips in Canada.

(I can’t remember the whole story but it was interesting to listen to) something about patients

 

Seems to be a premature leak. Usually, yer “petcock” doesn’t start leaking until you enter yer more senior years.

 

Ford had this habit of telling the supplier - you do what we want or you don't sell to Ford. The time savings alone justified the use of the Robertson screw but Robertson said that he can not have the license to make it, which I think was a mistake on Robertson's part, but he could use it for Canadian cars because Robertson's company could supply them consistently.

Here is the Wikipedia snippet on the issue - The Fisher Body company, which made the car bodies for the Ford Motor Company, was one of Robertson's first customers and used over 700 Robertson screws in its Model T car. Henry Ford, after finding that the screw saved him about 2 hours of work for each car, attempted to get an exclusive license for the use and manufacture of the Robertson screw in the US. He was turned down by Robertson who felt it was not in his best interest and shortly after that, Ford found that Henry F. Phillips had invented another kind of socket screw and had no such reservations. Although the Robertson screw is most popular in Canada, it is used extensively in boat building because it tends not to slip and damage material, it can be used with one hand, and it is much easier to remove/replace after weathering.

When I got my 1930 Chevy Oshawa-built car, it used the Robertson screws everywhere. It was not a common screw here in the States so I went to Canada and bought a short pallet of assorted screws from a supplier. This was back when Customs was nice people - 1975, so bring it back, it wasn't even questioned. When I was given a model T (pile of parts, actually), it had the same screws so I knew it was Canadian built, and it was confirmed by the wider axles. That car was one of the most dependable cars I owned other than my Prius.