Pictured here are the original Ford service tools used by dealers to remove and install the inner and outer nuts on the cowl tank gas gage.
These are forged steel tools and are designed to fit the nickel plated brass nuts properly and securely without damaging them. Many reproduction wrenches are soft aluminum and poor fitting. The reproduction tools can easily slip off the nuts and damage the finish of the nuts.
The outer nut wrench is Ford service tool number 5-Z-1825. The outer nut wrench is a ten sided socket.
The tool number for the eight-point inner star nut wrench is 5-Z-1822. It was later changed to 5-Z-2031, which was a square drive wrench.
Here is a closer picture of the 5-Z-1822 inner star nut wrench showing the eight point shape, as well as the concave end of the wrench.
The concave end was made to clear the convex magnifying lens used on some 1928 and 1929 gas gauges. Most gas gauges used flat glass lenses.
Shown above is the later 5-Z-2031 square drive wrench for the inner gauge nut. Thanks to Gary Anderson of Minnesota for his permission to post his 5-Z-2031 photos here!
What is the purpose of the little stem on the end of the handle?
This close-up view also shows the 'H in Diamond' logo of Ford's tool manufacturer, Herbrand.