Classic/Antique Car Repair: gas tank, car folks, fuel gauge

Question
I have a 1947 Plymouth special deluxe 4 door sedan and i am trying to find out how many gallons of gas the tank holds. i don't trust the fuel gauge. when the gauge shows empty the most gas i can get in the tank is 5 gallons.  thanks

Answer
The tank holds about 17 gallons.  Gas gauges are notoriously inaccurate on older cars.  It is possible to adjust them, but it is a hard job, and very dirty, because you have to drain and remove the tank, then take the sending unit out of the top of the tank and bend the float arm so that it reads "full" when the float is at the top of the tank, and "empty" when the float is on the bottom of the tank. At the same time, you would check for a pinhole in the float which makes the gauge read low, or perhaps an electrical problem in the sending unit - all of which are very common in old cars.

It depends how much this upsets you - you can drive that car about 150 miles between gas stops without worry, so if your odometer works, just ignore the gauge and enjoy the car, or else stop every 50 miles and just put up with the situation. If you can't live with the problem, then you'll have to "get out and get under" as the old car folks say.

Sorry - there is no good news on this subject!

Dick