My fuel had isn't working right. When I fill it up it doesn't go all the way to full. It goes just a little over 3/4. When it shows empty I still have half a tank or so. I put a new sending unit in the tank after the gauge stopped working and now I got this. I'm getting closer to a functioning fuel hand.lol What do I need to do?Any ideas?

 

either the new sending unit is incorrect (wrong resistance range) or the float could have a small pinhole allowing gas to enter..making it heavier and therfor won't "float" as high in the gas...

 

If its new, it should of came with a new float, correct ? Have you cleaned the frame ground ? Did the float arm get bent in the installation process?

 

They don't come with a float afaik. Replacement sending units are often adjustable for calibration of the gauge indication by means of a set screw on the float arm. Don't bend the arm.

 

Genuine Ford fuel tank sending units come with the float and gasket, so do Carpenter's repro's.

Dunno if any other the other repro parts sellers/auto parts store replacement sending units come w/the float...or not.

 

"They" didn't when I bought one several years ago. I used a cork, that worked for a while but eventually sank.

 

All Ford fuel tank sending units come with the float. If you bought one without the float, someone robbed it.

If a customer came to the counter and needed a float and the dealer was ought of stock, it was common to rob one from a sending unit.

Most partsguys remembered to replace the missing float, but some forgot. The float and the gasket were also available by themselves.

The float is the same: 1957/79 Passenger Cars/F100/350's; 1961/79 Econolines & 1966/79 Bronco's.

Pics of sending units in DC's 1967/79 truck catalog (page 41 in DC's 2011 paper edition) show the float with the sender.

 

also check to make sure the ground for the sending unit is good.

 

I bought it from Napa and yes it came with a new float. I don't see how it could have got bent installing. I will check the ground today.

 

No, some people bend the arm (on purpose) to try and calibrate the gauge indications. Instead, use the set screw provided to adjust float height. In particular, bending the arm won't work if the gauge reads low with a full tank.