I did all the obvious things such as changing out the fuel filter and pump which at first seemed to solve the problem but it came back.
Finally I pulled out the fuel tank sending unit which was rusted up good clogging up the lines.
I was lucky enough to have a wooden bed in the truck I worked on so was able to pull the boards up to help remove the Fuel Tank.
Most trucks will not have this option and need to drop the tank from under the truck.
I ordered the sending unit from eBay which saved me money. Be sure to call around and see whats the best price for your location.
After pulling the unit the old gas line was in bad shape and is cheap so I also replaced it.
It uses a 5/16 Fuel Line which I ordered from Amazon.
Here is the Fuel Line I ordered on Amazon.
LDR 516 F5165 5/16-Inch ID 5-Feet Bag Fuel Line
How To Replace a Fuel Tank Sending Unit on a 1970s Dodge Truck
1… The sending unit is located on top of the gas tank. Depending on the truck body style the tank will likely need to be dropped.
The bed on my 78 is wood so I didn’t have to drop the tank but still did to be sure all the rust was flushed out.
If you can get to the tank from the bed as I did this is the best option otherwise the tank will need to come out.
There was three straps holding the tank in with the bolts rusted up good.
I also drained all the gas out with a spare electric fuel pump I had laying around.
The tank is plastic so as long as it doesn’t leak it will only need a good cleaning. Also be sure to check the inlet pipe were the gas goes in for any rust, mine was rusted good.
2… Unscrew the hose clamps and the wires. The sending unit is held in place with Philips screws which simply unscrew to pull it out.
3… The unit simply pulls out.
4… I ordered a new unit from eBay since it was the best low-cost option for me. Check around to see what is the best price for you.
I compared the old unit with the new one which were the same.
The new unit also came with a new gasket.
5… Bolting it in is straight forward with the gasket and tightening the screws. It only goes in one direction.
6… The old gas hose was in bad shape so I replaced it with a new 5/16 gas line hose.
After flushing the gas tank and installing the new sending unit it solved my gas problem and is running good again.