In the fuel tank
To change the fuel sending unit on a 1981 Jeep CJ7, first, disconnect the battery and drain the fuel tank. Remove the fuel tank by unbolting it and disconnecting the fuel lines and electrical connectors. Once the tank is out, take off the sending unit by removing the retaining ring and lifting it out of the tank. Replace it with the new unit, reassemble the tank, and reconnect everything.
Remove the gasoline from the gasoline tank. Remove the fuel line from the gasoline tank. Remove the fuel sending unit retaining plate. Reverse the process to install the new fuel sending unit.
you have to remove rear seat ,under the seat there's two covers , one is for the fuel pump , the other is for the fuel gauge sending unit .Remove cover on passenger side and remove fuel gauge sending unit .
The only way to gain access to the inside of the fuel tank would be to remove the tank from the vehicle then remove the fuel pump/sending unit assembly from the top of the tank.
Lower the Gas tank. Remove the sending unit/fuel pump from the tank and replace the unit. The sending unit and fuel pump come together.
Remove the fuel tank and then the sending unit. The fuel pump is on the fuel sending unit bracket.
Try replacing sending unit
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Run the truck until you have less than a 1/4 tank of fuel or siphon the fuel out. Remove the front seat. Remove cardboard cover that covers the fuel tank. Disconnect wires and fuel line to sending unit. Remove the sending unit from tank. Reverse for assembly.
you have to remove the fuel pump it is connected to it, it has to be replace as one unit
You have to remove the fuel tank.