Fuel gauge

[rob1950]

Hi Guys
Need some advise on fuel gauge problem
1998 GU 4.5 on LPG
The sub tank gauge is connected to the gas tank and seems to work OK.
The main fuel gauge sits on 1/4 and doesnt move even though the petrol tank (Sub tank) is full.
Any ideas all advise on what to look for appreciated

[04OFF]

At first guess, id say the tank sender unit is faulty, when i first got my GU (4.5 petty) the main fuel gauge would not read full , i removed the sender unit, cleaned (sanded with 1500) all the contacts, plus added a little more tension to the slider needle, and its worked perfect ever since !

[rob1950]

To remove sender unit does the fuel tank have to be taken out ?