First, make sure that both tanks have the same number of fittings on the topside dome to the right of the fuel inlet hose.
In a well ventilated area that is completely free from any open flames or other ignition sources, drain the fuel out of the tank. It's acceptable to use the car's own fuel pump for this but bear in mind that debris may block the pump or fuel lines. Alternately, on the bottom of the tank is a turret that protrudes down through the floor of the trunk. From underneath the car, unscrew the turret's plug, and use a large funnel to catch the fuel as it gushes out. (If the fuel does not gush out, the turret is blocked with rust or other debris.)
Store the removed fuel safely in an approved container. If you're adding the fuel to the tank of another vehicle, particularly a modern one using fuel injection, I very strongly advise filtering out any rust or other debris during the transfer.
Disconnect the various small hoses on the top of the tank, noting where each one goes. The drawings in the shop manual and parts book are particularly unhelpful here. It may be easiest to use lengths of masking tape with the appropriate text written thereon, or you may wish to make a sketch.
Loosen the hose clamps that secure the fuel inlet hose to the fuel cap and fuel tank. Pull the fuel cap upwards to remove. Prise the big rubber grommet from the bodywork, taking care not to damage the paint (when possible, this is best done from inside the trunk, rather than from the outer surface of the car). Remove the fuel inlet hose.
Disconnect the wiring and fuel hose from the fuel sender/outlet assembly on the left side of the tank. While it is possible to replace the sender assembly with the tank in the car, it's easier once the tank has been dismounted.
Remove the four 1/4" bolts securing the fuel tank securing straps to the car. Remove the straps. The fuel tank may now be lifted free of the car.
If the new tank has a known-good fuel sender/outlet assembly, you can use it. Otherwise, you will want to transfer the assembly from the old tank to the new one. To do this, tap the assembly's securing ring COUNTER-clockwise until it can be removed from the tank. Prise the assembly and its gasket loose, then rotate and twist the assembly as necessary while pulling it free and away from the tank. When installing the unit in the new tank, place a thin coat of fuel-resistant gasket sealer on either side of the rubber gasket. If there is later any fuel leakage or seepage whatsoever at this point, a new gasket is indicated.
Before installing the good tank, I strongly advise removing the water-absorbing, rust-promoting felt that the factory placed between the tank and the floor of the trunk. In my car, I glued many inch-wide strips of ribbed rubber stair tread to the bottom of the tank, giving considerable air space between tank and trunk floor. I also lined the areas of the tank that bear against the securing straps with additional lengths of the same material to permit a good firm mounting for the tank without distorting it. The tank ended up about 1/8" lower than its initial location, which made the fuel inlet parts a bit easier to replace.
Do not install the fuel tank securing straps until the fuel inlet hose, grommet, and fuel inlet cap are installed and secured.
It's probably a good idea to put a fuel filter between the tank's fuel outlet and the inlet of the fuel pump.
Last edited on 05-07-2005 06:56 pm by Mark Rosenbaum