mustang ii      
Mustang II Fuel Tank Replacement     by Rob Milton
First of all, the aux. tank actually makes it easier to change the main tank. The removal process of the main tank should go like this...

1. Remove any gas from the tank. If you are unable to siphon with the tank in place, you can do it at a later point.

2. Attempt to loosen, but not remove the tank strap bolts. This can be difficult due to rust. Make sure you use plenty of WD40. You will need a deep well socket. The design of the tank strap bolts can also make removing them difficult. They have square ends and tend to turn while you are loosening. If this happens, you will need to slowly turn the bolt until it rests in the square hole it is inserted into. Then you should be able to loosen it. Use a thread-chaser on the exposed portion of the bolt (prior to attempting to remove) to assist in removal if they are rusty. If this still doesn't work, it is best to cut the bolts. Removal can be nearly impossible.

3. With the tank hanging loose, disconnect the wiring harness from the sending unit and remove the rubber fuel line. (Only remove the line if the tank is empty, otherwise, remove it after emptying the tank at the point I explain.) You should replace the rubber line and clamps, as they tend to deteriorate over time. I should point out that you can drain the tank through the fuel line by cutting it and letting gravity do it's job, but this will take a long time.

4. Now you should remove the filler neck pipe that goes directly into the tank. A large channel lock pliers works well here. This can be difficult due to corrosion and rust. The trick is to spray (soak) it with wd40 at the point where the pipe meets the rubber gasket in the tank and then grip the filler tube with the channel locks or even a pipe wrench and turn it until it moves freely. Now you should be able to pull the tube out of the tank.

5. Now you have direct access to the tank and you can drain it if you haven't yet. If the tank is full of gas, you should not remove this. Drain it through the line that connects to the sending unit. Remember, this will take time.

6. Now you can remove the strap bolt nuts completely and drop the tank. It is best to position a floor jack under it to help it along.

7. Spray the vent tube assembly on top of the tank with wd40. Disconnect the vent tube from the top of the tank. This may need replacing also due to age.

8. Now you can remove the tank.

9. Remove both rubber gaskets from the tank. Replace them if they are brittle. This is the major contributor to rusty tanks...

10. Remove the sending unit. The sending unit is held in place by a retaining ring. You will need to hammer/chisel on this ring to turn it. Don't be afraid to hit it. This may be difficult due to rust. Once the sending unit is removed, inspect it to make sure it isn't rusty or broken. These tend to be bad if the tank is bad, but not always. If your gas gauge wasn't working, it needs replacing. If it was working and is rusty, it can be reused, but be sure to remove as much rust as you can before reinstalling it. Also, save the rubber o-ring. You will need it for the new tank.

11. Now you can prepare the tank for re-installation. On the exterior, I recommend a good cleaning, rust removal and neutralizing the rust with a diluted muriatic acid solution. Por-15 also makes a pre-paint solution called "metal ready" that can be used. Paint with enamel, and then rustproof with a rubberized undercoating.

12. Use petroleum jelly to lubricate the grommets for replacement and reinstallation. This especially important for the filler neck tube because it is difficult to reinsert the tube while lifting the tank into place.

13. I recommend using bike inner tubes to install in between the straps and the new tank. Although, there is no friction or noise issue, this is an area on the tank that always rusts due to moisture being trapped between the strap and the tank. The rubber will seal this area.

14. Get the tank back under the car. A small floor jack works well to guide it up and into place and it will allow you to reattach the vent tube and the insert the filler neck. Don't worry about attaching the gas line until you get the tank in place. Now you can bolt the straps back on, reattach the line to the sending unit.

  Copyright 1999 - 2015 Mustang II Network  -  Privacy Policy