How to Repair a Rusting & Leaking Gas Tank

Gas tanks are often among the most neglected components on a vehicle. We rarely inspect them for proper condition or operation, since they occupy an almost inaccessible location underneath the vehicle. Yet when our fuel lines and fuel filters become clogged, and gas starts leaking from the seams of a tank, we must take notice and do something about it. The best time to address the problem is before the symptoms arise. Cleaning and sealing leaks in a gas tank offers dividends down the road in terms of the fuel system's performance and reliability.

Instructions

1

Place the vehicle in park or neutral with the emergency brake set. Disconnect the negative battery cable with a socket. Lift the vehicle with a floor jack. Pace two jack stands under the front frame and two under the rear frame. Use a hand siphon pump to drain the gas out of the tank into approved gas cans. Slide under the vehicle and loosen the clamp on the fuel inlet hose on the tank, using a screwdriver.

2

Place the floor jack spoon under the gas tank, flush up against the bottom side. Use a socket and wrench to loosen and remove the gas tank strap bolts. Have an assistant help you gently lower the tank just enough to gain access to the top of the tank. Unplug the wire jack to the tank sensor.

3

Use a fuel line wrench to loosen and remove the fuel outlet line from the tank fitting. Use pliers or a screwdriver to loosen the fuel vent hose, then pull it off the tank. Have an assistant help you lower the gas tank to the floor and move it out from underneath the vehicle. Drain any excess fuel from the tank and let the interior dry.

4

Place a drift punch on the fuel pump retainer ring and strike it with a hammer until the relief notches line up. Pull the electric fuel pump assembly out of the tank. Don gloves and a particle mask. Pour a few quarts of muriatic acid into the tank filler neck. Add about a pound of surplus nuts and bolts in the tank. Tape up all the holes in the tank with duct tape, double layering the tape over the fuel pump outlet.

5

Have an assistant help you shake the tank vigorously for several minutes. Flip the tank numerous times to let the nuts, bolts and acid etch the metal in the tank interior. Remove the tape and safely dispose of the acid into safety containers. If the solution appears extra rusty, repeat the process. Remove all the nuts and bolts. Flush the tank with clean water from a high pressure hose. Let the tank air dry, or use a hair dryer to speed the process.

6

Pour a few cans of high quality tank sealer into the gas tank. Tape all the tanks holes as you did before with duct tape. Turn the tank end-over-end and side-to-side to let the sealer coat the gas tank interior. If you wish, you can prop the tank on each side for an hour to let the sealer settle into a thicker coat. Remove all of the duct tape and pour the residual sealer into a safety container.

7

Place the fuel pump assembly back onto its mount and secure it with the retainer ring, hammering the ring in the opposite direction with the punch to tighten it. Assemble the parts to the tank in the reverse order you removed them. Have your assistant help you raise the tank and prop it with the floor jack, while you connect the sensor wire, insert the hoses, tighten the clamps and reattach the hoses and lines with the appropriate hand tools.

8

Refill the gas tank with reclaimed gas. Use the floor jack to lift the vehicle and remove the jack stands. Reconnect the negative battery cable with a socket and wrench. Start the engine and check for fuel leaks.