Gas Tank Repair: How to Permanently Remove Rust from a Gas Tank

What You'll Need
Pressure washer
Protective clothing, eye wear, and gloves
Muriatic acid
Baking soda
Isopropyl alcohol

Removing rust is the easiest form of gas tank cleaning. Follow the steps below to successfully rid your tank of any rust settlement. It is an easy process but utmost care should be taken while using the cleansing agents.

Step 1 – Park Your Vehicle in a Safe Location

A gas tank repair could go wrong if necessary safety precautions are not taken first. Start off by parking the car in a clutter-free environment, away from any flammable substances. Make sure the area is also well-ventilated.

Step 2 – Drain the Gas

The primary step in the gas tank repair is to drain all the fuel from the tank. Locate the drain cork at the bottom and unscrew it to let all the fuel flow out of the tank. Make sure you know a safe place to dispose of it and all other chemicals before you begin.

Step 3 – Remove the Fuel Lines

After draining the fuel tank, the next step is to disconnect the fuel lines—three in total. The first one is the supply line, which originates from the bottom of the tank and heads to the engine. The second is the fill tube that originates from the gas entry point, and the last one is the vent line.

Step 4 – Remove the Metal Straps

The next step is to unscrew the metal straps holding the fuel tank in place. Loosen the nuts with a wrench and pull the fuel tank out of the vehicle. It's that quick and easy.

Step 5 – Remove Loose Rust

Once the fuel tank is out of the vehicle, you can start with the rust removal process. However, before you introduce the rust remover, try and get rid some of the loose rust first. Get rid of some chunks by spraying a pressure washer directly into the fuel tank. Follow it up with some hot soapy water. Pour it inside and let it sit in the tank for some time before you wash it out.

Step 6 – Pour Acid Inside

Muriatic acid, or hydrochloric acid, works as a good rust removal agent. Be extremely cautious while using this product. The fumes released during the interaction of the acid and the rust are extremely harmful, so make sure you are wearing protective clothing, eye wear, gloves, and a facemask to stay safe. Keep the fire extinguisher within reach as well.

After cleaning the tank, pour in some water. The composition of water and acid should be about 1:1. Next, pour an equal amount of acid into the water inside the tank. Make sure the acid doesn't fall on the outer surface. Let the water and acid mixture rest for 30 minutes to an hour. After that, drain the liquid out of the fuel tank.

Step 7 - Neutralize the Acid

After removing the acid from the tank, it is important to neutralize the tank. Introduce a mixture of 1/4 cup of baking soda and two gallons of clean water into the tank. Let it rest for a little while, and repeat the same process at least six times to ensure there is no acid remaining.

Step 8 – Add Isopropyl Alcohol

Drain the tank once more and add isopropyl alcohol to it. Fill the alcohol to about 70 percent of the tank's capacity. Then, after letting it sit for about 10 minutes, drain the tank again. The alcohol will rid the fuel tank of any remaining water content.

Step 9 – Add Gasoline

Now pour gasoline into the tank. Let this settle for around 10 minutes as well, and then drain it and make sure to discard it responsibly.

Step 10 – Replace the Tank

Reverse the steps you used to remove the fuel tank from its fittings in order to put it back.

These chemical treatments should have removed any and all rust settlements from inside your gas tank. You may need to repeat this process if you notice rust buildup in your gas tank in the future.