gas tank repair

Gastastrophe! JB Weld Gas Tank Repair Guide

When you get a pinhole leak in your fuel tank, not only are you literally pouring money onto the ground, but also creating a dangerous situation. Repairing a fuel tank can get difficult, especially when the it is full of fuel. Not to worry, there is a temporary solution to your fuel drip problem: gas tank repair. While the real solution is to replace the fuel tank, that is not always feasible in the short term. Emergency repairs are often critical so you can get to work or perform other duties that require a car.

Repair Options

Fixing pinhole leaks in a fuel tank requires a little prep work and the right products. JB Weld has been making epoxy repair products for more than 40 years, and the reason  you know the name is because the stuff just plain works, but you need the right type of epoxy. Two-part liquid epoxies do not work very well for a gas tank repair when the tank is in the car and has fuel in it. While the gasoline does not break down the epoxy, it will seep through it before it cures, leaving you back in the same situation. What you need for a wet repair is JB Weld Autoweld or SteelStik epoxy putty stick.

JB Weld Steel Stik is easy to use, and because it is in a putty form, it is stable in your glovebox for emergency repairs too.

JB Weld Steel Stik is easy to use, and because it is in a putty form, it is stable in your glovebox for emergency repairs too.

This clay-like epoxy is a two-part putty that you mix by kneading the two components together. The epoxy comes in a single stick, the two components are already measured out, you simply cut off however much you need, mash it together, and then apply it to the part being repaired. The epoxy hardens after five minutes, and is fully cured in one hour.

Because the epoxy is clay-like consistency, fuel (or other liquids) can’t seep through it or around it. Once cured, the epoxy can withstand 300-degrees and 900 psi of pressure, so it will be perfect for your leaky gas tank. This is the fastest way to keep that expensive fuel in the tank and not on the asphalt.

Supplies

JB Weld also makes a gas tank repair kit, which consists of a tube of epoxy putty, fiberglass cloth, sandpaper, and an applicator. This repair is the same as the SteelStik, but adds some additional strength with the fiberglass. This is best used in larger repairs or on a tank with multiple pinhole leaks.

Repairing your tank is easy, you do need a few things before you get started:

  • Epoxy putty
  • Sandpaper (80-180 grit is fine)
  • Absorbent towel (red shop rags are not absorbent enough, use paper or terry cloth)
  • Can of brake cleaner or carb cleaner (optional, but a good idea for a better repair)
  • Pencil

Getting Started

Begin the process by locating the leak. Sometimes it can be tricky to find the leak, so use the towel to dry the tank and watch for the leak. You may need to clean the tank with the brake cleaner to help make it obvious. Once you find the leak, mark it with the pencil.

It is hard to see, but there is a small hole in the upper right center of the fuel tank sump.

It is hard to see, but there is a small hole in the upper right center of the fuel tank sump.

Clean the area around the leak. You want to clean at least three inches around the damaged area. Use the sandpaper to sand the tank, covering the entire three inch area. Take it down to bare metal. The sanding does two things – cleans any paint, rust, and road grime from the gas tank repair area, as well as gives the epoxy something to grab onto. It works better than smooth metal.

Using a sanding block, the paint and rust scale was removed from the tank.

Using a sanding block, the paint and rust scale was removed from the tank.

 

Here's a better look at our pinhole leak.

Here’s a better look at our pinhole leak.

Spray the area with the cleaner and wipe it down. You will likely have to do this several times.

Using some CRC non-chlorinated brake cleaner, the area was cleaned and wiped dry.

Using some CRC non-chlorinated brake cleaner, the area was cleaned and wiped dry.

Cut off an amount of epoxy that you think will cover the repair. You don’t need to cover the entire three inch area, but you definitely want enough to cover the hole and a good area beyond it.

Using a razor blade, a small amount of SteelStik was sliced off and the wrapper removed.

Using a razor blade, a small amount of SteelStik was sliced off and the wrapper removed.

 

Knead the putty to mix the two colors uniformly. The color should be a dark gray.

Mash the compound together until it is a uniform light grey color.

Mash the compound together until it is a uniform light grey color.

 

Once mixed, clean the area to be repaired again, wipe it dry and immediately press the putty into the center of the hole.

Press the putty to the tank. It will still be leaking, that is okay. Work the putty into the hole and press the edges down around the area until it seals the leak.

Press the putty to the tank. It will still be leaking, that is okay. Work the putty into the hole and press the edges down around the area until it seals the leak.

 

Work the putty flat against the tank, ensuring the hole is sealed. You don’t want a big glob on the tank, you want it to be smooth and flat.

Continue to work the putty on the tank until it smooth and all the edges are secure.

Continue to work the putty on the tank until it smooth and all the edges are secure.

 

The putty should harden in five minutes, and fully cured in one hour. Wait at least an hour to drive the car. We suggest watching the tank for leaks over the next 10-15 minutes, and then check it after the hour has passed. Your gas tank should now be repaired and ready to drive. Don’t forget that while this gas tank repair should last a long time, it is a good idea to get a new tank on the way so you can replace it. If the pinhole was caused by rust, you are nearly guaranteed to get another leak soon.

The final results yield a secure repair until we can replace or weld the tank. We left the tank full after several weeks and the repair still holds.

The final results yield a secure repair until we can replace or weld the tank. We left the tank full after several weeks and the repair still holds.

Check out all the JB Weld products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on gas tank repair, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.

about author

Jefferson Bryant

A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 4 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced.

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