the rear fuel tank on my truck is leakin (diesel) i was wondering if there is a way to patch it or will i have to buy a whole new tank. t
thanks

 

I have patched tanks with JB weld. It has to be clean and dry for it to work. Price a new tank at Autozone or whatever you have in your area, they're pretty cheap.

 

You can also use JB quick weld, it will dry faster and really holds.

 

I'm assuming it's a steel tank. If so, not difficult to patch at all so long as you know how to weld.

First drop the tank, make sure it's completely drained, and give it about a week for all the fumes and residue to dry out.

Next you'll want to make sure you've removed all the rusted part of the tank. Using an angle grinder, cut out the area that's leaking. Clean up the edges of the area you cut out about 3 inches using a wire brush, or you can sandblast if you want. Just make sure the steel is good and clean for welding.

Fabricate the patch so that it has about a 1 inch overlay. Tack weld 2 corners to hold it in place, then make sure the patch is good and flat against the tank and weld one side. Then make sure it's good and flat against the tank and weld the second side. Continue the process for the remaining sides.

After the weld has had time to cool, fill the tank with water as full as you need to check for leaks. Any leaks can be welded over or you can use JB weld if you wish.

This is the procedure I use for patching holes. If it's a crack, you might try welding the crack directly.

I would only recommend this if you know how to weld. It's too easy to burn through the steel if you don't know what you're doing.

 

i still need to drop the tank and depending if it is very rusty ill replace it but if its not that bad i will try the jb weld.
thanks

 

Try something like magnum steel epoxy. It will hold up better than JB weld around fuel.

 

Jb weld and jb quick are gasoline proof. I actually prefer the quick also, the regular stuff takes FOREVER to set up. I had a customer vehicle come in one time late on a saturday with an old crown vic or ltd or something. It had a steady drip of gas coming from the bottom of the tank from a hole that had rusted through from the inside. I sanded the area with some 80 grit, then to keep the fuel from dripping from the hole, I found the vent line going to the charcoal canister and hooked it to manifold vacuum. With the engine running I saw that the fuel leak stopped and I assumed air was being pulled in the hole because of the vacuum in the tank. Mixed up some JB quick and smeared on the hole and an inch or 2 around it, then stuck a small square of thin cardboard over the area so it wouldnt suck the jb weld up into the tank. Let it run for an hour or so while the epoxy set up and it held. I worked on the same car a few times over the next couple years and the repair was still holding.

 

Napa sells stuff to fix little holes like you said, it works fine with diesel too. Know this first hand, drilled into a combine fuel tank before by accident and had to patch her up