driver's side fuel tank leaking - 99 FLD

Finally got on this today. Ran the truck low on fuel, cleaned the fuel from the leaky area and bottom of the tank and then raised up the front end letting it sit that way a few days while I slacked off and double checked to make sure it wasn't leaking still with that lower fuel level. It wasn't.

Had a helper use my leaf blower sealed up with rags in the filler hole while I sprayed with soapy water. Quickly located the leak. It was in a seam on the oval shaped aluminum piece that was welded in there with the bungs in it. But it wasn't in a weld.

In the pic below the circle is where the leak was all epoxied up. The other pic the arrow points to the seam part that was leaking, but that's not the actual leak area it's just the upper part of it above where I epoxied the leak.

Cleaned with acetone, sanded the area with 120 grit then some 80 grit. Cleaned again. Epoxied with 6 minute jb weld grey. Letting it cure overnight and then I'll point the truck facing downhill to check if it leaks tomorrow. Should be good to go. Great idea with the leaf blower pressurized it to find the leak!!

 

Lol it had about an 1/8" of oil/dirt coating everything. Almost looks like factory new after some solvent and scrubbing.

 

Yeah it's weird but that's where the tell tale bubbles were coming from.. I'm not going to pull a ****ing fuel tank off until I absolutely have to. All these guys saying its probably pitted and corroded under the straps.. ..well that is probably so, but I'll just wait until it springs another leak to deal with that one. I'm thinking all that oil slobber from the old engine maybe acted as preservative and stopped that haha! It ain't broke so I'm not fixing it.

My brother works at a place that welds on aluminum fuel tanks every day. He says the crack is always at a weld and normally always at the start/stop point of the weld. Says they will take a die grinder to clean out the crack there and just re-weld it but sometimes chasing that one crack/leak just leads to the frustration of more cracks developing. Says they pressurize to check for leaks. Said if mine needs welding to just pull it off and bring it to him they will fix it right up.