Gas Tank leak question

[vycan]

Hello all, <This is not the common problem.> When I bought the truck I fueled her up and off we went. I started noticing a wet spot under the truck and a strong smell of diesel. Turns out the rear tank was leaking. I drained her rear tank, and the problem stopped once it was down to a quarter tank. How can I check for holes in the tank without dropping the tank? I also started thinking the drain pipe, or whatever the piece is called that connects the pipe from where you fill her up to the tank might not be seated correctly, but she fills up without leaking. I traced it to the driver side of the tank, but the mess was so bad i could not tell from where it came beyond that. She has a dual tank, so it is not a major issue yet, but here are my questions to follow up. If I have to drop the tank, can I use JB weld to fix her up? If not, is there a way to fix the old tank without needing to get a new one? Can they rust out? I didn't think fuel tanks rusted out. thanks

[usedtodrivechev]

yes they can. unfortunately i had a leak just before winter too. i ran the leaking tank dry then switched to the other one. took it home and put a jack under the tank then took the straps off to find it was a leak from a rust area that is touched by the strap. i think the rubbery seal just got old and water got stuck in there and rusted it a bit.

I know lots of people will yell at me for this, but i just cleaned it up real good, put some/smothered the area with that liquid metal stuff from permatex. then sprayed about 10 coats (over a couple of days) of that rubberized bed spray from a can. basically extremely cheap rhino lining. its been fine since. no leaks. I know my fix could allow it to come back, maybe worse. but i dont want to spend that much for a new fuel tank.

[Steve83]

Fill in your profile so we have some idea of what you're talking about. No US-market F150 uses diesel, so I can't imagine why any fuel leak would smell like that, unless you have some funky old gas in an unused tank.

[adrianspeeder]

It's a good thing I can remember yer cool crew cab shorty PSD, but ya can help out everyone else by making a signature with all yer info.

It's possible for a tank to have a hole, or the hoses on top to leak.

Adrianspeeder

[vycan]

Sorry about that...

[Bruce R Leech]

Nice truck

[Steve83]

At least now I know why it smells like diesel!

Originally Posted by vycan

How can I check for holes in the tank without dropping the tank?

Crawl under there with a flashlight & an inspection mirror, and follow the wetness up. Use carb cleaner to rinse away the diesel residue so it dries away, and then find where it starts to come back.

Originally Posted by vycan

If I have to drop the tank, can I use JB weld to fix her up?

You CAN, but it probably won't last long. If it's rusting, it's happening FROM the inside, so that's where the repair needs to be.

Originally Posted by vycan

If not, is there a way to fix the old tank without needing to get a new one?

There are chemicals available at motorcycle shops for repairing gas tanks, but as common as these trucks are in junkyards, I don't think it's worth it. Either buy an aftermarket tank (metal is good enough, but plastic isn't much more expensive) or just find a good used one. It'll last another 10-20 years.

[vycan]

Thanks for the compliment, Bruce R Leech.

Thanks for the carb cleaner tip on the diesel residue, steve83.

Are the plastic tanks resilient?

I saw the ones at JCwhitney, but thought, "metal dents... plastic cracks."

Anybody on here have experience with the plastic tanks?

My wife doesn't do any off roading, it's just road debris I'm worried about.

[Steve83]

Many new vehicles & quite a few from the late 80s-up get plastic tanks from the factory, so they're obviously good enough for DOT, EPA, & NTSB approval. Considering the legal liability involved with selling ANY gas tank, I'm confident that anything you buy for on-road use will do fine.

Personally, I prefer OE parts, but that's just me.

[Scraper]

I just replaced my rear tank (1995 F150). I found a used one for $50 (with a 30-day no leak warranty). Advance Auto had a new, steel tank for $98 that included the lock ring and o-ring. It came with a 1-year warranty.

Surprisingly easy to install, with the right fuel line tools.

S.

[vycan]

Hello all,
So I finally had a chance to check her out today. There is a fuel filler neck hose that was split. I ended up not needing to drop the tank. Although I wanted to run the fix by you guys to see if it was a bad idea:

I used RTV to fill the split, and taped it with tube repair tape. Thoughts?

-Vycan

[Steve83]

Silicone is NOT fuelproof. Replace the hose ASAP. You can get one off of just about any '80-96 F-series.

And you still need to add your truck info to your profile. Your signature doesn't appear with every post.

[vycan]

How do you make it so the profile always attaches, right now I have to click the box, and sometimes I forget.

As for the fuel proof thing... what happens? Does it matter if it is diesel rather than regular gasoline?

thanks

-Vycan

[Steve83]

You can set it in your profile to always check the signature checkbox automatically, but fill in your truck info, too.

I keep forgetting you're running diesel (especially with GAS in the thread title ), but I doubt silicone will stand up to that, either. I'd fix it right.