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leaky rear gas tank

tomtoc

tomtoc

2,049
68
Springfield, MO
went out to go somewhere an hour or so ago and i noticed a gas sell. looks like the rear tank has a slight drop. like 1 drip every 30 seconds or so. it's right under the right rear tank strap somewhere.

i'm not putting a ton of work/money into it....
can i put some jb weld or equivalent on the outside? anyone done that with success?
safe to drive the rest of the tank off and use it on long trips still dripping?

i figured for just cruising around town every day i can just use the front tank.
 
tomtoc

tomtoc

2,049
68
Springfield, MO
crap, someone please move to gen 8/9, no idea how i got it here, but i guess if someone wants to buy a leaky tank that'd be fine too
 

Brian_B

blank
6,833
84
Mountain Home, AR
Don't get rid of it. Go to any parts store (I use O'reilly most) and get some gas tank epoxy. I fixed several pinhole leaks on my 88 F-150 years ago and it still does not leak.

I basically covered one corner with the stuff. The tank was rusted under where a plastic cap thing sat over the end and held water.

It is dads truck now though, so I know it does not leak.

It is in the classifieds...OOPS!
 
Fellro

Fellro

Moderator
Staff member
7,953
361
Iowa County, Iowa
I fixed mine with JB, but I had the tank off to be sure that there wasn't any fuel to contaminate it. I cleaned it up real good to be sure it had a clean surface to seal to. You may want to take a wire brush to the strap areas to be sure there isn't any more holes forming. If no more holes are coming through, then spray it down with undercoat to prevent more from forming.
 
tomtoc

tomtoc

2,049
68
Springfield, MO
i'm still going to try to fix the thing this weekend - just doesn't make a lot of sense

filled it up tuesday morning (it was bone dry)
first time i noticed a leak was thursday night..and it was from the smell
looking out the window today at work it hasn't dripped at all.

it was obviously its fullest tuesday and didn't leak. would temperature cause it to leak? even then...why would it leak after dusk but not in the heat of the day or in the morning? i park basically level at home and at work. i guess the tank itself could be cooling and shrinking at night opening up a hairline crack - i'll see if i can look tonight.

also - i assume the tank needs to be bone dry to do this?
will 1 strap hold the tank up if it's empty?
 
john112deere

john112deere

caffeine junkie
Staff member
10,807
405
central Vermont
Are you running off the front tank or rear?

Gas and it's vapors do expand significantly in the fluctuation between nighttime and daytime temps, and if you filled it to the top in the evening, a warm day's expansion could make it leak.
 
fords4life91

fords4life91

"The best NEVER rest"
119
3
Shelby Twp. MI
HAHA my truck leaks in THE SAME EXACT PLACE!! lol IM just gonna buy a new tank tho, there only 100 bucks so to me its just better to buy the whole thing!!
 
blacksnapon

blacksnapon

Moderator
Staff member
9,461
301
waynesville,mo.
Get Gutsy!!!!!!!!!!WELD IT! I've welded a bunch of them. You have to have nerves of steel however. Of course empty it.......although I've done a few with fuel in them. Then using an exhaust hose, put one end in the tank, and the other end on the tailpipe of something not running rich. Start it up, and let run a while. The fumes are what will get you in trouble, and this evacuates them sufficiently to braze the tank up. If the hose comes off, stop welding. When you look up, no one will be around you!
 

eco

646
12
Even though gas vapors expand with temp changes, the tank is always vented via the evap system. So, if pressure does build up it will quickly exit through the vent hose. So I don't see how temp changes could cause a leak to appear.

In order for an epoxy (JB Weld or whatever) to work well, I would think that the surfaces that you apply the epoxy to would have to be wire brushed and cleaned very well with a strong solvent (paint thinner, carb cleaner etc.).

Obviously, the only real long term, fool proof fix is a new tank and they only cost about $100 - thats how much the tank was for my van. They arn't that much work to replace either assuming that the tank doesn't have much fuel in it.
 
tomtoc

tomtoc

2,049
68
Springfield, MO
100 isn't too bad. I bought some tank paste crap. We'll see if I have time to play with it tomorrow. I just went out and looked at it - no drips, just moist
 
tomtoc

tomtoc

2,049
68
Springfield, MO
tomtoc said:
I did - just bought this Monday. That's why I've started 100 threads this week.
Click to expand...
well, not quite tomorrow, but i did it on wednesday.

i took the strap down and didn't see an obvious crack or anything, but i cleaned up where it had been wet and put the patch kit/epoxy all over the thing.

long story short, it's 10x worse than it was before. i'm thinking the leak is in the front of the tank, up where i can't see it. it got worse when i installed the bumper (impact gun shaking the truck), then it got worse yesterday (i was pounding on a wrench trying to get the straps off). it's got to be a crack somewhere that's just getting bigger.

i might do the bronco tank swap, but if i do, i'll start a new thread or dig up one of the old ones for questions. stock tank or bronco tank, would you guys trust a junkyard tank, or just try to buy a new one?
 
tomtoc

tomtoc

2,049
68
Springfield, MO
i just called one a little while ago and they said they had one for $90. they didn't mention a hole - doesn't mean there's not one there, just that they didn't say anything.

i don't remember if it was $70 or $90. if that's the case with all of them, i might spend another $60 or so and get a plastic one to never deal with rust again. i'll spend $150 for a new tank, but i'm not spending that plus another $150+ on the parts to do the bronco swap.
 

Gas Sucker

12
0
tomtoc said:
i'm still going to try to fix the thing this weekend - just doesn't make a lot of sense

filled it up tuesday morning (it was bone dry)
first time i noticed a leak was thursday night..and it was from the smell
looking out the window today at work it hasn't dripped at all.

it was obviously its fullest tuesday and didn't leak. would temperature cause it to leak? even then...why would it leak after dusk but not in the heat of the day or in the morning? i park basically level at home and at work. i guess the tank itself could be cooling and shrinking at night opening up a hairline crack - i'll see if i can look tonight.

also - i assume the tank needs to be bone dry to do this?
will 1 strap hold the tank up if it's empty?
Click to expand...

I had the same problem in my last truck, found out the seal on top of the tank for the fuel pump was leaking. I would only smell/ see gas after a fill up, but after using a few gallons no smell or gas. I just wouldn't fill my tank all the way- problem solved. One stap will hold the tank fine, they are not heavy at all (empty of course) I undue one strap and let it hang when thery are full to access the pump even.
 
tomtoc

tomtoc

2,049
68
Springfield, MO
summit appears to have the best deal ($110)
http://store.summitracing.com/partdetail.asp?part=RNB-576-121

only other one i'd consider is from bronco graveyard ($130)
http://broncograveyard.com/bronco/i-30330_rear_tank__p_u__19_gallon_plastic_3_5_8_in__hole_90-96.htm
good thing about that one is it's plastic.

either one of those should work, right? do i need anything other parts, or is it a direct swap? new seals, straps, etc? i can just reuse all that, right?

i like the idea of plastic, but this one lasted 15 years, if i get half of that out of a new steel one, i'll be happy. that said, i'm leaning towards the summit steel one.

someone give me the nod, i'm ready to place the order
 

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