Steel Fuel Tank with Crack

Caver Dave

Caver Dave

Just holdin' it down here in BFV
Moderator
Joined
Mar 10, 2005
Location
Hooterville (24171)
Well, the low budget towpig ('99 C2500 Suburban 5,7L/4L80E/SF "14B"/3.73/HydroBoost) has met with it's first hurdle...

Shortly after doing a test drive & thunking down $$ on it, I stopped at I-40 & 540 to put some fuel in it. Needless to say, the $30 I put in didn't do much in the 44 gal tank :lol:

Drove it back to GSO (spent the night) & notice a small "wet spot" in Taters driveway the following AM. Over the next couple weeks, I noticed that there wasn't a real pattern to the drip, but hoped it was a return line, leaky fitting, or something quick/cheap/easy to fix...

Dropped the tank this evening and my suspicions were confirmed... the POs had dropped the tank (44gal = 30"w X 36"l X 15"ish deep) down on something, caving the center in a few inches & putting a small buckle & crack in the rear of the tank just 3"-4" up from the bottom (below the seam) :rolleyes: Outside of the tiny crack, the tank is in VERY good shape (NO rust, crud, or other bad juju)


Based on it's location and NOT wanting to drop it again, what's the consensus on repair?...

1) Give some type of putty/epoxy a shot

2) Have it welded/brazed/soldered (not sure if my local rad/tank shop still does this)

3) Blow $300 on a new tank (1/6 the value of the rig itself) :shaking:


:lol::beer:
 
junk yard... or drop the coin on a new one.. fuel system isn't the place to cut corners. Especially on your tow pig.. I'd slob a new pump in too while its out. Or at least cut a hole in the floor so its a quick fix if(when) needed..
 
Get the pump/tank combo and be done with it. Eliminate any other potential "suprises." It's still a smokin' deal. Call me a puss, but I wouldn't weld it myself.
 
Thanks brother!

yager said:
junk yard... or drop the coin on a new one.. fuel system isn't the place to cut corners.
Click to expand...

Why this over having having the crack (forgot to mention it's all of 1/4" long) brazed/welded?


yager said:
I'd slob a new pump in too while its out. Or at least cut a hole in the floor so its a quick fix if(when) needed..
Click to expand...

Well, I would normally, but there appears to be zilch wrong with the current in-tank pump (pending pressure test) and they're $300 :D

In complete honesty, it took 10 minutes to drop the tank (pull 2 clamps & hoses @ filler & vent, pull 2 bolts, drop tank, disconnect 1 electrical pug, 1 vent line, and supply & return lines)... would probably take 25 using a Leatherman, SO... I'll likely retain the current pump :(
 
Is this diesel or gas? I'll weld it if it's diesel.
 
I have used the fuel tank repair stuff in the past with good results. So I give thet a try.
I agree with Yager on the hole in the floor. I cut a hole in my sub. Almost empty in the shop the tank isnt very hard to drop. Dropping the tank on the side of the road with it 3/4 full is a whole different deal. The fuel pump may be available with out the pick up and sender. When I replaced my pump I bought just the pump for around $100 ( AC Delco pump)
 
Your Hot Dog Guy! said:
Is this diesel or gas? I'll weld it if it's diesel.
Click to expand...

Thanks Terry... It's gas, otherwise I'd weld it!

Got on the horn this AM to a couple a couple guys (full-time automotive wrenchs) and one suggested having King Radiator braze the crack. They're not open today, but do list gas tank repair on their website... will give them a yell on Monday to see if they feel comfortable trying that.


lugnut said:
I agree with Yager on the hole in the floor. I cut a hole in my sub.
Click to expand...

I may give that a shot this week. How large a hole did you cut?
Thinking I could rough it out with a jigsaw, weld a flange around the slug to hold it in place, secure it with a couple sheetmetal screws, seal it all up (neoprene? RTV?) and drop the cargo padding/vinyl mat back over it when done?

lugnut said:
The fuel pump may be available with out the pick up and sender. When I replaced my pump I bought just the pump for around $100 ( AC Delco pump)
Click to expand...

*IF* the tank is both repairable & not ridiculous $$, I'd like to go that route. I checked to see if Yo'reilly offered just the pump and it wasn't listed... NAPA? Stealership only?
 
There is a fuel tank repair epoxy available at most auto stores, it's on the isle with the rtv, gasket sealer etc. I've used it in the past, IT WORKS FANTASTIC. I'd drop the tank, flip it over, and use this stuff. OR, run it almost empty, and park on a hill so that no fuel would be near the crack, and repair it that way. A wire brush, and a few minutes to let the epoxy cure and the problem is solved.
 
I have welded more than one tank. Take it out - rinse with water and weld it with constant air pressure going in the tank. The flow of air in and out will keep it safe. Make sure to pull the sending unit out also. After you weld it rinse again and reinstall.

If there's any rust - replace it.

BTW - just for run I tried to blow one up. With the sender out and the fill hose off all I could get was a little flash. No real boom even with gas in it.
 
GubNi said:
I have welded more than one tank. Take it out - rinse with water and weld it with constant air pressure going in the tank. The flow of air in and out will keep it safe. Make sure to pull the sending unit out also. After you weld it rinse again and reinstall.
If there's any rust - replace it.
BTW - just for run I tried to blow one up. With the sender out and the fill hose off all I could get was a little flash. No real boom even with gas in it.
Click to expand...

It's the vapors that get you. A friend of mine rinsed one, let it dry for a couple of days, then put a match on a stick and held it over the sender hole. It got a good "whoomp" and popped the tank a couple inches off the ground. Back-purging isn't a bad idea, but I'd use CO2 or argon, as introducing MORE oxygen to the equation might not be the best idea. I can see where that would work, though, and I might be tempted to try welding it in that situation. However, the same friend that got the "whoomp" ended up using an epoxy and had great luck. It was a two-part putty stick. You know, the kind that looks like a giant "Cow Tail" candy. (I know Dave will pick up on an old-person candy reference! :flipoff2:)

And by the way, I know somebody personally who lost their father to welding not on, but over a gas tank in a car.
 
Caver Dave said:
Any idea which of the dozen or so it was? Maybe this offering from Permatex?
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That looks like the right stuff. It should come with a little applicator brush, and a mesh screen that can be imbedded into the epoxy over the crack.

To me, welding on a gas tank just isn't worth the risk.
 
Caver Dave said:
I may give that a shot this week. How large a hole did you cut?
Thinking I could rough it out with a jigsaw, weld a flange around the slug to hold it in place, secure it with a couple sheetmetal screws, seal it all up (neoprene? RTV?) and drop the cargo padding/vinyl mat back over it when done?




*IF* the tank is both repairable & not ridiculous $$, I'd like to go that route. I checked to see if Yo'reilly offered just the pump and it wasn't listed... NAPA? Stealership only?
Click to expand...

The hole I cut is about 10inx10in. I did it just like your thinking and sealed it with RTV. With the carpet down you would never know its there.

I got my pump from NAPA
 
I'm a fabricator so that's the route I would take, however MarineTex (spelling questionable) is a very good two part epox. that I have had good results with on several plastic tanks for gas. The only place I have found it is at Marine supply houses. It also says specified for gasoline applications on the product label.
 
Was leaning towards the epoxy... until I spoke with Doug @ King Radiator! He said they'd take care of it for about $50 (soap/water cleanup, since boiling it out would remove the galv. coating, prep, & silver solder) = cheap insurance an epoxy patch won't fall out/leak down the road!

Still gonna add the pump access to the backend before it all goes back in though! :lol:
 
catfishblues said:
It's the vapors that get you. A friend of mine rinsed one, let it dry for a couple of days, then put a match on a stick and held it over the sender hole.
Click to expand...


I've been told that filling the tank most of the way with water (after a good wash/rinse) before welding cuts down on the room for the vapors to expand and also absorbs a lot of the energy from any combustion that does occur.


I've never done one myself, but I think if it was being purged and mostly full of water you'd be pretty hard pressed to cause a dangerous explosion.

I used that permatex brand stuff a year or two ago for a motorcycle fuel tank. Held up for several months then started leaking again. In retrospect, I think I should have welded it but ended up selling the bike.

To be fair, I'd probably think harder about doing a 44 gal burban tank than a little 2 gallon honda tank.
 
Caver,

Ole Blue (or the USS Bounty as you called it) had a split at the filler neck on the tank. I cleaned it and mashed some Steel Putty from the Parts store into it and it never leaked again. and yes, this was a long time before I parked it. Back when I was DD'in it. if your spot is 1/4" long, I'd be tempted to putty the hole and keep truckin'
 
Archdukeferdinand said:
I've been told that filling the tank most of the way with water (after a good wash/rinse) before welding cuts down on the room for the vapors to expand and also absorbs a lot of the energy from any combustion that does occur.
Click to expand...

Doug indicated they used a "chemical" AFTER repeated washings (soap & water ONLY) to nullify any residual fumes and another chemical (alcohol?) to "dry" the tank before silver soldering... which doesn't exactly require sparks/open flames to do correctly!

Archdukeferdinand said:
I used that permatex brand stuff a year or two ago for a motorcycle fuel tank. Held up for several months then started leaking again. In retrospect, I think I should have welded it but ended up selling the bike.
To be fair, I'd probably think harder about doing a 44 gal burban tank than a little 2 gallon honda tank.
Click to expand...

My thoughts exactly!
While the epoxy could hold forever, (my luck dictates) it'd start leaking within months (minutes) :rolleyes:... given 250+ pounds of fuel sloshing, possibly causing tank movement, deformity, &/or stress on the patched spot... the solder patch appears to be the best option right now! :lol:
 
Update #1

Picked up the tank this AM from Doug/King Radiator.

He ended up cutting the crack ("sliced" inline with cutoff) to offer better filling. Brazed patch isn't "visually appealing", but does appear to be beefy enough to thwart future issues.

The big surprise was it ended up being LESS than quoted!

Earlier this week, I cut a 10" round hole in the 'Burb (center above the pump) and have been working on the "slug"... cutting/welding tabs to it to hold it up/secure it.

Pics at Eleven...
 
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