Fuel tank leak discovered.

[TheGreenCoyote]

So as I was underneath working on my '73 I saw what appeared to be a large damp spot underneath the fuel tank. The tank is on the right and I think it is a 20 gallon? As I lightly pressed the spot with my finger it started saturating the surface like crazy with gas. It is weird because the surface does not look damaged or rusty. The tank does not appear rusty at all. Is the tank just that thin now? I think I've been losing lots of fuel by the slow drip, drip drippin' away down there.

I am more than disappointed with the discovery because I only put the "new"bed on a few months back. I assume it would have been lots easier removing the tank without the bed on.

Is the tank relatively easy to remove with the bed on?

Does anyone here have experience removing the tank and repairing with one of those repair kits?

Any help is much appreciated. Thanks for all the help with my project so far. I am really enjoying being a new member of this site!

[cableguy0]

yea its pretty easy to pull out. the lines can be a bit of a pain but the easiest thing to do is disconnect the rubber lines on the truck side instead of the tank side. theres 8 bolts on the back side of the frame that hold the strap brackets on. its easiest to pull those bolts instead of trying to fight with the straps and just pull it out as an assembly. the repair kits only work ok on pin holes and in my experience you end up finding more and leaks as you plug em. the tank probably rotted from the inside out. im willing to bet theres other spots just as bad. a new tank can be had for about 120 bucks or less

[watahyahknow]

i've heared about rare gastanks (that aren't replaceable ) to be coated inside to cure the leaking , not sure i think they did that in a radiatorshop

[6772fan]

Seems to be a trend with these leaking. I just replaced the drivers side tank on my 78 longbed. I bought a new one at Auto Zone for 93 bucks. It was a 20 gallon tank and I removed the 8 bolts from the frame to the tank and took it out as a unit. It's also a good idea to go ahead and replace the sending unit while it's out.
One trick I discovered was to block it up just enough for clearance to reach through and cut the rubber fuel lines, reaching from the outside, and did the same thing in reverse order when replacing it with new rubber fuel lines. The straps can be a bit of a pain to line back up, and it's critical they are in the correct position when it comes to installing the new tank because the 8 bolt holes must be on the money.
It's not all that difficult, just takes some time.

[TheGreenCoyote]

Thanks everyone for the help. I see a fuel tank replacement in LMC that I think I will order. I hope it fits right!

[old Rusty C10]

the trick doing it from underneath is to snug the tank in the strap/mount assembly then let loose on it a tad so that you can move it and line up the mounts with the holes on the frame then snug down the mounts and install the thing.. you want to put one bolt in so you can put the lines on then bolt it all up

[Mr79C10]

Dont mean to jump on this thread,,, but JUST found that my tank is also leaking..

So Im looking and found 16 & 20 gal tanks.
Rock Auto, less then a benny,

[KrazyRay]

My father-in-law had a hole in the tank of his 87 and I did a temporary fix by using black permatex and a pan head sheet metal screw. Its held for 1 1/2 years but I have begged him to replace it since. I even gave him the replacement tank.

[watahyahknow]

when you have a small leak down the road you can actually fix it temporary with a bar of soap (wish you offcourse have laying around in the truck at all times) just push smear a small piece in the hole , or oldfasioned (non chemical but from a rubbertree) chewinggum
i worked for a tire exaustchop and we did by accident drilled intoo the tank we sanded the surounding and a copper coin and used a realy big electric solderingiron to solder the coin over the hole , worked fine but it was a unrusted tank

[Mr79C10]

What is the material thats between the strap and tank?

[watahyahknow]

usually rubber or bitumen (use it in roofing)

[bitchin85]

Originally Posted by watahyahknow

usually rubber or bitumen (use it in roofing)

my tank was leaking too. but the stuff wasnt rubber it was almost like plastic lined yellow insulation

[nlped]

I got my replacement tank from Rock Auto. Their price was the best and it was shipped right to the house...nice!

It's not to bad to do as long as your truck isn't really low, and your working on your back, in a gravel driveway, and it's raining... Oh, I digress

[cableguy0]

its always raining when you gotta work in the driveway. and theres always that one spot that drips on ya when your under the truck no matter where you lay. i agree rockauto or advance auto parts is the best way to go. lmc doesnt deserve your money

[bitchin85]

when you buy a new tank, what do you coat it with so it wont rust? is there stuff specifically for gas tanks or frame paint or??? michigan withers are hell on steel.

[cableguy0]

well if ya figure the first one lasted close to between 20 and 30 years. i dont really think its worth worrying about. you could always paint it but tanks always seem from the inside out.

[boatpuller]

man,if i had the bed off like that,i'd look real hard at the blazer type conversion or do plastic between the rails in the rear.

[watahyahknow]

you might be able to have the tank zinq coated inside and out that should hold out for a loooooong time
and i noticed that the tanks catch a lot of dirt so some rubber mudflaps at strategic places might work as whell