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Discussion Starter · #1 ·
For awhile my brother's 74 has been leaking fuel out by the gas tank. I thought it was a dry rotted hose but turns out a section on the drivers side looks like someone peppered it with a shotgun and when I went to take down the spare tire carrier fuel came rushing out onto me:surprised The sending unit ground strap is broken to so now we're getting a new tank and sending unit. The rust in the tank is unsightly as it's been sitting dry for 10+ years and moisture has taken it's toll. With the tire carrier, both wheels, and both mufflers out of the way I'm starting on the rear suspension:D That's all for now:thumbsup:
 

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hope you took a shower right afterward. My hands always get dry and chapped after any appreciable contact with gasoline.

Sounds like a good project :thumbsup:
 

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Discussion Starter · #3 ·
I did. Is the POR15 worth it as I've never repaired one? It doesn't have huge holes just a bunch of pinholes. It will be fun as this will be my first Corvette tank R&R.
 

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I did. Is the POR15 worth it as I've never repaired one? It doesn't have huge holes just a bunch of pinholes. It will be fun as this will be my first Corvette tank R&R.
Those small holes are most likely rust holes. If they are rust holes, the whole bottom of the tank is thin as paper. I`d recommend you to swap it for a new one (not a used one, they might be just as rusty on the inside). My tank had a very small rust hole, but it turned out the bottom was completely rotten. The hole didn`t even look like a rust hole.
 

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:agree:

When it comes to tank integrity, don't skimp. Those pinholes indicate materiel thickness. All the rust inside the tank is what's left of the tank, layer by layer.

Remove it, source a used one, prep it, install with new strap, reinforced rubber lines, and while you have it out you can perform any frame prep work that's hard to get to while the tank is installed.
 

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Discussion Starter · #6 ·
I agree with all of you on replacing the tank but my brother wants to "save" it even though I told him that it is pointless cause of the large chunks of rust. I forgot to mention I have the tank already out. I'll take some pics today. Everything else tank related was in great condition. The tank, sending unit, and hoses are getting replaced though and everything else gets a clean-up and paint.
 

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Yeah please don't let your brother re-use that tank. :thumbsup:
 

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Discussion Starter · #8 ·
I talked him into getting a new one based on y'alls advice and mine:thumbsup: Brakes and suspension will come first then the tank. I'll try to get the pics on tonight if I don't get busy or forget:laughing:
 

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This is where the fuel dripped onto from my tank. Mere luck prevented my car from catching fire. That`s why I recommend him to change the tank. And don`t buy a used tank unless you have inspected it personally, they might have just as much rust. I don`t know if the 74 tanks have the rubber bladder inside, but if they do, DON`T buy a used tank. Condensate (right word?? water vapour) collects on the outside of the bladder and ends up lying between the bladder and the metal in the bottom of the tank. Recipe for disaster. Tell him the car won`t lose any value (that is if it is the original tank with the build sheet) if he replaces the tank, but keeping that deathtrap will only hurt the cars value.




This is what the tank looked like. We inspected it and found no holes or damages and had planned to install it after we sandblasted and painted the frame. We put on a piece of cardboard so as to not damage it and left it there for 3-4 days. Then we moved the tank to make room for me to sandblast the frame and we found the cardboard to be soaking wet with gasoline. We looked again for holes, but found none. Then my father took a screwdriver and drove it trough the bottom of the tank without actually trying. The whole damn thing was completely rotten. I took what was left of the build sheet and dumped the rest.

EDIT: I`m glad you managed to convince your brother. I started writing this before those two previous replies were posted and didn`t see them until I had posted myself.
 

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Discussion Starter · #10 ·
Ours was leaking on the mufflers to. His mufflers had big holes in them so the gas was leaking in the mufflers.
 

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'71 Gas tank replace

I've got a '71 t-top small block that sits a lot now. Developed leak in gas tank on drivers side. Dropping roight onto top of muffler. Anyone have more pics of replacing tank, not as part of body off restoration? Looks like I'm facing large bill if I have to farm it out, and money is tight right now. Any suggestions? I can buy a new tank for around $200 from Vette mail order shops. Just wondering what labor would cost me if I had someone do it.
 

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I've got a '71 t-top small block that sits a lot now. Developed leak in gas tank on drivers side. Dropping roight onto top of muffler. Anyone have more pics of replacing tank, not as part of body off restoration? Looks like I'm facing large bill if I have to farm it out, and money is tight right now. Any suggestions? I can buy a new tank for around $200 from Vette mail order shops. Just wondering what labor would cost me if I had someone do it.
I posted some pics here that may help you decide to tackle the job yourself. Not noted in pics is the removal of the spare and mufflers.

http://forums.corvetteforum.com/1575833029-post4.html
 

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I've got a '71 t-top small block that sits a lot now. Developed leak in gas tank on drivers side. Dropping roight onto top of muffler. Anyone have more pics of replacing tank, not as part of body off restoration? Looks like I'm facing large bill if I have to farm it out, and money is tight right now. Any suggestions? I can buy a new tank for around $200 from Vette mail order shops. Just wondering what labor would cost me if I had someone do it.

Don't waste your money, do it yourself! It's really simple, especially if you're replacing with new, (harder if you're refinishing the tank, like I did, and don't want to scratch the paint during install):

Also, during install, I recommend upgrading the OEM "anti-squeak" pads (which are really strips of tar based roofing paper...REALLY!.....don't buy them from anybody!) with rubber garage door weatherstripping (the kind that seals the bottom of the door) I got at Lowes.

 

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Discussion Starter · #14 ·
Thanks for the info on "anti-squeak" pads Metalkid:thumbsup: Hopefully next week my brother will have the new gas tank ready to install.
 

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Good Job selecting the new tank option.

You might consider that the same condensation that wiped out the tank, may also be in the fuel line(s). A good flushing will usually reveal the rust particles that tells you there is a problem. Run the liquid at the other end through a paint strainer to see if rust particles are present.

You mentioned POR15, great stuff for surface rust. It will plug pin holes in metal floor boards. I would not recommend use in a fuel tank.

Good luck, great project.
 

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You might consider that the same condensation that wiped out the tank, may also be in the fuel line(s). A good flushing will usually reveal the rust particles that tells you there is a problem. Run the liquid at the other end through a paint strainer to see if rust particles are present.

You mentioned POR15, great stuff for surface rust. It will plug pin holes in metal floor boards. I would not recommend use in a fuel tank.

Good luck, great project.
POR-15 makes a fuel tank sealer too. :cheers:
 

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Dropping and replacing a tank is pretty easy. I just replaced my 70 tank in a few hours.

This is how the 70 goes,

1. Syphon tank
2. Remove fuel filler lid.
3. Remove rubber gasket & fuel filler neck.
4. Remove exhaust/mufflers.
5. Remove spare tire carrier.
6. Disconnect fuel/electrical lines from sender unit.
7. Disconnect fuel/vapor return hose on side of tank.
8. Remove bolts from the two fuel tank straps (aft side)
9. Remove crossmember under fuel tank.
10. Pull/tip the front side of the fuel tank forward/down.

Your done.
 

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Have you bought the new tank already? If not, Tanks, Inc. has a nice inexpensive option for a non-NCRS type. I see they've gone up (I bought 1.5 years ago from them for $120), but I still think they are one of the best values.
 

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Too bad you don't have a 77. I've got a brand new in the box tank from Eckler's in my shop. Don't need it. Would make someone a good deal if they would get it out of there for me.
 
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