rust in 29 coupe gas tank

[oldspert]

I have done a search and do not find the info on removing a gas tank from a 29 standard coupe. Does the tank come out from inside the car or from under the hood. I know to disconnect the speedometer and switch wires, the fuel shutoff, drop the steering column and the choke rod. Anything else?
There is lots of rust particles that I can remove with a siphon pump but the tank will have to be removed to clean it better.

[rotorwrench]

The tank comes out the front. The way the lower cowl panels are curved sort of blocks it in there. The hood and radiator steady rods all have to be removed then the bolts & clamps come off. A person may need to replace the welting too.

The tanks were pretty thick metal when new but ones with a lot of corrosion may have some thin spots. Light surface rust might be OK with a phosphoric-zink conversion soak but it can eat right through real thin spots. Cutting the top off and grit blasting is the best way to repair a tank but it's a complicated job to fix it and weld it back together. Sealing the tank it also complicated on the 28/29 tanks. The baffle in there in hard to get coated unless a person has a lot of sealer.

[oldspert]

Is the tank part of the cowl? You mentioned might have to replace some welting. Does the tank come out just below the windshield and the cowl stay in place or all of it come out as one piece?

[neds29]

The tank comes out below the windshield, which stays in place. For '28-'29's it's easy to remove; simply remove the fasteners, steering wheel clamp and fuel lines (the shut-off can remain) and connections to the instrument panel, the hood and supports. Make sure all of the fasteners are off. After all of that give it a slight push forward and depending on the amount of corrosion on your car, it should pop out.
There are several good videos on you-tube for cleaning the tank.
Ned

[Randy in ca]

Step Number 1 should be to disconnect the battery.

Here's a quick video of how the tank comes out after all the required stuff is disconnected and removed. Coupe body is done basically the same as the one shown.

Link to video: https://www.youtube.com/watch?v=lsI1jOm24wk

[Model A Ron]

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I know Paul Shinn has a good video about removing rust without cutting any holes in the tank once you get it out. I would not recommend putting any holes in the tank as you will live to regret it.

[oldspert]

Does anybody make a reproduction gas tank for these? Looks like there would be a real market for this item.

[Gary WA]

Originally Posted by oldspert

Does anybody make a reproduction gas tank for these? Looks like there would be a real market for this item.

No None to date

[Gary WA]

You could make a Dirty leg and run it for some time they work good>

[rotorwrench]

When I cut the top off, I follow the original seam where the roller seam welder originally mated the top to the bottom. Cutting holes in them would be worthless for cleaning and be almost impossible to close off without warping the metal.

These tanks were made of stamp formed parts. The upper firewall is a separate panel that is spot welded to the upper and lower tank halves. The thickness is close to 1/16th inch so the dies had to be pretty sturdy. There are three internal baffles panels, the lower conduit panel, and the instrument panel port for the fuel gauge all included along with the filter neck. A person can't forget the fuel outlet bung and the steering column support with internal reinforcement either. It would be very expensive to reproduce these tanks. The 30/31 tank doesn't have the firewall panel but it would still be expensive to reproduce. The top panels for the 28/29 types are the only panel that is reproduced but it has no filler neck and no place to put the hood lacing. They are made for the hot rudders that buy the Brookville reproduction bodies.

[BRENT in 10-uh-C]

Originally Posted by oldspert

Does anybody make a reproduction gas tank for these? Looks like there would be a real market for this item.

To answer your question, there really is not a need to reproduce these tanks when there are companies that restore original tanks at likely at half to one-third the price of what a a new tank would cost. Most people would never pay the $1,500.00 to $2,000.00 to purchase a new fuel tank.

FWIW, below is what your tank looks like when it has been opened up. We have been restoring these tanks for nearly two decades now. It is my opinion that unless you can open the tank to expose the corrosion and to be able to get to all areas to blast the tank totally clean, then you are wasting your time.




.

[oldspert]

Brent, when you weld the pieces back together, do you use TIG or MIG? I am professionally able to weld the parts back together with either method. Wasn't actually looking to split the tank, but from what you say I will do it.

[BRENT in 10-uh-C]

Originally Posted by oldspert

Brent, when you weld the pieces back together, do you use TIG or MIG? I am professionally able to weld the parts back together with either method. Wasn't actually looking to split the tank, but from what you say I will do it.

We use a TIG to prevent warpage, but I suppose if you were proficient enough, you could use a MIG. We have a jig to fixture the tank when tacking it back together. This is a must to keep the tank from being skewed during the re-assembly part. You do not want a warped tank when it goes back together into the cowl. The final thing to note is to make sure you have enough sealer to be able to submerge the baffles. Generally speaking you will need about 4 gallons of sealer on a 28/29 tank, and 4½ gallons on a 30/31 tank. If this is not done, you will have bare metal where the sealer did not reach during the coating process. When that happens, your rust problem was never solved after all that work.

[Brentwood Bob]

Thanks Brent, appreciate the pictures, and the knowledge.