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Question for the serious car restoration guys - rusty gas tank 1931 Model A

Waorani

Crusty Caballero
Full Member
Minuteman
Feb 14, 2017
2,941
4,383
Greenbow, AL
Given the depth of knowledge of folks here, I thought I would put this out for any suggestions, tips, etc. Friend agreed to help another friend's estate get a 1931 Model A running so it can be sold. Initially thought simple enough but as usual gas was left in tank (now evaporated) who knows how many years ago and tank is rusted but not obvious if any leaks. Now the hard part. Tank is also the cowl between hood and windshield so it's painted and part of body. And on top of that, apparently late 31s had fuel outlet in different place than previous and the model ended in 31 so very limited and unobtanium. So even if a correct tank can be found or earlier made to work, then comes tearing into the body and trying to match paint. All of which is turning into a major project for someone just trying to help out his friend's estate.

I know there's various products for cleaning/treating/sealing gas tanks but anyone familiar with any products/chemicals or processes which can be used to clean a tank like this in place? Volume is 11-12 gal and filling/draining should be doable. No one is trying to hide anything from potential buyers, just trying get it back into minimal running condition vs selling as is. And yes I know there are a zillion car forums out there.

IMG_1293.jpg
 
Go to mac’s model a parts and buy a new one. Even though fitting is a nightmare.

The Bill Hirsch and similar products simply don’t work. You can’t get a tank clean enough to get sealant to stick. It’s an industrial process to clean a tank enough to get any of those coatings to work.

I send my tanks up to Canada. But it’s not worth it for model A and T and modern cars because the tanks simply are easier to buy as reproductions..

Sirhr
 
As @sirhrmechanic stated a repro is better. I tried using the tank cleaner and sealer on a original 69 corvette tank and it was a waste of time and money. Ended up just getting a new reproduction.
 
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Thanks. Not seeing any Model A tanks at Mac's and installing rear tank would be last resort. We looked at a locally available tank yesterday but it's earlier so outlet is in wrong place and steering wheel support is broken off. Can be made to work but then there's still fitting/painting to match.

I didn't think there was a simple fix but figured worth asking. I've also tried to talk him into just telling estate it needs major work and they need to adjust their expectations and sell as is. But he's got history with the family, want's to help, and I think is a little worried it will be seen as attempt to devalue so someone can get a deal.

I've always heard the DIY cleaning/sealing fixes don't work but have never tried. The few tank issues I've dealt with either weren't in bad condition and cleaned up easily or were simply replaced.
 
There are some state of the art radiator shops that will cut a window in the tank, sandblast the entire inside, weld the window closed and then coat the inside of the tank....
 
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I've used Evapo-Rust for a lot of stuff and thought about it for this project. It works and might be an option just to break down crud and flush out. $200 or so to fill tank but it might have some life left afterwards. Still would be a sketchy tank but at least might allow it to get running w/ consideration of making known to prospective buyers. If the damn thing wasn't also the front cowl/dashboard and integral part of the body it wouldn't be such an issue.
 
Again, plenty of fuel system parts but no tanks that I can see. I don't know if there are any repop tanks given the liability of a gas tank that sits above the driver/passenger legs and isn't that part of why they were moved to the rear in '32?
 

Seems to be for your specific year. Backorder though.
 
I've used Evapo-Rust for a lot of stuff and thought about it for this project. It works and might be an option just to break down crud and flush out. $200 or so to fill tank but it might have some life left afterwards. Still would be a sketchy tank but at least might allow it to get running w/ consideration of making known to prospective buyers. If the damn thing wasn't also the front cowl/dashboard and integral part of the body it wouldn't be such an issue.

Only need a bottle of it, some chain, and your nearest washboard dirt road.


Since it has to stay nice, I'd drop some cleaner in with a chunk of chain and strap it down securely in the bed of a truck. Drive around and run errands for a few days. You'll be amazed the stuff that pours out.


We used diesel and a gravel road, but we were very unconcerned about scratches and dents.
 
I call all the radiator shops in your area, or hit up the local cruise-ins and show-n-shines and ask the folks with old packards, studes, oaklands, etc where they got theirs done. Out of 5, at least 2 should know. The others are just posers who bought the restored car as is and who only know money.
There are some other specialty tank shops as well, but you may be surprised what is around locally. We had a 47 willys we had a radiator shop put an original filler neck on a narrowed chevy s10 tank that was the right dimensions to also fit the 4.3L vortec, and dual exhaust.
 
Risk versus Reward ? Like Paul Harvey used to say "And now, the rest of the story".... As the story unfolded here it sounds like your best option is to sell it as is, just as it sits....
 
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Seems to be for your specific year. Backorder though.
Thanks but that's to relocate tank to running boards. Might be an option for future owner.
 
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I call all the radiator shops in your area, or hit up the local cruise-ins and show-n-shines and ask the folks with old packards, studes, oaklands, etc where they got theirs done. Out of 5, at least 2 should know. The others are just posers who bought the restored car as is and who only know money.
There are some other specialty tank shops as well, but you may be surprised what is around locally. We had a 47 willys we had a radiator shop put an original filler neck on a narrowed chevy s10 tank that was the right dimensions to also fit the 4.3L vortec, and dual exhaust.
Friend doing the work is the local old car guru and knows everyone in the area. None have solution which is part of why I'm trying to convince him to apologize to family and step back.
 
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Some radiator shops will boil and seal but like everyone is saying it’s best to buy new if you can
 
I would try to see if I can do a pressure test or a vacuum test of the tank. Number 1 priority would be if there are any leaks imo, pressure and a water tank will reveal the leaks. If there are leaks you could potentially look at brazing or welding where the leaks are (I suggest filling the tank with water prior to welding to prevent any potential fuel vapor ignition). Another option is to (I hate writing this) JB weld the leaks. Purging the tank of rust will be a PITA, but do-able. You can do something like what was mentioned above to clean/flush and then use a bunch of fuel filters.
 
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Thanks for all the replies. If it were mine and I was keeping, I'd probably change to 32 rear mount tank as suggested. I didn't think there was an easy, in-place fix but figured worth asking. If car was in the middle of build/restoration, sure pull the tank and better options then exist. But given current circumstances, that's beyond what's doable. I'm not sure from some of the responses all understand this is not simply a tank stuck between frame rails than can be easily removed/replaced.

1931-ford-model-a.jpg
A-dash.jpg
 
Thanks for all the replies. If it were mine and I was keeping, I'd probably change to 32 rear mount tank as suggested. I didn't think there was an easy, in-place fix but figured worth asking. If car was in the middle of build/restoration, sure pull the tank and better options then exist. But given current circumstances, that's beyond what's doable. I'm not sure from some of the responses all understand this is not simply a tank stuck between frame rails than can be easily removed/replaced.

View attachment 7778748View attachment 7778749
Other option is just rinse the tank with fuel. Then put an inline fuel filter and hopefully it doesn't leak and run it. Don't forget lead fuel additive.
 
Not knowing old cars why do you need a lead fuel additive?
Older cars didn't have hardened valve seats. Lead was in the old fuel that we used back in the day and it helped to provide some lubrication value to the valves. When we switched to unleaded fuel we lost that lubricating property (like diesels with ultra-low sulfur diesel which was the factor that destroyed many CP4 pumps and wiped out their fuel systems).
 
Coincidentally, I saw another Model A a couple days ago that's also likely coming up for sale. Owner old, feeble and probably hasn't touched it in years. Pink of all colors with mauve trim and peach wheels! Sounds terrible but it actually looked great.
 
Older cars didn't have hardened valve seats. Lead was in the old fuel that we used back in the day and it helped to provide some lubrication value to the valves. When we switched to unleaded fuel we lost that lubricating property (like diesels with ultra-low sulfur diesel which was the factor that destroyed many CP4 pumps and wiped out their fuel systems).

Cp4 pumps are a result of incompatible fuels. They were designed for euro-spec diesel, and ours isn't nearly as stringent on particle count and size.
Good filters that will actually do 1 micron will keep them alive for the life of the truck.
 
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I also have an A Model 31 Ford handed down through the generations.
Mine is completly stock other than it is running on a Wico mag but the original ign. parts are in the trunk. It damned sure shows it's age.
I used to drive it on occasion but the fuel valve coming out of the tank was faulty and leaked and would drain the tank onto the floorboards and cause a big stink so it has been in the garage for 40+ years. I think that was a blessing looking at your problems. My tank is clean and drained.

Looking at the pictures posted I think I see B Model wheels, and mine has them too. Special order from the dealership in Yuma Colorado along with a B Model, long since wrecked, so they only dealt with 1 wheel and tire size.

I have enough parts, engines, trans etc to build 2 cars and have been asked over the years to sell them but I have always held out that I wanted them to go to someone who retores and not turn them into a "Hot Rod" so it is still in the garage. FM
 
Cp4 pumps are a result of incompatible fuels. They were designed for euro-spec diesel, and ours isn't nearly as stringent on particle count and size.
Good filters that will actually do 1 micron will keep them alive for the life of the truck.
Majority of the failures are claimed to be the result of lost lubricity post diesel fuel change.

From the class action:
"Why Does it Fail?
The problem with the Bosch CP4 pump, according to a recent fuel pump class action lawsuit, has to do with the sulfur content of diesel fuel made at U.S. refineries. U.S. environmental regulations limit the amount of sulfur allowed in diesel intended for the domestic market. This affects how well the moving parts of the pump are lubricated. These pumps were originally designed in the 1990s for the European market, where the permitted sulfur content of diesel fuel is higher.
How Does This Cause Engine Damage?
Because of its lower sulfur content, U.S. diesel fuel does not provide adequate lubrication for the Bosch C4 components. As a result, the mechanism sheds small bits of metal, which are then released into the fuel system. As these make their way to the fuel injectors and the cylinders, they essentially “gum up the works,” eventually causing catastrophic engine damage."
 
I think that's where this is headed.
For the sale of the car, it's a great honest way to do so. Let the future owner make the decision, being how the tank is also the body of the car.

Let existing tank totally dry out, let the rust want to flake off because it is so dry, then, put a piece of wood, press it to the outside of tank where rust is on the inside. Take a quarter sander and press the meat of a part of the plastic housing of the sander, to the wood, to the tank.
You should gently vibrate the fuck out of the inside rusty tank.

Drink a fucking beer.

Vacuum and clean up and put an inline filter on it like the guys said above.

You have a running car, which someone can temporarily enjoy while they make their fuel tank, investment decision
 
I didn't know that the Pinto engineer's had such an early start. Interesting thread. I'll assume that there's no way of installing a bladder inside the tank?
 
Older cars didn't have hardened valve seats. Lead was in the old fuel that we used back in the day and it helped to provide some lubrication value to the valves. When we switched to unleaded fuel we lost that lubricating property (like diesels with ultra-low sulfur diesel which was the factor that destroyed many CP4 pumps and wiped out their fuel systems).
You don't need Lead additive in a model A... tetraethyl lead didn't really come in until the later '30s and while, yes, you will get some valve seat recession on an A or a T... it is irrelevant in terms of how many miles the cars are typically driven.

What you DO need to make sure... is that if you have a flat tappet engine, you use a Zinc ZDDP additive... which has been removed from a lot of oil.

Cheers,

Sirhr
 
Given the depth of knowledge of folks here, I thought I would put this out for any suggestions, tips, etc. Friend agreed to help another friend's estate get a 1931 Model A running so it can be sold. Initially thought simple enough but as usual gas was left in tank (now evaporated) who knows how many years ago and tank is rusted but not obvious if any leaks. Now the hard part. Tank is also the cowl between hood and windshield so it's painted and part of body. And on top of that, apparently late 31s had fuel outlet in different place than previous and the model ended in 31 so very limited and unobtanium. So even if a correct tank can be found or earlier made to work, then comes tearing into the body and trying to match paint. All of which is turning into a major project for someone just trying to help out his friend's estate.

I know there's various products for cleaning/treating/sealing gas tanks but anyone familiar with any products/chemicals or processes which can be used to clean a tank like this in place? Volume is 11-12 gal and filling/draining should be doable. No one is trying to hide anything from potential buyers, just trying get it back into minimal running condition vs selling as is. And yes I know there are a zillion car forums out there.

View attachment 7778255
By the way... PRETTY car and those roadsters are bringing some good money compared to a lot of the other styles. Now if it was a '32 Coupe... that would be solid gold! But that's a very desireable and pretty body style. Not many originals left, either. So many got chopped and 'rodded!

Sirhr
 
An update and unexpected twist. Multiple flushes of the tank have yielded a seemingly unending stream of goo and loose rust. So far no leaks but we rigged a small under-hood tank just for testing and it runs great. Friend working on it told family he's done all he can and needs the space so I offered to let them store at my place until it could be sold. In the meantime they've had a few tire kickers and low-ball offers but hadn't seriously tried to sell it. I've never expressed anything other than a casual interest in it but out of the blue today it was offered to me for a too good to pass up price so I bought it!

Other than continuing on the tank (or going to a new rear mount tank) those lime green wheels have got to go!
 
1-You don't need any additive, that whole hardened valve seat bullshit was proven bunk in the 70's
Do you honestly think older vehicles had soft valve seats ?
That wouldn't work for very long would it ?

Remove the tank, it's really not that hard to do, I could have it on the ground in an hour.
Get about 15-20 small rocks about 3/4 to 1 inch....count them, put them in the tank and put the lid on.
Strap tank to tractor tire, put tractor on jack strands and run it in gear at idle rotating the tank.
Leave run for about an hour.
Remove rocks, counting them again to make sure none stay behind.
Reinstall tank and go on about life.
 
An update and unexpected twist. Multiple flushes of the tank have yielded a seemingly unending stream of goo and loose rust. So far no leaks but we rigged a small under-hood tank just for testing and it runs great. Friend working on it told family he's done all he can and needs the space so I offered to let them store at my place until it could be sold. In the meantime they've had a few tire kickers and low-ball offers but hadn't seriously tried to sell it. I've never expressed anything other than a casual interest in it but out of the blue today it was offered to me for a too good to pass up price so I bought it!

Other than continuing on the tank (or going to a new rear mount tank) those lime green wheels have got to go!
Congrats! As to the wheels unless hotrodding it keep them, are a nice original accent.
 
Head to Autozone. Give them the year, make, model and last eight of the VIN and order a new one. They may even have it in stock.
 
I was a painter at a high end shop back in the day. On motorcycle tanks I used acid to etch the tank. Once it was dry there is a 2 part epoxy you mix to seal the tank. It coats the whole tank in clear resin I just did this on my generator recently. Its a low cost option that works well.
 
In its new home! I didn't realize the friend working on it had pulled the small tank we rigged and hooked the original tank back up. We put a couple gallons of gas in and so far, so good. No leaks and no rust settling out in the sediment bowl. We'll see how it goes from here.

Just what I needed - another project/money pit. If anyone knows where there's a set of original Landau irons I'm in the market!

31 Model A.jpg
 
Look up these guys.


They have a ton of Model A stuff, including knowledge.
 
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Look up these guys.


They have a ton of Model A stuff, including knowledge.
Yep, found them last night along with MAC's mentioned above and Mike's. Friend likes Snyder's Antique Auto Parts and has used them for years. A new learning experience.
 
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I used to work on them and build them all the time when I was a young man. We used to deal with Bert’s back in the 80’s.
 
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Now that it's yours can pep it up a bit:



OK, a restored carb is probably a bit much, but can still do some cool stuff to it.
 
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Congeats Sir! Just remember, you are the caretaker of other folks memories. My car is an ambassador to me. I've heard stories, met people, and had experiences I'd have never had without my old rigs.
And now, those memories get a new chapter with you to pass on it all that came before you.

Ps. Yes. Those lime greens have got to have a trip to the media blasters and a recoat.
 
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