Cleaning Internal Corrosion In Tank

[Jesse Bernal]

I have a problem with internal tank corrosion. I want to apply a sealant but I don't know what to do about cleaning the tank. Do I scrub it with a wire brush or do I have to sand it down. I haven't taken the tank off so I don't know how much room I have to put my arm in. Its an 82 fuel injected vette so the pump is in the Gas tank.

[Patrick H.]

Re: Cleaning Internal Corrosion In Tank

Jesse,

Overall, your absolute best bet is to purchase a new tank. I just checked the Quanta site, and they don't list them as being available, but you may be able to get one elsewhere (GM?).

Personally, I have used the coating kits as well as purchased new tanks. I vastly prefer buying a new tank if it is feasible. As Joe L mentioned in an earlier post, the tank is a safety-related item, and you don't want to tank chances if you don't have to.

To clean the tank, many of the kits come with an acid to etch the inner tank and remove the rust. My Eastwood kit of several years ago also included a 1 foot length of chain to drop into the tank and swish around in an effort to "scrub" the tank bottom. When I coated a tank last summer, I used the supplied acid, which removed a lot of the rusty scale, but some was still left. My arms are too big to reach inside with any ease, and my wife wasn't about to volunteer her time to sand the inside of a gas tank.

As the tank only had a very few pinholes in the bottom, and was otherwise in great shape, I elected to coat that one rather than replace it. I know, however, that the rust is still hidden within the tank wall, and that someday it will have to be replaced.

Hope this helps,

Patrick Hulst

[Joe L.]

Re: Cleaning Internal Corrosion In Tank

Jesse-----

I'm afraid that I have bad news for you. 1978 to 1982 Corvettes use a steel tank with a "rubber" bladder molded into the tank. This tank, GM #457999, was discontinued in 1994, at a then list price of over $425. As far as I know, it is not being currently reproduced in any form.If your tank is sufferring from internal corrosion, I would suspect that the bladder has seperated or cracked. Otherwise, the corrosion may just be limited to the other internal steel components of the tank/fuel pump/fuel pick-up/fuel tank sender system. But, I doubt it. The fuel pump and fuel tank sender assembly are fairly easy to remove on these cars, so you should be able to readily check these. The fuel pump is currently GM #25168719 and GM lists for $65.55. The sending unit is GM #25003153 and GM lists for $456.70.

1975-1977 Corvette owners are in even worse shape as far as fuel tanks go. Those cars used a steel tank with a seperate "rubber" bladder. The tank was GM #348366 and the bladder was GM #348378. Both have been discontinued for over 10 years and are extremely difficult to locate. The bladder GM listed for over $700 when it was discontinued.

As far as I know, no company currently reproduces any of these components. Also, since the bladders are ORGANIC material exposed to an ORGANIC solvent(gasoline), they are life-limited. Just what their life is, I don't know.

I have heard that someone was going to produce a steel-only version of these tanks. Such a "reproduction" would be practical, whereas a duplicate of the originals may be infeasible for tooling reasons. However, I strongly suspect that product liability concerns will affect the outcome of a decision on this one. The few large companies that currently produce steel gas tanks would have a lot to potentially lose and little to gain by marketing such a tank due to the relatively small size of the market.

[Duke W.]

Corvette Fuel System Saftey Issue

Long before exploding Pintos, there were exploding Corvettes. I first learned of this problem with C2/C3s when I was an engineer at Pontiac in 1968. Another engineer who worked with GM's lawyers told me about the problem. The fuel tank sits atop the frame and is very vulnerable in a rear collision. The fuel tank can burst and spill its contents into the cockpit. The night following my conversation with the other engineer, a '68 Corvette was rear ended in Detroit and burned. The first ever million dollar product liability award involved the fuel tank rupture of a '63 Corvette, and this case was taught at the Southwestern Law School in L.A. in the seventies. GM put the bladder in the fuel tank to address this issue, but I don't think most of us are aware of how vulnerable we are in a rear end collision. It's even worse today with all the trucks and stupid ugly vehicles (SUVs) running around that don't have to meet passenger car bumper height standards.

I would be willing to sacrifice originality to have a specifically designed "fuel cell" for my '63, but the aftermarket has never considered this, probably because most owners aren't aware of this serious saftety hazard. It's tough to even think that our beloved cars could have such a defect, but in the era it was designed there wasn't any active safety design, standards, or crash testing. I sometimes wonder if the designers ever thought about the fuel tank issue. When you really look at the layout, it doesn't take a whole lot of intuition to see the potential problem, Maybe if more people become aware of the Corvette fuel tank safety issue the aftermarket will come up with a solution, but I'm not betting on it.

Duke

[Patrick H.]

Re: Corvette Fuel System Saftey Issue

Duke,

I may be mistaken, but I believe that GM even moved the rear bulkhead forward, possibly in the 1972 MY, just for this reason. I believe the thought was that there would be more space for a crumple zone between the tank and the passenger compartment.

Anyone else know about this one?

Patrick

[Patrick H.]

That Bladder thing

Joe,

I remembered about the bladders AFTER I had hit the post button. Oh well. Thanks for the clarification. I figured that if someone was looking in and seeing corrosion of metal, there couldn't be much of a bladder...

Patrick