C3 Gas tank (with bladder) leak

[Kurt]

The gas tank in my 81 is leaking and since it has the bladder all the repair solutions that I have found do not apply. I have also investigated buying a new tank, but can't seem to find one.
I'd appreicate any advice on repairing or replacing the tank. Kurt

[Gary S.]

Re: C3 Gas tank (with bladder) leak

Maybe Paul Borowski will chime in here but he had a good gas tank, just a "bladder control" problem that he wrote about in The Restorer. He pulled the bladder out of his car and ran a straight steel fuel tank, just like the older C3's. I would suggest that you might be able to order a new tank from Quanta Products and just skip the bladder.

Gary

[Kurt]

Re: C3 Gas tank (with bladder) leak

I checked Quanta Products, but they only cover up to the '77 model. You mentioned an article in The Restorer, so I was wondering if you could tell me the best way to read that article.
Thanks - Kurt

[Joe L.]

Re: C3 Gas tank (with bladder) leak

Kurt-----

As I've mentioned several times previously, fuel tanks for 1978-82 Corvettes are going to be a big problem and headache for owners of those cars in the coming years. These model years use an fuel tank with an integral, polyethylene or polypropylene bladder. As far as I know, the integral bladder cannot be removed from the tank. Certainly, it can't be removed from the tank easily and I don't think that it can be removed through the sender/filler opening.

Although polyethylene or polypropylene is relatively impervious to gasoline, it's not completely impervious. Over time, and especially after exposure to some of the various compounds that are used to blend gasoline at different times of the year and in different regions, the bladder material will degrade.

If it is possible to remove the bladder as, hopefully, folks that have done it will comment on, the tank could be used "bladderless". That would compromise the safety of the tank, but I don't think that it would be any less safe than 53-74 Corvettes which never originally had bladders in their tanks.

There is currently no reproduction of the 78-82 fuel tank available. I believe that this has a lot to do with product liability considerations associated with such tanks. While the 75-77 tank is reproduced, the seperate bladder used with that tank is not reproduced and, I believe, for the same reason that the 78-82 tank is not reproduced. Folks can use the 75-77 tank without bladder but, in doing so, take the risks more-or-less at their own peril.

The configuration of the 78-82 tank is unique and designed to fit the configuration of the 78-82 rear deck. It is not possible to install a 75-77 tank or an earlier tank without considerable modification. Certainly, no "clean" installation would be possible. Also, except for the few 63-67 Corvettes produced with the N-03 big tank option, the 78-82 Corvettes have the largest fuel tank capacity (25 gallons) of any Corvette ever built from 1953 to the present.

[John L.]

Re: C3 Gas tank (with bladder) leak

Kurt,Joe
I thought that there have been several conversions to a bladderless tank by removing the bladder from the tank. Will not the tank act a similar tank as in a 77 and back? It will hold fuel without the bladder right?? I don't see how it would be any more of a problem than a earlier version unless it might have something to do with the vapor return or like.
Just my 2 cents. But I would like to hear others thoughts on this as I also own a 79 and I'm sure sometime in the future I will be encountering the same problem.
John

[Joe L.]

Re: C3 Gas tank (with bladder) leak

John------

The 75-77 tanks use a removable bladder. In this design, the steel fuel tank and the bladder are seperate pieces. The bladder can be and must be inserted into the tank. Likewise, it can be removed from the tank.

The 78-82 tanks use an INTEGRAL bladder. In this design, the tank is manufactured with the bladder in place. I believe that this bladder is much more rigid than the the 75-77 style removeable bladder and that's why, I believe, it would be much more difficult to remove from the tank. However, I've never actually tried this operation and I would defer to anyone that has tried it.

As far as I know, the steel tank used for 78-82 is fuel-tight even if the bladder is compromised. Indeed, providing "secondary containment" would be a primary function of the steel tank shell and if it were not in and of itself fuel-tight, it would not be able to serve this function.

[Paul B.]

Re: C3 Gas tank (with bladder) leak

Kurt, while there is currently "no new" tank on the market, there are MANY Corvette dismantlers out there that have these tanks by the dozens. Many out of wrecked, low mileage cars. At Bloomington & Corvettes@Carlisle swapmeets I see many nice ones everywhere. Check the DriveLine and also places like Contemporary Corvette, Michigan Corvette Recyclers, Tracy Performance just to name a few. These tanks are plentiful-they were by no means "rare". Every '78-'82 came with one, at least originally.