CSX 4000 Fuel Cell (Leaking)
 

Hello CC Community,

Looking for some advice here with a CSX cobra fuel tank leak. the leak is coming from the large oval plate that is secured with 12 bolts and allows for the pickup tube to pass through the plate and deliver fuel to the fuel pump. I have drained the tank 5 times and replace the gasket with 5 different types of gasket material

Nutrile Rubber 1/16
Nutrile and Cork 1/16 and 1/8
Permatex fuel resistant motoseal
Fiber 1/16

Everytime it leaks like 1 drop every hour. It's livable but I think the reason it's leaking is that there is not a clean flat surface that the oval plate mounts to. First question is do I have an aluminium tank or a stainless steel tank. I know if I remove the tank, the weight of the dry tank will be a good tell but once I know the material, I'm going to order a 1/4 inch aluminum or stainless plate, cut out an oval ring and pre drill to line up with the holes in the plate. Then weld the 1/4 ring onto the open hole in the tank ( I know to dry out the tank and rinse with water to remove all chance of vapor), but this way I would have a solid flat mounting surface to mount the gasket and plate back on the tank. It's a very sloppy opening in the tank and the upper section of the tank / oval hole has the tank folded edge overlay in the design so it's just not a great mating surface. Curious about he material (aluminum of SS) and has anyone else done this?

Ditch it. Someone here used to make an aluminum baffled tank. Search for it

Nick Acton perhaps?

That's him

Seriously. Soon if not already the foam inside will start to melt and clog your carb or injectors.. Just get a new one. You dont need the fuel cell.

Shelby told me the cell should be replaced after a ridiculously short time, like 5 years. If you've got a csx4000 numbered car its well past due

WARNING, Shelby 7000 & 8000 Series Continuation Cobra!!! - Club Cobra https://share.google/SO0KBOH2YW6Ky7PGz

Thanks for the feedback. the tank appears to be aluminum, and I've ordered 5/16 inch thick aluminum plate to weld a thick oval ring spacer to the oval cutout in the tank. The tank is fine and I don't plan on replacing it, I may however remove the foam and replace or just go without the foam. Once I remove the tank, I'll be in a better position to assess the health of the tank. I am also replacing the Facet brand electric fuel pump while I'm in there. These types of quality problems in construction are bothersome. The placement of the cutout in the tank is very close to the upper tank seam and extremely close to the bottom of the tank which has a rounded edge. This bottom section is where the lack of seal is causing leakage. Weather is still ice cold so now is the time to get er done. Thanks again.

I think Craig is supposed to make the best one.

Club Cobra - View Profile: cobrakiwi

Craig did my CSX4000. Easy to work with an prompt delivery :cool:

I could be wrong about this, but I was under the impression that a fuel cell is a "bladder" with "foam" inside that goes inside a "metal box". I don't know that the metal box holding the bladder is necessarily meant to hold the fuel in. I thought the bladder holds the fuel in.

So I am guessing that when you replace the "fuel cell", you are replacing both the bladder and foam?

So if you only replace or simply remove the "foam", could it be that the "bladder" is still the part that is leaking, which would not solve your problem if the metal box containing the bladder is not necessarily meant to hold the fuel in?

I think the "foam" acts to prevent the fuel from sloshing around the tank, so I think the idea of getting a baffled tank is that the baffles prevent the fuel from sloshing around the tank, which might be why some CSX4000 owners replace their setup with an aluminum baffled tank. If you do not take your car out on the track then the baffled tank might not matter.

It seems to me that Craig's customers give him nothing but glowing reviews of his work. I think Nick seems to have mixed reviews of his work.

The foam disintegrates first then the bladder will Crack.

You are correct about the purpose of the foam. Baffles will do the same without a shelf life. It doesn't matter much with a street car.

Pulling the foam out through the top port is like pulling a brick through you nose. The tank will be full if bits of foam. i suspect the bladder will collapse. Since it needs the foam to retain shape and be full of foam scraps.

If he doesnt replace the bladder it will eventually fail and we'll be right here again

The OP should contact shelby American or Hillbank for advice.


I eagerly await the results

I managed to solve my leak problem, the problem is that those 12 hex bolts have a tiny plastic washer, and because the plate is made of aluminum also, it forms micro dimples when you tighten the bolts using those tiny washers. I replaced the plastic washers with small stainless washers over 1 1/4 inch stainless steel fender washers. This allowed an even amount of pressure all around the gasket and now it’s sealed for good.

The problem is the rubber bladder. It has broken down over time. Sealing the bulkhead won't repair the problem. I tried that by sealing the bolts with Hylamar (sp). Worked as long as I didn't fill the tank above the bulkhead. Eventually, the tank began leaking out the lower left weep hole. One way to fix the leak was to replace the bladder, which is the route I took. We removed the tank and sent it to FUEL SAFE in Oregon (who made the unit) to be replaced. They will then make a new bladder for the tank install it and certify it for 5 years, then mail it back. The turnaround time is 8+ weeks. It is highly recommended that you replace all of your fuel lines and filters and flush out all of the fuel system because it has now been contaminated with the breakdown of the bladder and the foam. Plus, the fuel lines are more than likely breaking apart internally and hardening from age and the fuel contamination. How do I know all of this? I'm going through it right now. There may be less expensive ways to get around this, but I wanted to keep mine the way it came. The reason mine lasted so long (23-24 years) is because I have only used racing gasoline (112 octane) in the car. I have been told that it is better for the rubber etc. than 87 octane as well.

Craigs is a new aluminum tank . He adds baffle's . Nice job an quick to get it back. :3DSMILE: Back then Nick didn't have anything once I got a hold of him.