Leaking Fuel Cell Repair

Ron Earp

Admin
We've got a leaking fuel cell on our old Z SCCA car that is coming out in a couple of weeks. It carries a standard 15 gallon road race cell with "special" dual pickups. Just the bladder, not the entire cell, is quoted at about $750 to replace retail, maybe $550 street price. Sort of high.

Seeing as how it is leaking, small pin hole I can't find on the bottom, I figured I've have a look at it and take it apart. Not much to it. Standard top plate with roll over vent valves with check balls, two pickups that are nothing more than rubber hose with screens you cram in the corners, and a lot of foam cut to fit in there just right.

So, now that it is all apart I think I'll try a good old product I've fixed a few motorcycle tanks with - Kreem. Anyone tried this on a fuel cell bladder? The bladder is quite thick, so if it has a hole I think it will be repairable with Kreem. I plan to put the bladder into the can to help it hold shape (it holds shape without the can actually) and then Kreem it up. After that has cured then re-install the lid and foam so we can be on our way. Anyone else have experience with this? If not we'll give it a go and let you know how it turns out!

It'd be one thing to rig something like this on a ALMS car, but this is in a class where stock fuel tanks are legal. This is safer than some 70s era stock fuel tanks even if it has the leak! Well, it is safer than my Jensen tank, but all that car wants to do is lie in a field and rust, and/or, catch fire.

R
 

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Pat

Supporter
Hi Ron,

You may remember I had all those problems with the cell on my GT40. Some of the locals that work with the space program recommended Floats and Fuel Cells in Memphis. They reconditioned my cell to FAA standard and literally better than new with a three day turnaround and very reasonable rates. I liked their work so much I had them do my other cell as a precaution.
FFC :: Custom Work

I'm not affiliated etc.
 

Ron Earp

Admin
Less expensive than $40 of Kreem?

I'd like to use them, but like Fuel Safe when you start working with Fuel Safe or any other company building to aircraft specs. Do you think they would be cheaper than say $500 for a new bladder? I might give them a call. Thanks for the reference. What happened to your bladders/cells? From Fuel Safe they are guarenteed for five years min, no questions. The Z cell is from 1991 so it has missed out on that deal!

R
 

Sandy

Gulf GT40
Lifetime Supporter
Ron, what about using one of the other lower cost fuel safe bladders/internals? Most of the containers are the same maybe one of the lower cost ones would be a better way to go. I would not want to glue a hole in the bladder only to have a problem later when you need to rely on it to hold under pressure. I hate to toss it out, but in the event of a crash would you rather have a new safer cell then the patched one, and is your safety worth more then $40 bucks?

Fuelsafe has a couple of models, the FT3 which is approved for all major sanctioned events, but looks to be the 'plastic' vs the rubber/urethane bladder. Likely much less costly (Might fit the same container). They also have one that is non-approved but is likely the same as the FT3. They might be a good balance between cost and safety.

Sandy
 
I don't know crap about fuel cells, but I do know something about people getting themselves screwed up. Ask yourself this: if you are lying burned in a hospital bed, how much would you pay to get out injury free? how much would your family pay? You got 16 years out of the old cell, money well spent. I'll bet your family would think this is money well spent too.
 

Ron Earp

Admin
I agree it is a little bit of money in the long run, but if it can be safely repaired I don't see where that would be a problem. It is a pin hole leak in a cell and the cell seems quite sound otherwise. I liken it to a motorcycle tank with a tiny leak, it just gets repaired and life goes on. The cell isn't brittle or weak from tests I can do. Cells are repaired at Fuel Safe and other places, but they just don't tell you how it is done.

I might look around for some lower cost cells and bladders from Jaz and others. Fuel Safe is nice stuff but it costs considerable coin.

R
 

Sandy

Gulf GT40
Lifetime Supporter
Ron - I renewed my subscription to the GT40s.com site. I hope this helps get you tracked to a safe solution for the 'Z', I was going to do it anyways, but now seems like a good time :)

Sandy
 

Ron Earp

Admin
Hey Sandy, thanks!! I just finished putting the Kreem in here at work and I think it is doing a wonderful job. Coats well, and drys with a sort of semi flexible feel to it. I'll get some pictures tomorrow or Friday when 100% cured and then test it out. So far I think it is working well.

Those fuel cell companies do something similar as they will tell you that much on the phone "we clean it, pressure test it, check for leaks, and seal it against leaking". So they are using some sort of liquid/spray seal to do the job.

Anyhow, we'll learn something either way here with this experiment.

Ron
 

Pete

Lifetime Supporter
Hello Ron,

It seems to me that Kreem works better when the vessel is rigid and doesn't move alot, otherwise the Kreem lining would delaminate if you will from the wall it was sticking to. it would probably be better to isolate the pin hole or holes, there may be more and use a good epoxy that resists fuels. I know it sounds like more work, but I think it would result in a more sure repair.

Pete
 

Ron Earp

Admin
ECONOMAN said:
Hello Ron,

It seems to me that Kreem works better when the vessel is rigid and doesn't move alot, otherwise the Kreem lining would delaminate if you will from the wall it was sticking to. it would probably be better to isolate the pin hole or holes, there may be more and use a good epoxy that resists fuels. I know it sounds like more work, but I think it would result in a more sure repair.

Pete

That is my only worry too. I think it might work here though because the bladder is fairly firm and once it gets packed with foam and in the can it is more rigid. Not like a steel tank, certainly not, but not flimsy floppy either. We'll see how she goes.

R
 

Ron Earp

Admin
Hey Pete,

I think our fears of cracking were unfounded. I got the bladder coated and the Kreem is dry now. I think because the bladder construction, some sort of "fabric/cloth" and the thinness of the Kreem layer that the coating still flexes with the material. And it is coated completely white on the inside fairly uniformly. I'll give it another 24 hours to cure then put gas in it before I call it a success, but it is coming out better than I expected at this point.

Ron
 

Ron Earp

Admin
Hey Pete,

Looks like our worries over Kreem are not a problem. Got the bladder coated and the coating is flexible with the "fabric" that makes the bladder. I think it has penetrated the fabric and being in the material is somewhat pliable. It seems sound and good to go. I'll give it another day to cure then test with gas before I pronounce it a success, but so far so good.

Ron
 

Ron Earp

Admin
I forgot to post the outcome of this repair but wish to do so for completeness sake.

The Kreem material did a fantastic job. It penetrated the material of the cell and it still remained flexible a week after curing. We filled it up with gas and it has been holding fine for over a month now, no problems at all. Car might be racing in a week so I'll report back if we have issues, but I don't think that is going to happen.

I also talked to two fuel cell repair places and their method of repair they described is essentially the same thing, although they won't tell you what they use. Fundamentally this appears to be the same procedure.

Ron
 
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