fuel tank weeping rivet

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farmrjohn

Pre-takeoff checklist
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farmrjohn
Can a material like Pro-Seal be used to repair a weeping rivet on a fuel tank without disassembling the tank?
 
farmrjohn said:
Can a material like Pro-Seal be used to repair a weeping rivet on a fuel tank without disassembling the tank?
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Yes. Can you get to the rivet through the fuel filler or the fuel level sender access plate? If so, you can clean the area and apply proseal over the rivet on the inside of the tank. Otherwise, green locktite (which will wick into the leaking area around the rivet) can be applied externally. Obviously you want to empty the tank before undertaking any of this.
 
Reading the installation instructions they say to consult SAE Aerospace information report AIR 4069.
What plane make and model. I would think a sealant like that is meant to seal from the inside of the tank.
 
Proseal is for external use only on fuel tanks. It is allowed for water tanks, though...
 
You can do that, but the rivet is vibrating in the hole and the sealant may not be a long term fix for the leak without addressing the cause.
 
farmrjohn said:
Can a material like Pro-Seal be used to repair a weeping rivet on a fuel tank without disassembling the tank?
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What does the airplane manufacturer say to use?

Pro seal isn’t exactly a specific product
 

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Seal-All is a much thinner product than Pro-Seal and will flow under the rivet (in warm weather) and seal against fuel leaks.
 
Proseal is used to seal many tanks, including those on Pipers, Mooneys, some Cessna's, and the RV series. It is generally manually applied and can be mixed by hand, by specially designed cartridge mixing tips, and possibly by other means. I've worked with both the paste version (think peanut butter) and the flowable version (think molasses).

Over time, it may degrade which is why we hear about resealing tanks and weeping rivets, like in the OP's situation.
 
farmrjohn said:
Can a material like Pro-Seal be used to repair a weeping rivet on a fuel tank without disassembling the tank?
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Not near enough info. We talking aircraft? If so, is it a wet wing or have a bladder? Etc.
 
Further information: The tank is the fuselage tank for an Alon A2 Aircoupe, the type holder is Univair, and the rivet in question is on the bottom of the tank. The tank is behind the instrument panel, and the cabin side of the firewall. Pics are of a sample tank, mine is still installed.
 

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I saw a guy use JB weld once....took the paint off to bare metal then glued a JB weld round dime sized patch over the rivet....and it held that way for years. The patch was painted white....and you couldn't see it unless you were looking for it.
 
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There are lots of options. Plenty in the RV world have cut an access panel in a tank, cleaned and resealed, then installed a reinforcing doubler and an access panel to close the tank. Probably a one day project if you want to do it. But that kind of repair would require an IA to file a 337 (I think), so you'd want his/her approval before starting.
 
If you can get to the rivet when the tank is emptied, drill it out and installed it wet with proseal. Seal the backside with more sealant and you will be good to go. At least until another rivet starts to seep.

Obviously clean up the tank really well before you fill up the tank.
 
You can also clean the paint off the outside of the rivet, thin down pro seal, pull a SLIGHT vacuume on the tank and brush the proseal on the outside and hold the SLIGHT vacuume on the tank and it will pull the pro seal under the river and might seal it up.
 
Josh Neumann said:
If you can get to the rivet when the tank is emptied, drill it out and installed it wet with proseal. Seal the backside with more sealant and you will be good to go. At least until another rivet starts to seep.

Obviously clean up the tank really well before you fill up the tank.
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how ya gonna buck that? o_O
 
I guess I take back all those rivets I have done. Yes there are rivets in many tanks that you cannot possibly get to. But there are certainly many you can. For example Piper tanks. You can most certainly buck many of those. I have no idea what airframe the poster is dealing with but it is a possibility.
 
I should rephrase my question- Is there an approved method or methods to correct a leaking rivet on a fuel tank without removing the tank? In this case there are horror stories aplenty about removing Ercope/Aircoupe fuselage tanks involving lots of time and the need for 140# spider monkeys to gain access. With the AMU cost associated with removing the tank looking at other repair methods at specialty repair shops becomes a potential cost effective option. (It's too bad Cali. doesn't allow gum that holds up to 100LL)
 
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There are pulled rivets available that are sealed on the shop side of them. Essentially the mandrel doesn’t go all the way through the rivet. Thus with a dab of proseal you can replace a rivet from outside the tank. Tricky part is drilling out the offending rivet without leaving debris inside the tank. Aircraft Sruce has them.
 
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I've looked at FAR 43.13 (a) and AC 43-13-1B and 2B and didn't find a definitive answer if Pro-Seal or similar use on the external surface of the tank and rivet would be considered acceptable to the Administrator or not. I did find an oblique reference in AC 43-206 Appendix 1, table 1-1 that indicates it might be. I'm hoping to have a good grasp prior to discussing with the shop tomorrow morning on potential less expensive options to pulling the tank. Any thoughts if using the externally applied sealer is an acceptable method?
 
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farmrjohn said:
I've looked at FAR 43.13 (a) and AC 43-13-1B and 2B and didn't find a definitive answer it Pro-Seal or similar use on the external surface of the tank and rivet would be considered acceptable to the Administrator or not. I did find an oblique reference in AC 43-206 Appendix 1, table 1-1 that indicates it might be. I'm hoping to have a good grasp prior to discussing with the shop tomorrow morning on potential less expensive options to pulling the tank. Any thoughts if using the externally applied sealer is an acceptable method?
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Go read the silk thread discussion from a few weeks ago. o_O

PRC or similar is a good product for sealing fuel tanks, but gooping it on over top may help in the short term, but will usually end up leaking around the sealant. Then more is added and round and round you go. Just ask someone with a wet wing Cessna with leaks how they finally got theirs to stop leaking.

When was your tank last removed? I bet it hasn't been in a long time and that the leak you are seeing is just the tip of the ice berg.
 
farmrjohn said:
didn't find a definitive answer if Pro-Seal or similar use on the external surface of the tank and rivet would be considered acceptable to the Administrator or not.
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FYI: there is not a definitive answer for every possible maintenance task on an aircraft. Never has been. The closest you get is in Part 43.13(b):
"(b) Each person maintaining or altering, or performing preventive maintenance, shall do that work in such a manner and use materials of such a quality, that the condition of the aircraft, airframe, aircraft engine, propeller, or appliance worked on will be at least equal to its original or properly altered condition."

This is why your mechanic gets paid the "big bucks" to make that determination and sign their name to it. It is what it is.

But congrats to you for wanting to learn and engage with your mechanic.
 
farmrjohn said:
I should rephrase my question- Is there an approved method or methods to correct a leaking rivet on a fuel tank without removing the tank?
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Bear with me while I ask a question.
Can you reach the rivet in question.
 
There are a bunch of these two part catalyzed sealants that fall under Mil-Spec-8802-D, none are receptive to oily surfaces, and all must be top coated to with stand exposure to aeromatic fuels.
these sealents are mostly meant for caulking gun applications, and when the surface isn't really clean they don't stick.

I'm always for the long term fix wen it comes to fuel leaks, and pro seal isn't one.
 
JAWS said:
http://www.ercoupe.info/?n=Main.HeaderTank
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Thanks, aware of that site. The Alon tank is different and is welded.

Tom-D said:
Bear with me while I ask a question.
Can you reach the rivet in question.
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It's one of the rivets on the bottom of the tank that is visible in the second pic I posted. With a good bit of contorting the head of the weeping rivet is accessible while the tank is still installed. I'm not sure if the tail can be reached through the filler neck or not but would suspect not.

JAWS said:
Go read the silk thread discussion from a few weeks ago. o_O

PRC or similar is a good product for sealing fuel tanks, but gooping it on over top may help in the short term, but will usually end up leaking around the sealant. Then more is added and round and round you go. Just ask someone with a wet wing Cessna with leaks how they finally got theirs to stop leaking.

When was your tank last removed? I bet it hasn't been in a long time and that the leak you are seeing is just the tip of the ice berg.
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When? According to the logs not since it was manufactured in 1966.
 
Tom-D said:
I've never seen a bladder that uses rivets to seal.
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Neither have I. The context of my comment was directed to the OP to offer more information on his problem.

However, I have run into several individuals who tried to stop a fuel leak at a screw or rivet... Only to be informed that it was the fuel bladder above that was leaking and not the screw/rivet they were trying to seal.;)
 
farmrjohn said:
The tank is behind the instrument panel, and the cabin side of the firewall. Pics are of a sample tank, mine is still installed.
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At least the tank and rivet are easily accessible.

:confused: :p
 
3393RP said:
At least the tank and rivet are easily accessible.

:confused: :p
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Easily accessible? I wish. Perhaps if one was a nimble, skinny teenager or the plane was partially disassembled it would be easily accessible. I was hoping to avoid the expense of having the tank pulled since I don't have an A&P to supervise and sign off my own work. Sigh, the joys of plane ownership…
 
You missed my attempt at humor.

I hope you can get it repaired without tearing everything apart.
 
3393RP said:
You missed my attempt at humor.

I hope you can get it repaired without tearing everything apart.
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I did initially-I was just coming back to edit my post to reflect that but your response beat me to it (still getting the hang of those emoji things)
 
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