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Leaking Fuel Tank Rivet

f14av8r

Well Known Member
Okay, so I've tried all the tricks to get this rivet to quit leaking. No amount of pressurized cattle syringe injection of any type of sealant has worked. They slowed the leak quite a bit but have not stopped it completely. So, I'm ready to take the plunge, drill this sucker out and replace it with a new, sealant coated rivet so I can get the leak stopped and the paint back in order!

The plans call for a AN470AD4-4 rivet. Obviously, I'll need a blind countersunk rivet for the replacement. To save me having to learn all about Cherry Max rivets again, would one of you rivet wizards tell me what I should use here please?
Thanks,
Randy

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Your looking at the wrong drawing for the rivet that is leaking.
The one in the picture is probably an an3-3.5 I don?t think you will find a pop rivet that will work in this size and location. Your best bet will be to remove the tank and open up the rear baffle to access the rivet so it can be replaced and resealed.
Do a search for tank leak repair and you will find many threads on this problem.
 
Your looking at the wrong drawing for the rivet that is leaking.
The one in the picture is probably an an3-3.5 I don?t think you will find a pop rivet that will work in this size and location. Your best bet will be to remove the tank and open up the rear baffle to access the rivet so it can be replaced and resealed.
Do a search for tank leak repair and you will find many threads on this problem.

Thanks Dave! But, I'll let it leak at the rate it is leaking FOREVER before I pull the tank and open it up to fix that one problem.

I sure can't figure out what drawing I should be looking at if not that one. That's why I need one of you builder wizards to help me out!
 
Back in the old days, one of the factory guys suggested using one of the 1/8" sealed end pop rivets you use to attach the aft baffle to the ribs. You drill the offending hole out to 1/8", countersink it a bit if it is dimpled, then put a dab of proseal on the rivet and install. You come back once the proseal is cured and file or sand the rivet to some acceptable level of flushness.

After that, you fill and paint...
 
Old rivet

Watch for the shop head of the current rivet when it is drilled out. FOD in the fuel tank is never a good thing.
 
What Kyle said.... should work fine and be a relatively simple install. Make sure you clean the area perfectly to assure the proseal sticks and let it cure for a few days. Then all you have to worry about is the cosmetics - no problem. If you need a couple of those sealed end pop rivets, let me know, I?ll send you a couple.
 
Why not trying the green Loctite method to see if that will fix it before opening the back>

As I said in the original post, I've tried all the external injection techniques offered on the website including green locktite. It helped but it did not solve the problem.
 
Fuel Tank

My brother and another AME fixed my leaky right fuel tank 2 years ago. Had to take it apart clean up all the old sealant, reseal and rerivet it. Then took it to an auto body paint shop to get it repainted. Everything turned out great, no more leakage and tank looks great. A lot of work but we'll worth it. Never had to do the left tank so far, fingers crossed. Airplane is 20 years old this year but only has 250 airframe hours on it.
 
Watch for the shop head of the current rivet when it is drilled out. FOD in the fuel tank is never a good thing.

+1. I can?t see how you can avoid getting either swarf or a rivet head in your tank ( or both) when you drill out the rivet ....unless you remove the tank and open it up. It?s not the end of the world to remove a tank.
 
Leaking fuel tank rivet

Randy,

The RV-4 tank is not as hard to take off as you think. It’s a little time consuming unscrewing all those **** screws but the inside fuel line B nut will come off pretty easy. You can do the whole removal start to finish in an hour or two working slowly. That’s really the best way to do the repair, check the rest of the tank, make sure there’s no FOD and check all the other rivets while you’re in there. Like Brian said above, you can do all the cosmetics and repaint the tank while it’s off the plane or take it to a paint shop.

Don’t be too worried about taking that tank off, it’s really not that hard.

Good luck- post a progress report!
 
Pop Rivet

Randy,
Use a lot of sealer when you install the pop rivet. Work it into the rivet before you install it. I have done it several times with no more leaks....
 
Personally, I wouldn't worry too much about the loose shop end of the old rivet.
It'll probably stay in the old proseal instead of falling into the tank.
Also, the finger strainer at the fuel pick up will catch it, assuming it makes it past the internal ribs.
You can always take out the sump drain and run some gas through it a few times to clean out debris. You'd be surprised at the things I have found that way. Once, I found the finger tip of a latex glove that was in there likely since it was built 17 years prior.
good luck.
 
I have fixed several leakers.

drill it out and replace with a -3 pulled rivet.

butter it up inside and out and all over with Proseal

Insert and pull.

clean surface with an bit of acetone.

Removing the fuel stain is a different story.

I could be wrong, but I believe the fuel color gets under the clear coat.

I haven't wanted to sand and repaint just yet.
 
I could be wrong, but I believe the fuel color gets under the clear coat.

I haven't wanted to sand and repaint just yet.

That's exactly what happened to me. I took the plane back down to the painter and he sanded it all off and reapplied clear coat. Needless to say, a very careful sanding job, probably wet sanded with very fine sandpaper. You can't tell there ever was a fuel stain.
 
For some single part paints, just parking it in direct sun light will fade it away, or try a UV lamp on it. Worth trying before going the re-paint route.
 
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