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Fixing a leaking rivet on fuel tank.

High_Flyer

Well Known Member
I've been flying for around 20Hrs now, all good except my right fuel tank has a leak around one rivet on the top side, on second rib from the root, 4th rivet from the back plate.

I have received the fuel tank repair kit from Vans.

If I use repair kit I received I need to remove the tank from the wing, cut a large hole in the back plate to access the insde of the tank to replace the leaking rivet, then rivet the round plate on the big hole I've cut using many "special" pull rivets and sealant.

Is there any reason why It would be worse to only drill out the bad rivet, and repalce it with one of the special pull rivets received with the repair kit?
After all if going the repair kit route I'll have to install many pull rivets instead of just one.

What's wrong with my reasoning?

Thanks,

Alain
RV-7, flying.
 
The only challenge with your proposed approach will be having one "odd" rivet that will be noticeable unless you file it/sand it/smooth it.
 
I may be wrong, but every rivet I have drilled out ended up leaving shavings and pieces on the other side of the drill. Probably don't want to have that stuff in the tank. If you can figure out how to clean it out without taking the tank off, maybe your idea would work.

Taking the tank off is a pain, but probably necessary.
 
I may be wrong, but every rivet I have drilled out ended up leaving shavings and pieces on the other side of the drill. Probably don't want to have that stuff in the tank. If you can figure out how to clean it out without taking the tank off, maybe your idea would work.

Taking the tank off is a pain, but probably necessary.

If I drill the rivet I can do it such as only the head of the rivet in the tank will fall inside, no shavings.
I thing the head will eventually drift to the low point around the drain. I can check reguarly if it's there by removing the drain, say at each 100Hr/annual inspections.
 
Didn't Bob Collins do a repair on his -7 before it was sold? Shot a wet Cherry in there, with success.

Might search his posts for the whole story.
 
I just did one on my 25 year old purchased -4, that was below the leading edge. When it started weeping, I poked at it, and discovered that there was no rivet there. Just a dimple, filled with (ancient) tank sealant. The builder had apparently drilled an extra hole at that rib location, and when he couldn't grab the rib flange, just filled the dimpled hole with sealant. Lasted from 1992 until now, with fuel on that spot way over half the time.

I used a dental pick with a short hook bent on the end to dig out all the sealant I could, then a cloth soaked with gas (*don't* use MEK, unless you want more leaks in that area) prodded into and around the hole with the dental pick. Let it dry, mixed some 10 year old proseal from my freezer, & popped a rivet into the hole. Not going to win any best of show awards, but t's been several weeks, and it hasn't leaked yet....
 
I had several rivets on my RV6 that were seeping fuel through a pinhole at the edge of said rivets. All I did was mix a small amount of Proseal and then pressed some into the holes with my finger. I then wiped the surface clean, let it set for a day or so and never saw a blue spot for the following eight years we owned N100NT.
 
I had a rivet start seeping several years back. Right wing top, a little back from the lading edge. I very carefully drilled the rivet head. popped it out with a dental pick. I then again very carefully pushed the shop end into proseal bead on the inside of the tank, capturing it. I then cleaned the resulting hole with solvent using a cotton swap. I then cleaned a pop rivet with solvent and coated the rivet and the hole with fresh proseal, inserted the rivet and squeeze slowly. I then filled the resulting hole with proseal wiping off the excess. Yes I have a pop rivet showing in my right tank, but I do not have a seep and the smell of gas in my hangar. Dan from Reno
 
Thanks

Thanks for the replies.
I'm away on a trip right now, will be home next monday so I have a week to think about it...
 
Just to add to the data on this technique, I developed a weeping rivet near the leading edge of one of my tanks that was very successfully dealt with using the syringe technique.

This happened after flying my 900h, 13y old RV8 through some pretty heavy rain. Some paint must have peeled back from the top of a rivet, exposing a leak which made itself apparent the next time I went flying (big blue halo around it etc). While bracing for having to remove the tank and cut a hole to fix from the inside I decided to try this technique as there appears to be no downside.

I did not thin the proseal at all, but I did use a 5cc syringe instead of a 10cc syringe (you can exert more pressure at the tip as the plunger is about half the surface area of a 10cc syringe).

Its been 6 weeks and another 20h of flying (at least) and the repair has held up nicely.

Jon Weiswasser
N898JW
 
I’ve just had several rivets leak on my 100 hour RV7. Started after I was trying to find a fuel leak inside the cockpit. I put about 1 psi into the left tank and found the leak at the loose banjo fuel connector from the left tank at the fuel selector. But putting the pressure in the tank caused about 8 rivets weep on the bottom and 3 on top putting blue stains around them. Drained the tank let it dry, then tried the thin theadlocker. To me it didn’t seem that was robust enough. I then mixed a small amount of JB weld original and used a finger to push into the rivet microcracks. After a couple days filled the tank and so far after several days is dry. Just my 2 cents. I’ll see if it lasts.
 
I've been flying for around 20Hrs now, all good except my right fuel tank has a leak around one rivet on the top side, on second rib from the root, 4th rivet from the back plate.

I have received the fuel tank repair kit from Vans.

If I use repair kit I received I need to remove the tank from the wing, cut a large hole in the back plate to access the insde of the tank to replace the leaking rivet, then rivet the round plate on the big hole I've cut using many "special" pull rivets and sealant.

Is there any reason why It would be worse to only drill out the bad rivet, and repalce it with one of the special pull rivets received with the repair kit?
After all if going the repair kit route I'll have to install many pull rivets instead of just one.

What's wrong with my reasoning?

Thanks,

Alain
RV-7, flying.
I WOULD PRESSURIZE THE FUEL TANK - (CAUTION: 1 OR 2 POUNDS OF PRESSURE ONLY) - DRILL THE RIVET AND REPLACE WITH THE SAME RIVET SMOTHERED IN PROSEAL WITHOUT SQUEEZING THE RIVET AND OPENING THE FUEL TANK. I HAVE USE THE "KIT" TO REPAIR TANK LEAKS AND ENDED UP WITH A NEW FUEL TANK. WHAT A MESSY AND ARDUOUS JOB!

USE COUNTERSINK TOOL TO CLEAN THE HOLE BEFORE INSTALLING THE NEW RIVET. I THINK REMOVING ONE OR TWO RIVETS WILL NOT HAVE A NEGATIVE AFFECT ON THE TANK'S INTEGRITY.

ANYONE DISAGREES?
 
EZ-"OOPS"

I took Paul's idea to make a "replacement" sealed pull rivet a step further, and remade the head into the equivalent of a -3 bucked rivet, through some lathe work and the use of a 120 Ton hydraulic press I have access to, for cold working the head shape - including changing the included angle for pulled rivets from 120* to the AN standard of 100*. All of which allows (if the op chooses) drilling out the leaking -3 bucked rivet (to 1/8") and using my EZ-OOPS with ProSeal as a replacement. I have had a "leak" test going for some months now with no failures. You may need to lightly "swirl" a machine countersink (100*) in the repair hole to insure a good seal with the replacement - check as needed before pulling the replacement. If you would like a couple, I'd be glad to send them - the only caveat is the length. For skin to rib contact use AK41H, for skin to rear baffle contact use AK42H.

HFS
 

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I Had a few rivets seeping and repaired with them with Green Loctite 290 which is a wicking grade thread locker. I trimmed the tip from a syringe and placed a o ring on it and applied pressure over the rivet for a few min, and repeated it three times and then let it set. Refueled after a few days and having seen any sign of a leak since.
 
I have a weeping rivet in one fuel tank as well, so this thread caught my eye. Kitplanes had an article earlier in 2023 that interested me. It is very similar to what @HFS did.

But now I see there are many options.

 
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