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Weeping Fuel Tank Skin Rivet

N184DA

Well Known Member
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I know this has been discussed, re-discussed, hashed and re-hashed over the years.

But I am looking for a "consensus" on the best rivet to use for a single leaking fuel tank rivet, in a visible area of the top skin.

From reading the archives, I have seen three popular options:

AD-41H Closed-End universal head
MK-319BS Monel flush head
AK42H Closed End flush head

Curious as to after time, if there is a preference.

I like the MK319 because of the size: shank & head are only slightly larger than the standard -3 solids in use now. But the lack of a closed-end bothers me. In my mind, I have only one-shot to get this right as I do not want to have to drill out a blind rivet with a steel/monel stem.

I am leaning to the albeit larger, AK42H closed-end flush. If done correctly and dressed up with a good touch-up paint, it would be hard to notice.

Just curious as to how those MK319BS replacements are holding out after time.

Thanks!

(And no, I am not leaning towards tank removal to address this the most "correct" way via the rear bulkhead, at least not yet :) )
 
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Use the AK42H. Add proseal in the hole and on the rivet during install, including a dab on the rivet shank hole to make it disappear after you paint. I fixed a couple of other people’s tanks this way.

No one will ever see the difference in rivet head size (until you point it out).

Carl
 
Use the AK42H. Add proseal in the hole and on the rivet during install, including a dab on the rivet shank hole to make it disappear after you paint. I fixed a couple of other people’s tanks this way.

No one will ever see the difference in rivet head size (until you point it out).

Carl
Were you able to “capture” the old shop head in the pro seal? Or is it loose in the tank.
 
Me Too

Hey Derrick, how are you doing? Enjoying Tacoma?

Have you repaired your leaking rivet? I found one leaking too. I am curious about the repair. Drilling out a rivet on a fuel tank sounds a little scary. Drain it out obviously. Then blow it out with compressed air to evaporate the remaining fuel first?

I was going to pull out AC41-30 to see what’s in there.
 
Hey Jim,,

All is well.
Yes, I did replace the rivet. In this particular case, I was fortunate in that the rivet is located on the top, leading edge on the rib adjacent to the filler cap, with the flange pointing in the “correct” direction.

So I didn’t drain the tank completely, only enough to “dry-out” that one bay. (Truth is, there was very little fuel remaining, maybe 5 gallons)

Carefully drilled until the head and I was able to pop it off using a punch.
After a little additional drilling into the shank/shop head, I was able to lightly tap and push the shop head free into the tank.

I enlarged the opening to 1/8” (#40) and kept a vacuum running at the drill bit to suck up any shavings. No, I did not vacuum the inside of the tank because of the risk with vapors & electric vacuum motor. And yeah, I am aware that there was still a risk vacuuming the outside but I only had the vacuum on the tank for a couples seconds, max.

I did have to dress up the dimple a bit to accept the slightly larger AK42H.
Again, using a vacuum on the outside of the tank.
It only takes a second or two.

Gooped up the rivet & hole, and installed the rivet.

My only mistake, I used too much proseal on the top of the rivet, I should have cleaned it off better.

I was able to retrieve the original shop head through the filler neck by using a stick and tape, and cleaned up any visible residue shavings in the same manner. There wasn’t much, if anything that I could see.

That’s about it.

Would be a little more complicated if the rivet was in a more “unfriendly” location.
 
I got into some small hail under an anvil cloud out over the Grand Canyon a few years ago, nothing larger than a full rain drop in size really, but it left a couple small dents on the leading edge of my wings if you know where to look. Right after that I had three leading edge tank rivets that started to weep, presumably from the hail impacts. I drilled them out and replaced them with the -42H rivets twisted in Proseal and no more leaks - that was roughly 500 hours back.
 
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