Venting fuel/ AN fitting possibly damaged

[Jono.F]

Good day all
Looking for some suggestions please. My new (to me) RV4 has fuel venting out he vent lines. After some research I found the problem to be the vent line where it joins the bulk head fitting where it exits the wing was completely detached. After about four hours i was unsuccessful in getting the nut seated due to limited access. The next day i took my 10yr old with his skinny arms, and he easily worked the nut onto the thread. Except after about 3 full turns on the thread the nut pops completely off. So i assume the thread is damaged. The question is now what? I put my phone in and took a pic, the male thread from the part i can see looks fine, any possible way to get another nut onto the flared tube without removing the whole tank?
thanks
Jonathan

 

[Jono.F]

 

[Jono.F]

 

[andoman]

A couple of thoughts:
-If the male threads are indeed intact, I suspect a cracked female fitting.
-replacing the female fitting requires cutting off the existing flare. This will likely make you vent line too short to reach the male bulkhead fitting. And this supposes that you can manipulate the flaring tool through the access hole. Pulling the tank and cutting access into the rear of the tank will be required.
-if the female fitting is cracked yet treads 3 turns on as you described, it could be prosealed in place. Be careful not to let proseal block the vent if this route is taken.
Hopefully someone will chime in with better suggestions.
Good Luck!!!

 

[Robin8er]

You may just not have the nut lined up correctly and the threads aren’t actually engaging. Pull the nut back and get the line as straight as possible in relation to the male fitting, then try it again. These can be difficult in tight spaces, as you have found.

 

[Jono.F]

You may just not have the nut lined up correctly and the threads aren’t actually engaging. Pull the nut back and get the line as straight as possible in relation to the male fitting, then try it again. These can be difficult in tight spaces, as you have found.

Thanks. I am going to give that another try. Im really hoping its that simple. My son and wife both said they can feel it threading on progressively about 3 turns, then it gets finger tight, then if they tweak it with a spanner, it pops off. If it cross threads, they cant get it on more than a quarter turn. I do think its worth another try though before more drastic measures. I cant maneuver my hand in there, it feels like my wrist needs another joint.. haha.. So i have to take their word for it.

 

[Walt]

Yep, cracked nut most likely.

 

[bjdecker]

The AN nut (B-nut) looks like it's been damaged by the fuel pick-up (flop) tube, and possibly a crack in the breather tube as well. See attached with circled area...