Tank removal or the big inspection panel to repair fuel sending unit?

My RV 4 fuel tank sending unit was showing some staining so like a dummy I tried tightening the screws and now I have a drip. So I drained the tank and went to remove the screws on the sending unit and it appears that there are nuts on the screws and not nut plates as they just keep turning and are not backing out. So I'm thinking the fellow that built the plane did not use nut plates.

So, is it worth the effort or even possible to try and remove the big inspection panel to make my repair on the sending unit and maybe add nut plates at the same time?

Or do I bite the bullet and remove the tank to make the fix? The tanks were
removed 4 or 5 years ago and were cleaned up and resealed so I should be good on that end. It's only the sending unit that needs resealing at this stage.

Thanks

Tim

Remove the tank

My experience has been it's easier to remove the tank to work on it then using the inspection cover through the wing/fuselage gap. It may take extra time to take them off but worth it. Since yours have already been off once since initial construction it shouldn't be tooooooo difficult to un-mate them from the spar. And it will be MUCH easier to do your leak repair and then reseal the inspection plate. Good time to check for soon-to-be-leaks too, like up around the front rib tips.......

It is very possible to remove the big access plate and deal with the sending unit that way. It would be similar to the work necessary to complete the fuel pickup tube service bulletin from 10+ years ago. The wing root access is tight, but (IMO) working in that tight area is preferable to pulling the whole tank, just because it should be faster.

Reasonably easy --

I removed and replaced a -4 tank last year ---- not a bad job, if you have enough popsicle sticks. Goes pretty easy with two people.

R.

Definitely remove the tank - its not that difficult a task and makes access to the access panel so much easier.

Depends on the paint job (if any).
If there is heavy paint over the screws and skin seams, there is no way I would remove the tank instead of just removing the access cover.
There would be zero time savings, and the paint on the tank would never bee the same.
Working in the tight space to remove the cover is no more difficult than a lot of other maint/repair tasks.

Easy

Piece of cake, less that 20 mins to remove the screws, disconnect the lines and remove the 1 bolt and have the tank on my bench.

I would not hesitate to do it again this way. In all fairness the tank was out 4 years ago so that may have made things easier but still. It beats working in the wing root.

Tim

Sealing

https://www.vansaircraft.com/pdf/revisions/RV-ALL_05.pdf

You might want to read this info on tank sealing. Wish I had paid
A little more attention when I worked on my tanks. I had less than
perfect results ...
Also if your sending unit is older you might want to replace it since
You are doing all this work.
Cheers.

Done and piece of cake. Removing the tank is really the only way to do it. A lot easier than trying to mess around in the wing root at least with my big mitts.