Fuel Level sending unit access?

I have determined that I am receiving an erratic signal from the stock float type fuel sending unit in the right wing of my -4. Not knowing how big the float unit is I need to understand if it Is possible to replace it without removing the fuel tank? It would be nice if the geometry worked out but there isn?t much space between the wing root and the fuse.

Thx!

If the access plate only has a gasket, then maybe. If it has Proseal on it, it will be hard to get off even with the tank removed.

Same boat.....

I did not build, but my A&P/IA and a multiple RV builder said it is possible to do. Leave float in and change out the rest. Usually not a physical float issue, but the actual sender / potentiometer that is buggered up. All I got .... on my to do list. In mean time , fly by time on my right tank. Following here to see what others have to say. Is 3.5 oz out proseal enough to do this job eg: replace float sender x 1?

Just found this post Kooshball

http://http://www.vansairforce.com/community/showthread.php?p=1436103#post1436103

Kooshball said:

I have determined that I am receiving an erratic signal from the stock float type fuel sending unit in the right wing of my -4. Not knowing how big the float unit is I need to understand if it Is possible to replace it without removing the fuel tank? It would be nice if the geometry worked out but there isn’t much space between the wing root and the fuse.

Thx!

Click to expand...

In my RV-4 I used undrilled root ribs, like in the RV-8. There is no big access panel. I just drilled the hole for the sender and its screws.

So it is possible to remove the sender without removing the access panel. Not sure if there is room with the tank installed.

I would try it. If you can't, then remove the tank.
The first obstacle will be to remove the screws. If allenhead screws were used, it will be a lot easier.
Next problem will be to separate the sender from the access panel or rib.
Finally, can you pull it out far enough to remove (and reinstall) the float wire from the sender.

Note that the RV-4 tanks should be a lot easier to remove than the later tanks. There are no Z-brackets that need to be unbolted from the inside of the wing, just the exterior screws. Main problem will be not to ruin your pain job -- a careful job with a razor blade or similar should do it.

Finn

remove fuel tank

I had to service one of my tanks on my 4 several years ago. I never considered trying do the procedure with the tank still in the airplane. The access port was sealed with proseal. Buy or borrow some screw paint cutters and remove the tank...not that hard on a 4 as previously mentioned. if yours is
sealed with proseal, you will find that it takes patience and care to get under the edge of the proseal and gradually work the access port free. Trying to do this while the tank is still on the airplane requires too much in the way of gymnastics for me and real big chance of buggering up the rib when trying to free up the access port. Not worth it!