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How to remove fuel tank.

Larry DeCamp

Well Known Member
I want to double check my second hand (bought the project) tanks for bubbles before painting. My concern is no access to the rear, so they must come off.

I am aware to put thin a sheet under the dimpled flanges to lift the dimple. My problem is the curved seams ( top and bottom ) are pretty stubborn. My idea is to rotate the the tank from the fuse end to walk it off the curved edges without distorting something. These joints are really tight. Nice workmanship, but there is downside.

Advice appreciated.
 
removing

Yup nothing in back to worry about except maybe fuel level sender wires if it has a inverted flop tube.

Remove all screws along top and bottom edge. Disconnect all fuel and vent lines and fuel sender wire. Remove wing root bolt near front of tank.

It can be a bit stubborn to get started since the dimples can hold it in there pretty good. I started gently pulling on wing root angle fitting and rib flange to get it started. Be careful though once its comes loose it can pop off quickly - have a good grip.

If it gets really stubborn remove fuel cap and you have another place to pull.
 
Thanks STU

The left tank has what looks like a sender. It had a flop tube but I removed it.
There are no wires visible between tank and spar.
So, If I am willing to risk the sender is sealed well, are there no other risk sources on the back of the tank ? The builder said they tested good, but I know how stressful it is to fight leaks (loctite, whichcraft , etc.)
 
The left tank has what looks like a sender. It had a flop tube but I removed it.
There are no wires visible between tank and spar.
So, If I am willing to risk the sender is sealed well, are there no other risk sources on the back of the tank ? The builder said they tested good, but I know how stressful it is to fight leaks (loctite, whichcraft , etc.)

So to be clear, if this is a RV7, there is multiple bolts (AN3) along the back side of the tank attaching it to the spare. They are accessed from the access panel at the bottom of the wing (three bolts per bracket) and I believe there is a total of 5 brackets which you will need to remove all of the bolts before the tank can be removed. Once all the bolts are removed, then the tank should come off with a bit of rocking.
The back side of the tank (the baffle) is the hardest part to seal and more common place to leak so it is a good idea to check that if you have any doubts. Be careful not to put too much air pressure for testing. Just follow the plans.
It is a good idea to do it so you can get to know your new plane/kit.

Congrats on the new purchase and good luck
 
Look at the plans and determine how many bolts are holding the tank on. Count the removed bolts to be sure you have them all out. Then slip a piece of mylar under the skin and start working it along to disengage the dimples.

-Marc
 
Reading Larry‘s signature, it is a -4.
So Stu is correct, no other rear opening, but the upper & lower flanges, on a Plans built tank, but the fuel sender for the flop tube version.
 
Tank removal pics?

Any pics of the process of removing the tank? I believe I have a fuel sender replacement in my future. I'm curious what lays ahead.

Thanks!
 
Any pics of the process of removing the tank? I believe I have a fuel sender replacement in my future. I'm curious what lays ahead.

Thanks!

You should be able to replace the sender without pulling the tank. The gap at the wing root is adequate for the task, and it is (IMO) much easier than removing the whole tank.
 
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I'd say most leaks happen in back of tank where rear baffle is installed but it does vary. I'm assuming this tank has never had fuel in it to see if it leaks and you're just taking precaution before paint?



The left tank has what looks like a sender. It had a flop tube but I removed it.
There are no wires visible between tank and spar.
So, If I am willing to risk the sender is sealed well, are there no other risk sources on the back of the tank ? The builder said they tested good, but I know how stressful it is to fight leaks (loctite, whichcraft , etc.)
 
30 yrs

Since tank installed, came out easily. Leak location seems to be just outside root rib, rear baffle area. Never been wet outside of wing, just stains. No zee brackets on 6 models.
 

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You should be able to replace the sender without pulling the tank. The gap at the wing root is adequate for the task, and it is (IMO) much easier than removing the whole tank.

I was hoping this was the case, but I now believe that if you have a flop tube in that tank, the sender can't be accessed at the wing root.

I really hope someone tells me I have that wrong.
 
flop tube in that tank

Correct. This what the rear baffle looks like on tank with a flop tube (pic ca. 1998 vintage ;) ).
Removing the wing/fuse fairing is a quick job (usually) and will give you the info.

As far as the sender installed in the wing root ribs, there ain’t much space to work there. Very easy to strip the screws heads…
 

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Correct. This what the rear baffle looks like on tank with a flop tube (pic ca. 1998 vintage ;) ).
Removing the wing/fuse fairing is a quick job (usually) and will give you the info.

As far as the sender installed in the wing root ribs, there ain’t much space to work there. Very easy to strip the screws heads…

A tool something like this (I have a different one) makes it pretty easy.

https://www.amazon.com/STREBITO-Scr...648660412&sprefix=racheting+90,aps,153&sr=8-5
 
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