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Fuel tank removal

Mark Cigal

Mark Cigal

Active Member
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I completed my RV8 in 2004. After 20 years and over 1,000 hours of flight, I have developed a leak in the left fuel tank. It seems to be at a seam on the rear of the tank about 10 inches from the wing root.I want to fix this the right way, and feel that removing the tank is going to be the best way. Here is the problem........ we all know how many screws have to be removed. I have not been able to get even ONE loose ! The plane was painted with a three stage catalyzed paint. I've tried cutting around the circumference of each screw head with an exacto knife to no avail. Will I have to resort to using an EZ out on every screw ? I would be very grateful for any tips from those of you who have done this job in the past.
 
Mark Cigal said:
I completed my RV8 in 2004. After 20 years and over 1,000 hours of flight, I have developed a leak in the left fuel tank. It seems to be at a seam on the rear of the tank about 10 inches from the wing root.I want to fix this the right way, and feel that removing the tank is going to be the best way. Here is the problem........ we all know how many screws have to be removed. I have not been able to get even ONE loose ! The plane was painted with a three stage catalyzed paint. I've tried cutting around the circumference of each screw head with an exacto knife to no avail. Will I have to resort to using an EZ out on every screw ? I would be very grateful for any tips from those of you who have done this job in the past.
Click to expand...
I'd try a new bit on an impact driver starting with a light setting, using lapping compound on the tip of the bit and see if you can break them loose that way. Up the power on the impact driver as you feel necessary. Beyond that? Uggh, drill 'em out, Ez-out, etc. Good luck.
 
This with new bits often and a little dab of valve lapping compound should bring them right out after you get the screw slots clean of all paint. If they are painted it’s gonna be a chore.
EF27C6B9-B016-4489-A346-542C5BC9BD56.png
 
On cars and motorcycles, I grab the impact screwdriver. No idea if it would work on tank screws. It definately removes screws on my 1988 Samurai.

This is similar to mine.
Aiourx 1/2" Hand Manual Reversible Impact Driver Set, 13 PCS Impact Screwdriver Kit, S2 Steel Bits Repair Tool, Disengage Rusted Fasteners or Frozen Bolts https://a.co/d/10TAb5l
 
There are Phillips extractor bits. I’ve had to do this on one screw. The others needed a lot of convincing by leaning into the screw with a brand new bit. I didn’t use any speed tools for fear of stripping the head. Try cutting the paint and spraying some lube to sit over night. Put plane out in sun to get some heat into at least the top screws.

Needless to say the real fun begins when you get to the Z brackets.
 
Perhaps using a paint cutter will free the screws better than an Exacto knife.

www.yardstore.com

Paint Cutter #10

PN: 13403Paint Cutter Features a spring-loaded pilot that centers the cutter over screw head while cutter scores the paint around it. Greatly reduces paint chipping and flaking around screw heads. We recommend using the cutter in a microstop so the
www.yardstore.com www.yardstore.com
 
Hi Mark,

If you are repairing your fuel tank leak and plan on repainting your tank mask off the seam between the tank and wing with aluminum tape and carefully apply gel type paint stripper to the screw heads. It would take less time to repaint the tank then fighting with the screw extractors.
 
There is a difference between standard Phillips bits and the JIC Phillips bit - the standard Phillips is designed to "cam out" if the torque is too high, and ends up rounding off the corners on the screw head. Get a real JIC phillips bit, they fit exactly the contour of the screw head. It will either come out, or shear off. If you are already in the situation to consider using an EZ-out, this is your best bet. An impact driver, as mentioned earlier, works best in this situation.
 
Wait. Wait. Wait. Try to use a paint cutter like these -

www.panamericantool.com

Paint Cutters

Designed to help reduce paint from chipping during the screw removal process. The Paint Cutter is used to cut a ring in the paint around the head of the screw, reducing the chance of excess paint chipping. Use with Paint Cutter Arbors or Dual Threaded Drill Extensions
www.panamericantool.com www.panamericantool.com

this is what they use on Dassault aircraft.

opens the bond, then you can un-torque the screw head with less damage.

oh, Backstabber beat me to it.
 
I've removed several tanks for repairs and the paint cutter works great. I've ended up with a couple of recalcitrant screws and had to remove one with a screw extractor, and on the other I was able to use some needle nose vise grip pliers inside the wing to turn the shank of the screw just enough to then get the vise grips on the head of the screw to loosen it enough to remove. Definitely get the correct phillips type bit. The Wiha brand screwdrivers from Germany work great.
 
The best method I have ever found for removing tough screws is to put a screwdriver bit adaptor on the end of a socket 3/8” drive speed handle… new bit and really good fitting one…
You press your body weight with your chest or shoulder against the handle end of the speed handle… for really stubborn, I have tapped with a ball peen hammer lightly, till the screw turns. The flex in the handle provides the necessary pre-load to help not strip the head.

I’ve used this technique many hundreds of times and even removed some pretty beggared up headed screws that I didn’t think would come out.

Patience is a key. Once it’s un-seated a tiny bit of PB Blaster or similar works magic, as does wiggling back and forth.

And patience.

Steve
 
airguy said:
There is a difference between standard Phillips bits and the JIC Phillips bit - the standard Phillips is designed to "cam out" if the torque is too high, and ends up rounding off the corners on the screw head. Get a real JIC phillips bit, they fit exactly the contour of the screw head. It will either come out, or shear off. If you are already in the situation to consider using an EZ-out, this is your best bet. An impact driver, as mentioned earlier, works best in this situation
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ref=sr_1_5_pp

That text above is a link to the JIC screwdirver on Amazon. I think its the one in my tool box.

The Standard phillips screwdriver is fabricated for production and so the designers wanted it to strip out at a certain torque. The JIC bits design (japan origin) is different and are a game changer. I dont even want to use my standard screwdriver anymore. It's my go to screwdriver now.
 
Gentlemen, I greatly appreciate all your input. I have ordered the suggested tools and will begin this task as soon as they arrive. 8MikeXray......... are you suggesting the Z bracket bolts will present a BIGGER challenge ? ................. Ayee I can't wait
 
screw knocker and a rivet gun or a Johnson bar/El brutus Screw Extractor. https://www.autotoolworld.com/Brown...WGX4gH6Kkj7GCzB1CCbeRvCRo_yrCfTgaAnzgEALw_wcB


I worked as an A&P for over 25 years. The screw knocker and a rivet gun works well. So does the Johnson bar/El Brutus. I understand that Delta airlines made a work-aid based upon the El Brutus design that was several feet long for removing screws in the floor of the cargo compartment. They’d remove one screw in the middle of the panel and have someone step on the end (tremendous leverage) and start cracking them loose As they worked their way out from the middle.
 
Mark Cigal said:
Gentlemen, I greatly appreciate all your input. I have ordered the suggested tools and will begin this task as soon as they arrive. 8MikeXray......... are you suggesting the Z bracket bolts will present a BIGGER challenge ? ................. Ayee I can't wait
Click to expand...
Yes go to harbor freight and buy the super expensive stubby mini 1/4 ratchet called Icon tool brand. It’s their knock off of snap on but real nice for the money. Then use a 1/4 shaft socket to make it as small of a package as possible. That’s the most efficient way to get at those Z bracket bolts. I’ve pulled my tank twice now. Not fun.
 
Highly recommend Aerokroil for stubborn bolts. We use it at Tinker on turbine engines. We had one that the bolts were really stuck and we sprayed them down with it and let it sit for a while and they came right off.
 
Hi Mark,

I have always had the best results with 50/50 mix of acetone and ATF Apply to the screws once they are stripped of paint. If any paint remains, it’s next to impossible to get a lubricant on the seat of the screw where it really matters. I have done this multiple times on certified Aircraft with no issues, removing the screws once they are clean and lubricated. The Z bracket hardware should not be as difficult to remove/ (no paint) provided you have a small enough ratchet to reach in there and back them off.

Mike Cingari
 
Majorpayne317641 said:
Yes go to harbor freight and buy the super expensive stubby mini 1/4 ratchet called Icon tool brand. It’s their knock off of snap on but real nice for the money. Then use a 1/4 shaft socket to make it as small of a package as possible. That’s the most efficient way to get at those Z bracket bolts. I’ve pulled my tank twice now. Not fun.
Click to expand...
Pick your favorite brand 1/4 drive right angle mini battery ratchet with a 3/8 deep socket.
That’ll get 95% of the z bracket bolts out in about 3 seconds each if the pushrod tube is out.
 
Richard Connell said:
Pick your favorite brand 1/4 drive right angle mini battery ratchet with a 3/8 deep socket.
That’ll get 95% of the z bracket bolts out in about 3 seconds each if the pushrod tube is out.
Click to expand...
Which one? I found an 1/4in air ratchet to be the smallest but it does come with the air hose penalty. My Milwaukee electric ratchet is a little too big for that space.

I also wanted to avoid unbolting the control tube.
 
You'll end up using a couple tools on the Z-bracket bolts, and both hands as well. You'll want a short socket, a long socket, and a short extension for the ratchet. Interchange as necessary.

The first time I pulled a tank, it took nearly 3 hours and I used up most of my "working words". Now I can do it in about 45 minutes.
 
Majorpayne317641 said:
Which one? I found an 1/4in air ratchet to be the smallest but it does come with the air hose penalty. My Milwaukee electric ratchet is a little too big for that space.

I also wanted to avoid unbolting the control tube.
Click to expand...
It’s a dewalt DCF504GG1

I think there’s no right or wrong approach here TBH. Everyone has different mobility/flexibility/hand sizes.
I’ve done it pushrod in and pushrod out. I’d say for me it’s a wash time wise by the time you pull the seats/seat pan/wingtip/pushrod. But I probably curse less and finish with fewer injuries pushrod out. I don’t plan to collect any more data :)

The real cursing is comes from getting the 3 bolts back in. Awl, bolt, washer all in one hand like chopsticks working two bays down from the access panel is a test of character!
 
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