Fun comes to a halt–Fuel Tank Leak

[Michael Burbidge]

I'm so bummed out.

I discovered this evening that fuel has been leaking from the cover on the fuselage end of the tank. I guess that's what I get for deviating from the plans. I used tank sealer instead of the supplied gasket. I had read that people had problems with the gasket.

It appears that the tank sealant is just lifting away from the aluminum on the tank. I checked the other side and no leaks there.

Here's a couple of pictures.





I have a few questions.

? Is there a chance I can remove the cover, and fuel sender without removing the tank?

? What tricks are there to removing the bolts from the z-brackets? Special tools that help, etc.?

? The tank is full. What precautions need I take to empty the tank? I plan on draining the fuel into 5 gallons fuels containers from the fuel drain.

? I assume it is best to remove the bolts from the z-bracket first, followed by the screws into the spar. Is that correct?

Any other suggestions you have would be greatly appreciated!

Thanks,
Michael-

[Dbro172]

I had similar issue, found it during tank calibration. I'd get it off the plane and onto a work bench. Removing the tanks is tedious but in reality can be done in only about a half hour. I used a pneumatic ratchet on the tank bolts, it's a pain working thought access panels but better than the one click shuffle you'll have to do with a manual ratchet.

Drain the tank into cans like you suggested. Make sure you find the leak before taking that access plate off. It might be the end rib or something and draining across the plate. Fuel leaks easier than water. I put a couple gallons of fuel back in the tank and pressurized it (slightly) to find my leak that was not detectable with air or water.

Polygone gel from Vans cleans that proseal off like nothing. Get everything cleaned up, re scuffed, acetoned and seal it back up. I didn't use the gaskets either time.

Cheer up! This is only a morning job... Few hours tops. Your forearms will be beat up though!

[crabandy]

For about $15 I went to the hardware store and bought a brass nipple (NPT) to screw into the fuel quick drain hole, a couple feet of fuel hose and a brass valve to make fuel draining controllable. I was surprised at how little fuel is spilled when I remove the quick drain and screw in my drain valve (I've already used it 3 times And working on a 4th), the valve makes it easy to swap gas cans etc.

[scsmith]

Although it is not too tough to do, as others have pointed out, you do NOT need to remove the tank.
On my RV-8 I have removed the cover and removed and replaced the fuel sender on the plane.

To get the phillips head screws out, use a short phillips insert like what you would put in a drill or electric screw driver. To turn it, get a 1/4" ratcheting box wrench, which will fit on the hex side of the insert, and then you can ratchet out the screws. You might need to make a block of wood the right width to wedge against the back side of the insert to keep the phillips from coming out of the screw when you turn it. It also helps to use some tape to wrap around the insert and the ratchet to try to keep the insert from falling out of the ratchet.

When I re-assembled, I used socket-head cap screws so "next time" I can use an Allen wrench to get them out.

Also, many folks have recommended using Proseal instead of the cork gasket.

*** BUT, THERE IS A BETTER WAY ***

Use the cork gasket, and use a gasket sealant called Permatex High-Tack. Or a very similar product, Permatex Aviation Form-a-Gasket.
Either of these products is a thick brown syrup that you brush onto the gasket (both sides). I have used this for years on cars and airplanes and anything else where fuel or oil needs to be sealed with a gasket. I have NEVER had it let me down, EVER. And the best part, if you ever need to take it apart, it is pretty easy. Unlike using pro-seal, which will be very difficult to ever disassemble.

[DanH]

A de-fueling operation should include grounding, as fuel can build a static charge as it falls from the drain to a container. It's easy to be safe; all you need is two lengths of wire and two alligator clips. One alligator attaches to the airframe. From it run a short wire to the fuel container; simply strip the end and submerge it in the fuel. A longer wire runs from the same alligator to an earth ground; a hanger door track is good. Everything remains at the same potential.
The fitting, valve, and hose Andy described is fine idea. Use the same two wires, or a graphite-lined fuel hose and make sure the end is down in the fuel.

[wilddog]

Remove the tank, it's not hard to do. I don't think you will ever get the cover free of the Proseal working with it in place. You will need heat from a hair dryer or heat gun and some plastic scrapers and wood wedges to work it free. I didn't try it but the stuff that dissolves Proseal might help if you use it around the edges of the cover. My cover had been sealed about 15 yrs ago and the Proseal was a bear to get lose. Mine was not leaking but had slosh that needed to be removed.

[Dean Pichon]

I had the same problem last month with my -4. I had drained a tank to calibrate a new fuel gage during annual. During the week the tank was empty, the cork gasket dried out and it leaked horribly when I refilled the tank.

Originally, the I built the tank using cork gaskets and Permatex gasket material. I believe that was a mistake. I pulled the tank, cleaned it up and replaced the access panel with polysulfide access door sealant. It is the same stuff used for building tanks, but it has less adhesion, so you can more easily remove it if necessary. The stuff I used came from here:

http://www.skygeek.com/flamemaster-c...lant-pint.html

Good luck,

[Vlad]

Michael keep the fun going while removing the tank it's an easy fix. Exercise the privilege of your wet FAA repairman certificate. All above advice is great make sure you unscrew ALL bolts from z brackets. Report back here

[pa38112]

Easy enough to do without removing the tank. This Craftman screwdriver ( http://c.shld.net/rpx/i/s/i/spin/ima...arpen=1&qlt=85 ) will make it SOOOOO much easier: It accepts a 1/8" socket for leverage and has great grip. - Replace the screws with socket head cap screws so that you can put a socket on them in the future.
You want to be very careful not to bend the cover plate or the tank wall by prying off the old lid/sealant. I used a thin piece of sheet metal to make a 2" wide X 9" long scraper with rounded edges that you can work between the two to cut the sealant. If you keep it well lubricated with (Cant remember if I used MEK or Acetone ) It will very slowly slice through the sealant like butter.
Once the cover is off you can use scotch bright soaked with the same solvent to clean up the surface.

I think it took me about 1.5 hrs to get the old one off, 1 hr to clean up all of the parts for re-assembly, and 1 hr to put it all back together. I think removing the tank would have taken longer, and risked scratching the paint.

Be careful not to get the new sealant on your float when you go back in, and if you have not already done the SB on the fitting, this is a good time to do it.

[sailvi767]

I have a bad fuel sender in the RV6. I was told the tank has to come out to replace the senior. Can the sendor be removed and replaced on a six without pulling the tank?

George