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Newbie Proseal Question

Doug Rohrer

Well Known Member
I bought a project RV-9 with tanks already built. They were built before the SB 06-2-23 came out about safety wiring the fuel pick up tube to prevent the nut from coming loose. Of course, this SB was not done, so I get to do it. The tanks are not on the plane. I tried to remove the fuel sending unit, but it is Prosealed in and I can't even get a razor blade to go into the joint to break it loose. I suspect I can get the cover plate off, as the cork gasket will probably tear. Any advice on how to get the sender unit out? Heat? MEK? Can I remove the cover plate with the sender still sealed in? This stuff is tough!!!
 
Yes, remove the entire cover plate with the sender installed.
Clean and reinstall the cover plate with proseal only. The cork gasket will eventually absorb fuel and begin to leak.
 
Doug, you can also order a container of Polygone from Spruce. It’s the jelly that is designed to break down Proseal. But yes, remove the whole plate with the sender. I mention Polygone because, if it was done remotely right, the cork would’ve also been Prosealed,along with the attach screws.
 
Heat gun

Slowly apply heat with a heat gun and work the cover off starting with a razor or exacto type blade. I've found that the heat gun works best. Clean it by scraping and rubbing with a small brush on all the mating surfaces. Take your time though trying not to bend it all up.
 
I used a 1 1/2 inch putty knife and a safety razor. Once the cover is off, be sure to clean all the remaining cork and proseal off all surfaces and vacuum out all debris. Re-install cover with just sealant, no gasket. I used a low adhesion fuel tank sealant (I bought from Sky-Geek.com) in case I had to remove the cover again some day. No leaks.

Bevan
 
Guitar string

Slowly apply heat with a heat gun and work the cover off starting with a razor or exacto type blade. I've found that the heat gun works best. Clean it by scraping and rubbing with a small brush on all the mating surfaces. Take your time though trying not to bend it all up.

Find a friend musician and ask for the smallest string. Wrap the ends around two dowel rods. When the sealant is softened with heat, drag the guitar string through to break the seal.
 
Wow! There must be a lot of you guys cruising VAF on your day off! Lots of good answers. I dug around some more in the files and folders I got with the project and found a copy of the SB with notations the fix was made. It turns out the tanks were built in 2014/2015, well after the SB was out. This project went through three other owners before I got it, so the history is a little murky. I am glad all I did was remove the sender screws. I can just reseal them and put them back in. Thanks for all the great responses. I especially like the guitar string solution.
 
Good call to do this SB...

I was recently the witness of a friends RV-4 that had not had the SB done, and the pickup line came off in flight..fortunately, he was high and had time to manage the situation, RTB and land fine. During our troubleshooting, the aircraft ran fine with on the ground (tail low), but as I raised the tail to level flight attitude with the electric boost pump running, it cavitated. This situation could have been very bad! There was no warning whatsoever, and I must assume fuel pick-up was feeding normal until the "B"nut had actually came completely off, as we found the pick-up line off after opening the tank.
 
Van's SB claims an incident like this is what triggered the fix in the first place. I can imagine it would be hard to diagnose at first. Even with the tube completely off, I believe the engine would get fuel through the open fitting with a full tank until the level got low enough to uncover the fitting. It's a good thing these airplanes have a spare fuel tank on board!
 
Confirm the anti rotation bracket is installed before closing the tank..This aircraft fed fuel fine until the level in the tank reached 7 gallons remaining.....
 
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I used a heat gun and a 1/5" putty knife that I sharpened a little bit.

If I had heard of the Polygone stuff I would have used that too.
 
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