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I purchased my Coupe at a bargain basement price because it had been declared, in the log books during an annual inspection, that it was "not airworthy because of fuel system contamination". This contamination was small brown flakes or particles that had completely contaminated the entire system. They plugged the primer, gascolator and fuel pump. Some even got past the gascolator and found their way into the Carb. I removed the fuel tanks and opened up the main tanks and found someone in the past had sloshed the entire inside of the tanks with some material that was dark brown and flaking off in large amounts. I used paint stripper to remove all of it from the mains and used several gallons of MEK to remove it from the header tank. Had to replace all of the fuel lines, overhaul the primer, carbureter, gascolator and fuel pump to ensure that all of it had been removed. I reriveted the tanks using Pro-seal as the seam sealer. The inside of the tanks were alodined also. Alodine when applied is very very thin and will not flake off. It is a chemical treatment for aluminum and is very thin. I read the service bulletins somewhat differently than some on this issue. I take it to mean that EC-776 and 570 were approved as SEAM sealers. Pour it in, rotate the tank until all seams had been treated by allowing the sealer to run along the seam then pour out the remainder. I do not take it to mean coat the entire interior surface of the tank. My IA and I were able to drill out the 200+ rivets in each tank one Saturday. I spent a couple of days cleaning the interior of the sloshing material, removing the filler and gauge fittings etc. We then re-riveted the tanks together using Pro-Seal between the sealing surfaces and around the rivet heads and tails. I also used Pro-seal to seal between the fittings and tank as they were riveted back in. Why use Pro-Seal? EC-776 and EC570 are no longer manufactured and when asked, the FSDO said that Pro-Seal would be acceptable. It is used in everything from Production military, civil, space craft, General Aviation and experimental aircraft to seal fuel tanks that use some very exotic fuels. We even use it in the missile tube on board submarines. Only thing about it is that it will absolutely get into and onto anything within six feet of an open container of Pro-Seal. If you use it, wear disposable clothes, gloves and keep a container of MEK or such nearby to drop the contaminated cleco's and riveting tools into so it will not glue them into one piece if it dries on them. After it dries, I know of nothing that will soften it or dissolve it. By the way, the only corrosion that I found in the tanks was on the rivets holding the drain fitting on the bottom of the tanks. One rivet was entirely eaten away and had been replaced by a pop rivet. Two or three others were almost gone. Rich Blair N99997 & N23287 Kingsland, Ga ============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm
