Fuel valve leak problem on JAL 787 cause found-

[The Inspector]

The Japanese Civil Aviation Authority said the cause of the leaky fuel shutoff valve on the same 787 that was grounded in Boston with a battery issue was caused by improper applicaton of a dilectric paint by its Japanese manufacturer, which caused the paint to peel away as the valve moved and paint debris jammed the positon switch so it indicated 'closed' when it was about half closed.

The first sets of wings shipped in from Kawasaki had sealant that was about half mixed and sort of rolled into long TOOTSIE ROLL ropes and kind of packed against the edges of the stringers (instead of fay sealed between the parts) which could be pulled up in long sections due to no bond between the parts and caused serious and long hours of rework @ Everett, lack of previous experience with those sorts of processes, and they 'own' and take responsibility for the QC on their parts.

[CAPFlyer]

Is this internal or external to the valve? I ask because I had a couple of 737 fuel manifolds that did that externally and had to be replaced because of concern for contamination.

[The Inspector]

Is this internal or external to the valve? I ask because I had a couple of 737 fuel manifolds that did that externally and had to be replaced because of concern for contamination.

I don't know for certain since the particular valve has never been shown in the press, but since the leak was spotted on the ramp and 'fixed' without defueling I'd guess it's externally mounted.
Are you talking about the spar shutoff valves or the refuelling manifold in the right wing leading edge? If the spill prevent flap works correctly you should get just under a quart of spilled fuel (bring a spill sock) when you pull the spar shut off valve, and a 'droozle' when you pull the fueling point valves.

[CAPFlyer]

The problem was that on the new manifold there is a portion of the pivot that is exposed externally to allow you to verify movement of the valve. Because of the paint problem, there was concern it might get into that area and cause it to not operate properly. I had my doubts knowing how heavy the spring was holding them to the closed position, but then again, I'm not a mechanic, so I didn't question it. My bigger concern personally was that the new VTO system being used was very unreliable and on multiple occasions shut off the wing tank over 500 pounds prior to where it should have and I verified with the mag sticks that there was still plenty of room left in the tank for expansion. When I went back to fueling in 2009, I noticed this to no longer be an issue, so I'm guessing that Boeing fixed it at some point. The worst case I had was a brand new Continental 737-800 (their 3rd ETOPS bird) came in and the left tank VTO'd at 7800 pounds while the right wing VTO'd at 8600 pounds.

[The Inspector]

I believe the VTO system and software got a serious shake up with the 7-900's since it was pretty much what was installed in the original 100/200's in the 70's which were designed for 450 mile lob shots @ 22c a gallon refined stove oil. The days of watching a backlit 737-100 departing and hearing some wag comment on tower freq 'nice punt' are gone.