Fuel Tank Control valve

[Harry Moon]

Any body know of a method to rebuild that valve. Several times I have had it leak, suck air and cut off the fuel, they don't seem to last long, any tips, rebuilders. I tried to see if there was already a thread on it but can't find one if there is.

[Mike Cecil]

Is this the CMP fuel tank changeover tap in the cab floor you are seeking advice on?

The one I had in my first Ford CMP was a tapered brass affair with an 'o' ring at the top. I lapped the tapered surfaces in with valve grinding paste to ensure as perfect a seat between the two surfaces as I could, and used a modern O ring seal. I checked that the lapping in was complete by using bearing blue to see that there were no gaps in the seating between the two surfaces. Took ages to complete the process.

Worked fine: very, very minor weeping but no air suction.

Mike

[Harry Moon]

I was thinking along those lines and as it happens I have some lapping compound.

[Lynn Eades]

Jeweller's rouge is apparently the stuff to use. Valve grinding paste is probably a bit on the course side. The fit needs to be air tight or your pump will likely suck air. Some taps have no "o"ring and so the interference is more important. Once done be sure to thoroughly clean it.
Another thing you could use is cutting compound.

[Mike Cecil]

Lynn, you've jogged my memory .... I started with the coarse valve grinding paste, graduated to the very fine VG paste and finished with Al-oxide powder compliments of the Earth Sciences Department at Monash University - the stuff we used to use for the final grinding of rock specimens mounted on glass slides.

Sorry Harry to have neglected to give you the full picture - it was 40 years ago! I'm sure jewellers rouge will work just as well as Al-oxide (if it's not the same thing with a fancier name) I think I also replaced the little tensioning spring at the bottom with a new one.

Mike

[Harry Moon]

T hanks guys, best place on the web and Ill post some pics in the near future of Frankenstien, he passed his Mechanical this week and waiting for the Vintage plates.

[Phil Waterman]

Hi Harry

Check the little spring on the bottom that was the culprit on one of my fuel selector valves, it was brass and had broken so it was not holding the center down tight.

Cheers Phil