Fuel valve

[8224]

I am restoring ‘47 140 and the old brass three way valve was still installed. I had to remove and repair the right gear “box” so the valve was removed along with all the other necessary skins. What is the most popular and approved valve to replace the old one.
Steve Hawley #8224

[5557]

I'm in the process of replacing mine on my '46 120. It was leaky and I didn't want to try and rebuild it and go through the considerable effort to reinstall it only to find it might have to come out again. I gave due regard to Victor Grahn's excellent article in the Newsletter on rebuilding the old valve, but I decided to buy the Univair PMA replacement, also a Piper part, but approved for the Cessna 120-140. Comes as a kit with a new valve handle and cap screws for attaching it to the mounting bracket. The valve body is machined from a robust aluminum billet, comes with an anodized finish and is quite stout. It fits the original mounting holes on the mounting bracket. It has ball bearing internal detents with very nice, positive detenting action. If you can leave the original AN823-6D 45-deg elbow fittings in place on your old valve as you remove it, they can be a useful reference in helping you tighten/position new elbows (not included in the Univair kit) to the correct orientation on the new valve before inserting it into position, to line up with the B-nuts on your fuel line connections. This will be important for anyone doing this solely through the gearbox top access holes (both landing gear still in place), as it requires "working blind" in very cramped space. I also found it immensely helpful to temporarily disconnect the left and right fuel feed lines from the line-splice unions easily accessible beneath the door sills to loosen the left and right feed line segments near the valve so as to facilitate line-up and initial threading of the B-nuts onto the elbows. Again, important for working blind and to minimize the chances of cross-threading connections from the B-nuts to the elbows. I'm using Permatex #56521 High Performance, fuel proof thread sealant (also not included in the kit). The Univair kit is pricey: $453.20, but the STC alternative from an alternative source is around $570, and you would have to file a 337 if you go that route. I'll let you know how my task turns out after the skin graft surgery to the backs of both hands and the paint on my shop wall stops peeling from my extreme shouting and profanity. Good luck.

[6298]

I just removed an original one, repaired it and put it back in. I can tell you that my wrists took about week and a half to heal.

[8233]

Curious question. On a 1946 C120 for example, is there a option/path to upgrading to a fuel selector that will also allow a "Both" setting so it can cross feed?

[6643]

In order to have a "both" position, the air spaces of the two tanks must be interconnected. The later tanks have this; the early ones do not. Without it you will not get even flow between the two tanks and could possibly even run out of gas with a full tank on one side.

[8233]

In order to have a "both" position, the air spaces of the two tanks must be interconnected. The later tanks have this; the early ones do not. Without it you will not get even flow between the two tanks and could possibly even run out of gas with a full tank on one side.

Makes sense, has anyone ever pursued a STC to make those changes to the earlier models?

[6643]

I don't think you'd need an STC, just use all the correct parts.

One reason not to do it: you need 1/4 tank in at least one tank to take off. If you have 3/16 of a tank in each tank you've got more than 1/4 tank (3/8) on board but cannot take off...

[8233]

I don't think you'd need an STC, just use all the correct parts.

One reason not to do it: you need 1/4 tank in at least one tank to take off. If you have 3/16 of a tank in each tank you've got more than 1/4 tank (3/8) on board but cannot take off...

Interesting. I assume that's an existing challenge for the later models as well?

[6643]

Interesting. I assume that's an existing challenge for the later models as well?

Yeah. Of course, you can use it like a left-right valve. Seems sort of like a solution in search of a problem...