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Fuel selector o-ring

M

MarkCFI

Well Known Member
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I’m at the hangar with my fuel selector valve apart. It is one of the older 3 port with a brass cone.

I cleaned, lubed and reassembled but it only had a single o-ring to replace. It appears the at some point an aluminum washer was used as a gasket for the cap.

Should I leave that or replace with an o-ring?

Thanks.
 
I believe the o ring is a -11 and yes the aluminum washer is correct. What are you lubricating it with? I used fuel lube but when it gets cold, it’s almost impossible to move. Imagine the surprise when I was at 15,500, I drained a tank and went to change tanks and the selector wouldn’t move! I’m going to wash that out and use kryox grease that someone recommended.
 

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Thank you for the diagram. I didn’t have that one and it shows exactly what I have.

I am using Krytox as well. I assembled it and it was smooth as silk but the aluminum washer bugged me so I disassembled it again.

I guess I should have left well enough alone.

Thanks again for the quick response
 
Taltruda said:
I believe the o ring is a -11 and yes the aluminum washer is correct. What are you lubricating it with? I used fuel lube but when it gets cold, it’s almost impossible to move. Imagine the surprise when I was at 15,500, I drained a tank and went to change tanks and the selector wouldn’t move! I’m going to wash that out and use kryox grease that someone recommended.
Click to expand...
What's a good source for these parts?
I know the O-ring is standard, but for some of the other items that wear (position washer)
 
1994 RV6 Fuel selector valve,

The fuel selector valve was getting very difficult to turn so today I De-Fueled into 5 gallon fuel jugs. Removed the valve & took it completely apart. I polished the brass cone & put it back together using a new MS29513-011 O-Ring inside the cap; lightly lubed with fuel lube and Re-installed. Re-Fueled and it works like new.
I’ll try Krytox next time.
 
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Tracer 10 said:
The fuel selector valve was getting very difficult to turn so today I De-Fueled into 5 gallon fuel jugs. Removed the valve & took it completely apart. I polished the brass cone & put it back together using a new MS29513-011 O-Ring inside the cap; lightly lubed with fuel lube and Re-installed. Re-Fueled and it works like new.
I’ll try Krytox next time.
Click to expand...

I know the feeling how sweet it turns! However, up at altitude or later this winter at any altitude, it’ll feel like you are about to snap that handle trying to turn it. I would get that fuel lube out of there sooner than later..
 
Tracer 10 said:
The fuel selector valve was getting very difficult to turn so today I De-Fueled into 5 gallon fuel jugs. Removed the valve & took it completely apart. I polished the brass cone & put it back together using a new MS29513-011 O-Ring inside the cap; lightly lubed with fuel lube and Re-installed. Re-Fueled and it works like new.
I’ll try Krytox next time.
Click to expand...

The valve does not need to be removed to service. Back off the screw and pull up on the handle to release from the taper. Un screw the cap and lift the assembly out.
 
Taltruda said:
I know the feeling how sweet it turns! However, up at altitude or later this winter at any altitude, it’ll feel like you are about to snap that handle trying to turn it. I would get that fuel lube out of there sooner than later..
Click to expand...

If this ever happens, reach under the handle with two fingers and pull up. It will cause the cone to lift and release so it can be turned....Van's valve only.

B.T.W.... if you still have the old valve with a brass cone, replace with the new style valve with nylon cone..... way better.
 
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I have the older valve in my 7A. It reached a point years ago that it became difficult to switch tanks almost sticking. All I did was to squirt a little WD 40, (because it's lite and will run down), on the stem and after it worked it's way down... problem solved. I do that about every 6 months or so. Still works great. Never have had it apart. I also lubricate the fuel caps the same way. Keeps everything working great with no sticking or stiffness.
 
Thread update for anyone rebuilding these valves.
The diagram above has the crush gasket labeled as Univair 752-822. That's an incorrect part and likely carried over from one of the Piper Forums. (Although the online catalog photo looks like it might be the right thing.) The rest of the parts callouts are correct.

The Piper part is 752-692. If anyone has a spec on those, it'd be helpful. I can't find the things anywhere.
 
Martin Hill said:
Thread update for anyone rebuilding these valves.
The diagram above has the crush gasket labeled as Univair 752-822. That's an incorrect part and likely carried over from one of the Piper Forums. (Although the online catalog photo looks like it might be the right thing.) The rest of the parts callouts are correct.

The Piper part is 752-692. If anyone has a spec on those, it'd be helpful. I can't find the things anywhere.
Click to expand...
Did you ever find the correct part of substitute.

I heard people trying an AN900 crush washer.
 
Jav8or said:
Did you ever find the correct part of substitute.

I heard people trying an AN900 crush washer.
Click to expand...
I did not find the right part for the crush washer. Swapping o rings and the detent ring and re using the crush washer worked okay but the detent ring has worn quickly. Since there’s better valves available, I’ll replace at annual.
 
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