The dreaded drip

[Neal]

I've been fighting this issue since bringing home the new FX-3, at times the aft fuel drain drips and won't seal. I've tried running quite a bit of fuel through it, snapping it from open to closed, twisting it, staring at it, nothing works. I reached out to CubCrafters and apparently these things are prone to this so I ordered two more, one for replacement and one for a spare which apparently is recommended to have. I also learned about these from my fellow cub owner @turbopilot and everyone involved suspected either FOD or a failed o-ring.

Sadly there is no fuel shutoff for this line so I'll have to fly down the fuel to the lowest I'm comfortable with and drain the rest and then replace this contraption. I ordered two from CubCrafters at $30ea or you can order from Aircraft Spruce I realized after I ordered for about half that. Yaye me. I'm not quite sure what thread sealant to use but Pete gave me a sample of something called "EZ turn fuel lube" so I guess that's it. I also noticed on my CubCrafters' invoice the o-ring that this part takes and quite frankly that's all I probably need but if removing the drain why not replace it to be sure? But I ordered a few o-rings from Aircraft Spruce as I have hoarding issues and now I can add more spare parts to my toolbox

I'll keep you posted but here are links to parts should you ever need them.

MS29513-006 O-RING

MS29513 Fuel Resistant O-Rings | Aircraft Spruce

MS29513 Fuel Resistant O-Rings These MS29513 series O-rings are resistant to fuel and are ideal for applications such as fuel injection connections and primers. A small amount of fuel proof grease applied to these O-rings helps the...

www.aircraftspruce.com

FUEL DRAIN SAF-AIR CAV-160

Saf-Air CAV-160 Pushtype Fuel Drain Valve | Aircraft Spruce

Saf-Air CAV-160 Pushtype Fuel Drain Valve SAF-AIR push type fuel drain valves are close tolerance valves of simple design. These valves provide the most trouble free operation of any other line valves in the industry. SAF-AIR valves are man

www.aircraftspruce.com

EZ Turn Lubricant

EZ Turn Lubricant | Aircraft Spruce

EZ Turn Lubricant EZ Turn is a specialty lubricant/sealant used for fuel and oil line valves & is resistant to high temps. Especially effective where high octane fuels and aromatics are present. EZ Turn is also e...

www.aircraftspruce.com

 

[Cubonaut875]

I guess I need to put a drip pan under the drain as my hangar is carpeted. Good heads up on that!

 

[Neal]

It shouldn't drip, if it does it needs to be fixed. Just something to watch for.

 

[Cubonaut875]

With my carpet I would not know if it had a slow drip or not. A good thing to check.

 

[Waldom]

No need to drain the fuel system when repairing or changing a drain valve. Just get a correctly threaded pipe plug from the local hardware store to screw in to the fitting while you inspect and repair the valve. Place a drain pan underneath the work area to catch what little fuel is spilled during the exchange. If you are concerned about the lead exposure from the 100LL fuel, pick up a box of rubber mechanic"s gloves at the auto parts store.

 

[Neal]

Interesting idea. I have a replacement fitting so it would be remove the old and get the new one immediately installed. I would prefer to install it dry but I guess it doesn't matter? I'll still get the fuel level low but maybe I don't need to worry about draining 10'ish gallons.

 

[Neal]

No need to drain the fuel system when repairing or changing a drain valve. Just get a correctly threaded pipe plug from the local hardware store to screw in to the fitting while you inspect and repair the valve. Place a drain pan underneath the work area to catch what little fuel is spilled during the exchange. If you are concerned about the lead exposure from the 100LL fuel, pick up a box of rubber mechanic"s gloves at the auto parts store.

Thank you for this great tip. Didn’t care to keep flying down fuel so today I decided to just get this done. Wore gloves and safety glasses. Removed old and replaced with new (prepped with the lube) and maybe lost 8oz of fuel. Super simple.

Done!!