Clogged water drain line from fuel cap area
 

Is there an easy (read: inexpensive) way to clear a clog in a water drain line from the fuel cap area? I seem to remember blowing moderate-pressure air with a compressor from the drain end on the underside of the wing, but I'm concerned about causing damage. What about, once it's been dry for days, using a dropper to put some Drano down the tube? Any thoughts?

Ernie

I haven't tried this, but how about putting a little water in the line to soften the clog and use a piece of flexible plastic, such as a long thin tye-wrap to push the clog out of the line. You may have to do this from both ends of the line.

It's a pretty small hole, Jim. And it meanders inside the wing, so it's long, maybe 2 feet. That thin a tye-wrap probably won't be long enough. What about a thin solid copper wire, like the uninsulated ground wire in 14/2 Romex house wire? Also, you have any concerns about blowing it from the bottom or Drano?

Regards to you and Jenny.

Ernie

We blew them out from the cap end. I blew them while dad monitored the exit hole. Clog is gone

Don't Use Drano
 

Ernie:

Google Drano and Aluminum. You won't want to get Drano anywhere near your aircraft. Drano and water will cause an extreme reaction with aluminum.

Ernie
The tube is not that long. Maybe 12 inches. The tube passes through the tank out the bottom so only as deep as the tank or wing. The idea that Jim suggested will work. Add the water from the fuel service cap and allow the water to soften the contaminate. Then use the zip tie, wire, plastic weed whipper line or similar to push the junk loose. Flush with water or stoodard solvent (mineral spirits). You may want to make up some plugs with flags to keep the critters from going up into the tube.

Drano is very corrosive to aluminum. I don't think it would help anymore than water either. Remember folks to practice checking the free flow of these drains when servicing with fuel. Make sure you see the fuel visually drain out the bottom of the wing. If you have any doubts check it out. If the tube corrodes because of plugs the water from the top of your wing will find it's way into your fuel tank. This has caused a crash of one Skymaster that I know of. Luckly they all are still alive.

I'm with Frank on this one. Please do not use anything corrosive or anything sharp or harder than the drain line to clean out an obstruction.

A short blast of compressed air is more than adequate to remove whatever is causing the back up. You dont even have to mop the water from the cap well, the hydraulic action of the air pushing on the water helps to remove the clog.

If you use a wire, it will gouge the line at a bend.

The aux tank drain line is fairly long, as it runs from the cap to the leading edge of the inboard flap segment, and it has at least one 90 degree bend in it.

Thanks to all of you for your ideas.

Ernie