R

Ron B.

Well Known Member
I had a seeping fuel drain and replaced with what I had purposely purchased o-ring. Installed the valve and let sit overnight before refilling. Upon refilling, fuel was dripping out from the get go. Draining what little fuel I had poured in and removed the valve. No o-ring , wow. Thought it must have broken off a fell out before I installed the valve. No big deal. Installed another one and repeated the process. This time no leaks , good. Problem solved, but not so fast . This morning ( next day after refueling) what a smell in the hangar. Fuel was dripping out rapidly. Re-drained the tank once more and the o-ring is swelled and broken. This one came out of the tank with the valve. Obviously I received the wrong type of o-rings .
My concern is where is the first one I replaced. I used a Mr. funnel with a screen . It must still be in the tanks . Any ideas how to get it out . RV-14 tank. Thanks
 
With one of the smaller-head horoscopes available you can look up into an empty tank through the drain hole (been there, done that looking at my vent line B-nut) and perhaps see if it is in fact in there. Then try to flush it out with fuel poured through over and over.
 
Bill Boyd said:
With one of the smaller-head horoscopes available you can look up into an empty tank through the drain hole (been there, done that looking at my vent line B-nut) and perhaps see if it is in fact in there. Then try to flush it out with fuel poured through over and over.
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I’ve tried borescopes before for other purposes. Never been successful yet seeing what I was looking for.
Thanks
 
Well, if a borescope hasn't been successful, maybe find a friend with a different scope and/or a different technique. That would seem to be the easiest and best approach. But without that approach, it kinda narrows down your options. You could open the tank by removing the fuel sender plate, but that's a bit invasive and you still may need a borescope...or possibly mirrors and flashlights. Bill also suggested flushing the tank out, so you could give that a try. Maybe raise the tail and pour a little fuel at a time into the tank and hope you catch the remains of the errant O-ring with "Mr. Funnel" and the screen.

An unsolicited suggestion: order a complete fuel drain that has the correct O-ring from Aircraft Spruce (or whomever) and have it ready to install. It's good to have a complete spare on hand for a quick change when it's needed. Either you or a flying buddy will be glad you have it one day. They're not very expensive and you can swap them out without draining a tank.
 
I'm going to offer thoughts that you might not find comfortable or wish to pursue.

Do nothing.

You do have a screen on the fuel pickup, right? Do you have any filtration in the fuel system? Isn't it likely the remnants of the o-ring...IF there are any remnants (it may be dissolved now....) would be caught by the screen or filter?

Before doing something drastic such as opening a perfectly good fuel tank you could install a filter in the wing root to catch anything.

Do all takeoffs and landings on the other tank until you are confident the o-ring is history. Yes, I realize this might be outside your comfort zone, just offering food for thought.
 
Or...take another o-ring of the exact same material, and put it into a jar of fuel (whatever you were using...Avgas, Mogas, whatever) and see what happens.
 
RV7A Flyer said:
Or...take another o-ring of the exact same material, and put it into a jar of fuel (whatever you were using...Avgas, Mogas, whatever) and see what happens.
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Ron
You didn"t say where you purchased but Vans stocks them. 1/4"od .125 ID. Part# CAV-110 O-Ring. I just ordered 2 last week.
Arnie
 
Spruce has them.. size 006. They have the fuel resistant ones, but say they aren’t resistant to automotive fuel. If using car gas, perhaps the Viton ones are better. I wouldn’t worry about the remaining Orings in the tank, the finger screen should block it without clogging.. you could try letting the fuel tank drain completely thought the sump and see if it comes out. Then once empty, go looking around with the borescope..
 
My current boroscope has a side camera and would (I believe) easily spot an object lying in the inboard bay from the fuel drain hole.

Agree yours is likely dissolved by now, otherwise easily catchable in your fuel straining and filtration system before it could do any harm.
 
I have an o-ring sitting in a pan of fuel to see if it will dissolve.
Thanks for all the replies.
 
Ron B. said:
I have an o-ring sitting in a pan of fuel to see if it will dissolve.
Thanks for all the replies.
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Great idea. I have a quart jar of Costco premium sitting in my hangar to show people that Ethanol does "not" settle out of the fuel like some say. It's been there for over two years all sealed up. As for the O-ring test, I've done just that. But I made sure it was in a sealed container because I don't want the effort ruined by evaporation helping the O-ring survive.
On another note: I have standard Van's O-rings on my drains and they have never given me any trouble for three years of using Costco premium
But my luck varies Fixit
 
Taltruda said:
Spruce has them.. size 006. They have the fuel resistant ones, but say they aren’t resistant to automotive fuel. If using car gas, perhaps the Viton ones are better. I wouldn’t worry about the remaining Orings in the tank, the finger screen should block it without clogging.. you could try letting the fuel tank drain completely thought the sump and see if it comes out. Then once empty, go looking around with the borescope..
Click to expand...
I use the ones from Spruce with both 100LL and auto fuel and have not had a problem with them. I also agree have an extra drain valve to be able to swap out when one starts to leak. You can also swap it with full tanks you’ll only lose a very small amount of fuel. Then you can replace the oring and make that valve your new spare.
 
You may not like this idea, but it's not that hard to remove the fuel sender (can do it with the wing attached). That will give you clear access with a borescope to the bottom of the tank and the fuel pick-up tube. I had to replace a sender once that was prosealed in. Used a plastic chisel to pry it off.
 
These are the o-rings I had purchased for the fuel drains. Don’t recall where I purchased them. Also don’t know if I ordered the wrong ones or was supplied with the wrong ones.
 

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