Is it okay to cap off a wing tank sump?

Sinistar

Sinistar

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Brad
For a Cessna 182P 1972 (sorry no picture...yet)

During my preflight i always first: check both tank levels, sump both tanks, check oil and oil cap and then start the walkaround routine. Next, while walking around i noticed a small fuel puddle under the pilot side wing sump. I used the sump tester to excercise it up and down a few times and now its dripping much more slowly, maybe a drip per 5...10 minutes. The temp was about 4deg above freezing...doesnt seem like ice. It seems like the spring actuated whatever isnt coming back down perfectly straight or just not enough force or whatever gasket or seal must be going.

I want to cap it off to be 100 percent sure it wont leak while were away from the plane. As long as i sump before flight, i should also be able to fly with it capped off...right?

If anyone has had to cap theres off, do you have a recommendation for a plumbing style cap that would fit those outter threads? Im just thinking something i can hand tighten until i get it fixed...which will require a flight.
 
Ice crystals are common in cold fuel even as ambient rises above freezing. Add some isopropyl to that tank, wait a few minutes, and sump again. If it stops the seep you proved it was ice. If it doesn’t? Isopropyl won’t hurt anything and you need to get the sump drain replaced.
 
Stewartb said:
Ice crystals are common in cold fuel even as ambient rises above freezing. Add some isopropyl to that tank, wait a few minutes, and sump again. If it stops the seep you proved it was ice. If it doesn’t? Isopropyl won’t hurt anything and you need to get the sump drain replaced.
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Is okay to add isopropyl to fuel bladders?
 
This is a Cessna quick drain?
If so, I'd replace it.
 
It is in my Cessna. I think they recommend 1% by volume. That’s one 12oz bottle per 10 gallons but I’ve found one bottle works fine with 20 or more gallons. I just add 1 bottle per side and go, and I don’t sump wings in winter. I will sump the strainer if it was warmed by engine preheat. Better yet I try to pull the strainer after a flight so it’s good to go next time.
 
Tom-D said:
This is a Cessna quick drain?
If so, I'd replace it.
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But i dont know how, tank is full, dont want 37gals of fuel on the hangar floor and need to fly it to fix it. You stated the obvious..thx...but i need the leak stopped first.

Sorry, not sure if its a "quick drain"...ill try and find some web pics to verify.
 
I dont sump when its really cold...but today it was above freezing. Ill try some isopropyl but still might need a cap.
 
Im not worried about lost fuel on the ground. I just dont want to burn down the plane and hangar :eek:
 
If you have a blow dryer or other warm air heater that you think is safe to use you can point it at the drain and see it the drain seats as it warms. If it does it indicates water and isopropyl would be the answer so if it was me? I’d just do the isopropyl first.
 
Sinistar said:
But i dont know how, tank is full, dont want 37gals of fuel on the hangar floor and need to fly it to fix it. You stated the obvious..thx...but i need the leak stopped first.

Sorry, not sure if its a "quick drain"...ill try and find some web pics to verify.
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Fly the fuel out of that tank, (empty) switch to the other tank and land, then change that Quick drain.
 
Tom-D said:
Fly the fuel out of that tank, (empty) switch to the other tank and land, then change that Quick drain.
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okay...but what can i cap it with....until i can make that flight???
 
Stewartb said:
Don’t replace the drain until you rule out ice. It would waste time and money fixing something that isn’t broken.
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IF __ IF it is the standard Cessna quick drain, they are pretty ice proof.
 
Sinistar said:
okay...but what can i cap it with....until i can make that flight???
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one drip every 5 minutes? don't worry about it for 1 flight. pull it out start it and go fly the fuel out of the tank. all of it.
 
Stewartb said:
If you have a blow dryer or other warm air heater that you think is safe to use you can point it at the drain and see it the drain seats as it warms. If it does it indicates water and isopropyl would be the answer so if it was me? I’d just do the isopropyl first.
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Another good idea, thanks! Ill use a blow torch, that should be quicker...kidding:)

If that doesnt work: per Tom's earlier advice, ill go fly off 37 gallons off right now at night in IMC which should only take 4 hrs and requires running a tank dry at night...and im not instrument rated.....sorry @Tom-D I couldnt resist :)
 
Sinistar said:
Another good idea, thanks! Ill use a blow torch, that should be quicker...kidding:)

If that doesnt work: per Tom's earlier advice, ill go fly off 37 gallons off right now at night in IMC which should only take 4 hrs and requires running a tank dry at night...and im not instrument rated.....sorry @Tom-D I couldnt resist :)
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How many gas cans can you borrow?
 
Tom-D said:
How many gas cans can you borrow?
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Unfortunately, not 37gal worth. Id much rather put on a $1 cap so it wont drip...right now! Spin off said temporary cap off before the next flight, make sure no water, put cap back on, fly to mechanic and he'll fix it 17x faster than i ever could...without burning down a hangar with 10 planes in it...like i probably would.
 
valves_cessna.jpg mine looks like this one, has outter threads
 
Take a small fuel sample. Twist the sample nipple a few degrees. Sample again. Twist the sample nipple a few degrees. Sample again. Leak gone? You chased a microscopic dirt/sand/rust particle out of the sealing o-ring. Still there? Follow Tom's advice, run the tank dry and replace the o-ring.

Thankful to the Holy St. Potluck, our winter appears to be over. 60df and clear for the first time since November. Whuff. I've seen worse, but I've seen milder.


Jim
 
Mine looks like that as well. If you haven’t already, see if you can do a few full pumps up and down on it to clear any particle that might be trapped in there.
 
If you are messing around installing a plug into a drain with fuel in the tank, why not just install a new drain and be done? If you are truly worried about losing fuel, drain the tank.

PS Removing a drain with fuel in the tank sucks and sucks lots more when having to do it twice.
 
Maybe I should clarify. My wing fuel drain has outside threads. I figured I could maybe just find some plumbing-like cap (brass?) To lightly screw over it...a cap.

I never intended to remove a drain (with a near full tank) to install a temporary plug and then do it again to actually fix it.

It just seems like there must be a simple 1/2" threaded cap (okay, that was a guess on the thread size) I could find to screw over it until the mechanic fixes it. No leaks until it's fixed - check! Can be removed to sump - check!
 
I had a different style on my 182 that started leaking and we just replaced the o-ring and it worked great. I'm not sure what the entire drain costs but this option may be worth looking into.
 
MtnMarcus said:
I'm not sure what the entire drain costs but this option may be worth looking into.
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All things considered, they aren’t all that expensive compared to most airplane parts.

But the o-ring is definitely the cheapest way to go.
 
Sinistar said:
Maybe I should clarify. My wing fuel drain has outside threads. I figured I could maybe just find some plumbing-like cap (brass?) To lightly screw over it...a cap.
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Ahh. That makes more sense now.

I’ve never seen that style sump fitting.
 
Sinistar said:
Maybe I should clarify. My wing fuel drain has outside threads. I figured I could maybe just find some plumbing-like cap (brass?) To lightly screw over it...a cap.

I never intended to remove a drain (with a near full tank) to install a temporary plug and then do it again to actually fix it.

It just seems like there must be a simple 1/2" threaded cap (okay, that was a guess on the thread size) I could find to screw over it until the mechanic fixes it. No leaks until it's fixed - check! Can be removed to sump - check!
Click to expand...

Sounds odd. Best to let a mechanic gets hands on.
 
Sinistar said:
Maybe I should clarify. My wing fuel drain has outside threads. I figured I could maybe just find some plumbing-like cap (brass?) To lightly screw over it...a cap.

I never intended to remove a drain (with a near full tank) to install a temporary plug and then do it again to actually fix it.

It just seems like there must be a simple 1/2" threaded cap (okay, that was a guess on the thread size) I could find to screw over it until the mechanic fixes it. No leaks until it's fixed - check! Can be removed to sump - check!
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Gotta see pictures, I don't believe any approved wing drain has external threads.
 
I posted a pic a few a few messages back.

The drain looks like it is cinched up against the disc/bottom of the wing with a nut that is also safety wired. That nut goes far enough on the threads that there are enough threads leftover to screw on a cap or something without touching the holding nut or safety wire. Ours has more empty threads than the one in the picture.
 
weirdjim said:
Take a small fuel sample. Twist the sample nipple a few degrees. Sample again. Twist the sample nipple a few degrees. Sample again. Leak gone? You chased a microscopic dirt/sand/rust particle out of the sealing o-ring. Still there? Follow Tom's advice, run the tank dry and replace the o-ring.

Thankful to the Holy St. Potluck, our winter appears to be over. 60df and clear for the first time since November. Whuff. I've seen worse, but I've seen milder.


Jim
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I'll give this a shot tomorrow morning when I check on it. Great idea to get it seated until it can be fixed.
 
Tom-D said:
Gotta see pictures, I don't believe any approved wing drain has external threads.
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I get the impression that this style is used after bladder replacement. Not sure if it is prefered overy whatever was std in 1972. I am pretty sure it's FAA approved.
 
Sinistar said:
I posted a pic a few a few messages back.

The drain looks like it is cinched up against the disc/bottom of the wing with a nut that is also safety wired. That nut goes far enough on the threads that there are enough threads leftover to screw on a cap or something without touching the holding nut or safety wire. Ours has more empty threads than the one in the picture.
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You must have new bags, what you show is a part of the fuel bag in the wing. You don't change them you simply change the o rings.
placing a cap without sealing the threads will not work.
 
Sinistar said:
Another good idea, thanks! Ill use a blow torch, that should be quicker...kidding:)

If that doesnt work: per Tom's earlier advice, ill go fly off 37 gallons off right now at night in IMC which should only take 4 hrs and requires running a tank dry at night...and im not instrument rated.....sorry @Tom-D I couldnt resist :)
Click to expand...

There is another thread going on about running one tank dry just to help ya out . Sorry dude, I know you had enough hangar trouble and now this putting a damper to your flight regime .
 
Tom-D said:
You must have new bags, what you show is a part of the fuel bag in the wing. You don't change them you simply change the o rings.
placing a cap without sealing the threads will not work.
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Yeah, this.
 
I am wondering if the cap idea would even work, due to the limited number of threads. You’d need some type of seal (teflon tape), or an oring at the base (top) of the cap.

Let us know what you ended up doing.
 
Looks like you have the ones sold by Eagle Fuel Cells for the post AD84-10-01 fuel bladders. Most likely installed under an STC that has an ICA. Look at that if you have it. Also you can call Eagle and see what they say. Some info here.
 
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