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Theo
04-11-2013, 05:43 PM
My left wing tank has a leaky fuel drain valve. It is a drip once every 5 to 10 seconds. Is this a difficult fix?
I suppose draining the tank is part of the fix and then does the valve just screw out?

andya
04-11-2013, 07:47 PM
afterdraining tank,valve removes, if a curtis type, need to buy replacement, not sure on other brands

Theo
04-11-2013, 08:09 PM
So it just screws out?
I found this slide show on line so it looks pretty simple. Mine is the second style that has the bar across it.
http://www.slideshare.net/jonespub/how-to-change-piper-leaking-fuel-drain

Thank you.

Bruce
04-11-2013, 09:07 PM
There are replacement parts available for Curtis drains.

rwdurham
04-11-2013, 10:46 PM
Hard landings Theo? :) Seriously, I've never replaced a fuel drain in a Tri-Pacer but I have in other Pipers, aka, Cherokee's. Not sure if it applies here, but use caution in over tightening. If you crack the boss (I think that's what it's called) it gets a little pricey. Somebody else can probably clear that up for you.

gliderman
04-11-2013, 11:07 PM
Theo
I replaced mine recently. I grabbed a buddy and we changed them without draining the fuel. we had new ones all set up to be installed c/w fuel lube on the threads of the new ones. one of us handled the wrench while the other was ready with his thumb. as the old one came out we quickly plugged the hole with a thumb. grabbed the new one and very quickly moved the thumb while the other one guy screwed in the new one- lost less than a 1/2 pint out of each wing.
if I was to do it again I would use a rubber glove and a rag wrapped around the wrist. I love the smell of avgas but I didn't get to a shower for a while and I stunk
hope this helps but if you would rather drain the tanks and don't forget to wipe down the jerry cans with a damp rag- static electricity is not our friend

hope this helps
shane-o
Shane

59pacer
04-12-2013, 01:44 AM
As I recall, Curtis no longer sell spare replacement seals, though you might find some, somewhere. Saf-air use a small O-ring seal which can be replaced. I got rid of the Curtis type and went to the Saf-air CAV-110.
Again, have it ready, complete with fuel lube, and be quick. A helper with a thumb is enough, besides, the fuel will run down his arm! You'll lose a pint at most, but I wouldn't do the job in the hangar.

MN_flyer1
04-12-2013, 07:28 AM
If it is the right tank you can fly it to empty. Then there is no dripping. The left tank takes a little more coordination to get empty.

Tim

sdemeyer
04-12-2013, 09:35 AM
+1 on the safe-air drains. They use a common ms oring, easily replaceable. If you drain the tanks, you will have a good opportunity to clean and lube and inspect the fuel selector valve, if your still using the original piper selector. Takes care of the valve AD. I used safe-air cav-160 on my pacer. These are the flush ones that push up to drain.

smcnutt
04-12-2013, 09:40 AM
We've replaced the o-rings and ended up having it leak again. Since we could buy a new valve for so little we simply replaced it after that. When we just did the o-ring we drained the tank but when we replaced the whole valve we didn't bother. As others said, didn't loose much fuel in the process.

Dwain
04-12-2013, 11:07 AM
After sumping the tanks, my right valve started leaking several drips a minute. Apparently, there was some trash in the seat, I messed with it for a few minutes and it quit and has not done it again. I have also heard of people blowing a little bit of air through them, but it seems like a bad idea to blow the trash back into the tank. - Dwain

61Chuck
04-12-2013, 11:45 AM
Hard landings Theo? :) Seriously, I've never replaced a fuel drain in a Tri-Pacer but I have in other Pipers, aka, Cherokee's. Not sure if it applies here, but use caution in over tightening. If you crack the boss (I think that's what it's called) it gets a little pricey. Somebody else can probably clear that up for you.

From the Curtis wall chart pipe thread torque specifications.

1/8-27 N.P.T. 40-45 in. lbs
1/4-18 N.P.T. 80-85 in. lbs
3/8-18 N.P.T. 105-115 in. lbs
1/2-14 N.P.T. 155-165 in. lbs

Curtis valves do not use o-rings they have a special flat molded seal. Using compressed air to dislodge junk around the seal may cause the seal to move and loose its bond. We had a special sump tool in the shop that everyone called the "cowbell". It had a bucket with a holding device in the center. The holding part allowed you to remove and start a new valve while the bucket captured the fuel and prevented it from getting all over you.


Todd

Glen Geller
04-13-2013, 01:36 AM
Oh, now we need a picture of the cowbell please!

walt.buskey
04-13-2013, 07:06 AM
Hey, this might be a dumb question, but....

I understand that prudence dictate we ground our AC before fueling and do whatever we can to eliminate static charges, but... what's the difference when fueling automobiles? Why is it that the ability to ground a car is not there when fueling up? Is it the pump? The fuel? The vehicle? Just curious as to why we take such care with AC but simply pump gas into our cars.

I know, simple question, but it's been bugging me for a while. Walt

gliderman
04-13-2013, 02:42 PM
Hey, this might be a dumb question, but....

I understand that prudence dictate we ground our AC before fueling and do whatever we can to eliminate static charges, but... what's the difference when fueling automobiles? Why is it that the ability to ground a car is not there when fueling up? Is it the pump? The fuel? The vehicle? Just curious as to why we take such care with AC but simply pump gas into our cars.

I know, simple question, but it's been bugging me for a while. Walt

Walt
this is somewhat long winded but......

you are fighting a hundred years of traditon when you are refueling your automobile. they should be grounded also and I believe to combat this problem the gas station hoses have a metal mesh inside the hose connected to the nozzle.

got this from the net....

Electrostatics is a problem requiring consideration in refueling because of something called triboelectric effect. It's a form of contact electrification. Any time a material comes in contact with another material - let alone moves across it like a person walking across a rug - charges can move. When two materials rub across each other (like fuel passing through a hose), charges can move resulting in a charge buildup. If the materials involved in this process are not good conductors, the charge cannot bleed off, and it will build up where ever the charges can collect. Metal fittings are a good place for that to happen.
In aircraft refueling, the first operation is the connection of a ground wire between the aircraft and the refueling vehicle. And the last thing on the checklist is to disconnect that ground wire. The problem is the same "static electricity" we encounter when we pull plastic wrap off a role. The underlying physics is the same - move something across something else, electric charges can move and an electrostatic difference of potential can build up in a nonconductive environment. Even to the point of an electric arc - which can be a disaster in refueling operations

hope this helps

shane-o

61Chuck
04-13-2013, 04:23 PM
We had a dedicated 50 gallon drum with wobble pump and grounding strap for defueling. Sucked the fuel out, never drained tank through sump took to long. Used the cow bell with a rubber hose attached to drain into the drum the residual fuel or for a quick change of the sump. As you can see from my drawing it has been a few years since I worked in GA. Had to do the drawing from memory.

Worked on KC-135A models in the Airforce, can you imagine the static energy that built up on an airframe as big as a 707 in flight? Just imagine the spark when you hooked up the fueling nozzle to the airframe! Never wanted to find out always grounded first.

walt.buskey
04-13-2013, 05:44 PM
Thanks, gliderman. I knew that the possibility of static buildup was there (always is, as per "triboelectric effect"), I was just curious as to why a separate grounding cable is not SOP with cars. Sounds like you've answered my question. WBB