Leaking drain valve, or not?

[Pacer42Z]

I noticed what I thought my drain valve on the right main tank was leaking. So I flew the tank dry and changed the valve. Sure enough, I thought I had a bad brand new drain valve, because it leaked again. Flew the tank dry and put another new valve in. Wasn't leaking anymore I thought. However, I just didn't fill up the tank after I was flying. The first time I filled the tank before putting the Pacer back in the Hangar I came back and the drain valve was wet again.
However, I just went flying and didn't top off the tank after I was done. Sure enough, no leak. I pulled the tank cover and found the screws on the fuel sender (especially the top two) very loose. There were also fuel stains (pictures attached). I tightened the screws and filled up the tank. No more leak. Next time you can't get that fuel drain to stop leaking, check further up. When you look at the fuel stains on the tank, it shows how far the fuel can travel.

Juergen
Pacer N3342Z

[Stephen]

Nice work.

I have changed a number of valves with full tanks. I tapered a dowl to fit and slightly thread into the tank hole. Then, I losen the valve. With one hand I finish unscrewing the valve and quickly stick the wooden dowl in the hole and twist it a couple of times to hold. Then I repeat the process with a new valve. Wear rubber gloves although, I usually don't bother myself. It works. Anyone got a better idea?

[Gilbert Pierce]

I had the same problem. Thought it was drain valve and it to be the fuel sender gasket.

[Pacer42Z]

Nice work.

I have changed a number of valves with full tanks. I tapered a dowl to fit and slightly thread into the tank hole. Then, I losen the valve. With one hand I finish unscrewing the valve and quickly stick the wooden dowl in the hole and twist it a couple of times to hold. Then I repeat the process with a new valve. Wear rubber gloves although, I usually don't bother myself. It works. Anyone got a better idea?

I used to do it with fuel in the tank by wrapping rags around by wrists so the fuel wouldn't run down my elbows. Now I enjoy flying the Pacer until the engine quits on the tank that need a new valve. Then I drain the unusable fuel (about 1/4 of a gallon) and take the time to examine the threads and take the time to install the new valve.

Juergen
Pacer N3342Z

[Pacer42Z]

One of my outboard tanks has a leaking fuel drain. After taking it out I noticed a lot of dirt/"crusty stuff" at the top of the threads of the fitting in the tank. I would like to clean that out by using a tap-drill. I looked at the Piper drawing, but they don't specify the Tap size. Is it a 1/2" NPT? Also, isn't the hole in the fitting tapered as well? What is the correct specification of the tap-drill I need to buy?

Juergen
Pacer N3342Z

[MrBill]

1/4" pipe thread.quarterpipe.JPG

[MrBill]

Scratch that.
I just remembered that I may have re-tapped something after I did my tanks. I thought I could give a quick answer on that by checking whats loaded in my driver. I doubt that 1/4 is large enough.

[Jeff J]

If you know which drain valve you have you can look it up on the internet and get the thread size.

[MrBill]

It is common pipe thread so if you have the valve out just run down to your hardware store and see which fitting you can thread it into! Probably pick up the tap at the same time.

[MrBill]

Oh. do not re-drill it in fact it would be best if you just used a common plumbers wire brush on it. The kind you use to shine up the inside of a copper fitting before soldering. That is as far as I would go personally unless someone has crossed threaded it.