Weeping Drain Valves

[skippydiesel]

My Sonex wing tanks have SAF-AIR push type fuel drain valves.

They leak or rather they weep very slowly.

The whole aircraft, including valves, have only done 185 hrs in about 2 years and the valves have been leaking for most of that time.

I make a point of pulling each one down after every preflight drain – doesn’t help.

The weep is so slow that this is more of an aesthetic problem – stains on my wings, than any practical issue.

All helpful suggestions welcome😈

[rodgerc]

Tena pads or Depends if it’s only minor leakage. 

Edited 22 hours ago by rodgerc

[djpacro]

17 minutes ago, skippydiesel said:

My Sonex wing tanks have SAF-AIR push type fuel drain valves.

They leak or rather they weep very slowly.

I've had the same problem with new drain valves. Take them out and clean them - dirt or a burr is enough to open them enough to leak. Have a friend with you to stick their finger in the hole or have a plug (perhaps an old valve) ready to screw in.

[facthunter]

I usually just give them a few twists each way while holding them DOWN if they are the Item I'm thinking of. Nev

[skippydiesel]

29 minutes ago, djpacro said:

I've had the same problem with new drain valves. Take them out and clean them - dirt or a burr is enough to open them enough to leak. Have a friend with you to stick their finger in the hole or have a plug (perhaps an old valve) ready to screw in.

Or use up all the fuel - just topped up the tanks today, so will be a while before empty.

 

This should not happen though - must be a crap design if so easily defected.

 

Will try your suggestion - nothing to lose except the staines and very slightly lower fuel consumption.😈

[facthunter]

 Remove and have a Plug or cork ready and clean and Lap it, then put it back in. Do you Filter your fuel or is there any sediment showing in your drain sample.  Nev.

[Blueadventures]

Don't fly while dripping fuel leak under a plane, back fire on start up, small pool of evaporating fuel and light breeze wrong way and you have a fire possibility.  Happened at Proserpine to an RAA aircraft a few years back.  I don't like the push up steel (get rusty) ones, not uncommon to leak and need replacing.

Edited 19 hours ago by Blueadventures

[Moneybox]

You most likely have a bit of sediment in the tank. Try opening them fully a couple of times to hopefully flush it enough to seal the contact area.

[BrendAn]

I replaced my Curtis valve. Not cheap at $54 but now it's always dry under the plane. Used to be greeted by a big wet patch on the floor each weekend. Didn't like that when av gas is $2.80 p/l

[Thruster88]

I would buy a replacement, $30-50 aussie from aircraft spruce australia. Depending on which type you have the o-ring could be replaced and you will have a spare. The flush, cessna style, look like they are sealed for life.

[skippydiesel]

12 hours ago, Blueadventures said:

Don't fly while dripping fuel leak under a plane, back fire on start up, small pool of evaporating fuel and light breeze wrong way and you have a fire possibility.  Happened at Proserpine to an RAA aircraft a few years back.  I don't like the push up steel (get rusty) ones, not uncommon to leak and need replacing.

Thats an ATEC Zephyr and the initial fire is concentrated in the engine bay - not the fuel tank area.😈

[skippydiesel]

11 hours ago, Moneybox said:

You most likely have a bit of sediment in the tank. Try opening them fully a couple of times to hopefully flush it enough to seal the contact area.

Shouldn't have but wont discount completly;

• Tanks were well flushed before test flights.
• ALL fuel is passed through a Mr Funnel
• In 195 hrs, no contaminants appear in pre flight fuel drainings

I have tried a prolonged drain/flush  no improvement. 

 

Next time tanks are empty, will remove drain valves and attempt a clean - see what happens.😈

[skippydiesel]

1 hour ago, Thruster88 said:

I would buy a replacement, $30-50 aussie from aircraft spruce australia. Depending on which type you have the o-ring could be replaced and you will have a spare. The flush, cessna style, look like they are sealed for life.

These are new valves - they should not need to have the o-rings replaced but if all else fails I will certainly replace them in the hope of a fix😈

[skippydiesel]

12 hours ago, BrendAn said:

I replaced my Curtis valve. Not cheap at $54 but now it's always dry under the plane. Used to be greeted by a big wet patch on the floor each weekend. Didn't like that when av gas is $2.80 p/l

What did you replace the Curtis valves with?😈

[BrendAn]

52 minutes ago, skippydiesel said:

What did you replace the Curtis valves with?😈

Another Curtis valve. Genuine Curtis brand

[Moneybox]

1 hour ago, skippydiesel said:

These are new valves - they should not need to have the o-rings replaced but if all else fails I will certainly replace them in the hope of a fix😈

 Try to buy the ones with a male thread. Excessive weeping is usually a female trait. 

[facthunter]

Jesus Wept.  Nev

[Blueadventures]

For forum members information (excluding Skip because he is always negative and won't believe this is correct).  The leaky fuel tank drain has flames at it, burnt grass area to starboard side of front end as that's where the vapour would have been going (refer smoke plume drift).  Ignition occurred and source spread, prop wash extinguished grass fire but not the aircraft fuel areas.  Owner was seated in cockpit doing a start to provide an engine run (wing cover on and still tied down).  When fire observed he made a radio call to alert airports fire rescue, they don't monitor outside of RPT, he made further communication to ARO and operator about this.

[Moneybox]

36 minutes ago, facthunter said:

Jesus Wept.  Nev

I never read that book...

[facthunter]

The shortest sentence in the Bible. I didn't finish it either as someone  told me how it ended. Nev

[facthunter]

Getting back to the drain Valves. I don't like relying on a spring OR an "O" ring. The drain VALVE(s) should all be located in the Lowest parts of the section they drain from and would frequently be in contact with water making steel unsuitable for the seating Parts, long term. Nev