FUEL VALVE & STRAINER ASSY - GASKET P/N CONFUSION

[DCarlton]

My fuel valve assy has been leaking for a while now; not major; about two drops per minute.  The C, D, E, F Parts Manual suggests the valve is a HE-769.  However, LASAR offers more than one seal kit for the vintage (pre J) Mooney's.  A couple of kits for the H&E 769 Selector / Gascolator, and one for the Dukes 3331 which also covers models up to J.  They also have just a gasket for the bowl, P/N 940057-001 also good for models up to J.  

Is the HE-769 seal kit most likely the correct part based on the parts manual?  I'd like to order parts before I take it to the shop again and go back into repair mode.  Appreciate your time.  

Side note; I couldn't find any seal replacement procedures in the repair manual; no torque values, etc.  Just a sketchy paragraph.  

[hammdo]

This may help on the torque info:

https://mooney.com/wp-content/uploads/2020/12/SBM20-200.pdf

pics of disassemble valve: 

 

-Don

[DCarlton]

1 hour ago, hammdo said:

This may help on the torque info:

https://mooney.com/wp-content/uploads/2020/12/SBM20-200.pdf

pics of disassemble valve: 

 

-Don

I'm really curious which type I have now.  

[DCarlton]

Found the source of my AVGAS drip.  It wasn't leaking from the bowl / gasket.  It was leaking from the nut that has to be removed every time you drop the bowl and check the screen.  I'm guessing those are aluminum fittings.  

Can someone with experience please suggest a relative torque for that nut?  Snug enough that it won't leak but still endure being removed every annual.  1/4 turn after snug contact?  

Side note (1). I'm liking the idea of having someone remove that T and install a Curtis valve more and more.  

Side note (2). Looks like I have an HE Valve / Gascolator although you can't read the P/N.  Must be a 769.  

[EricJ]

That's a common leak point.  Mine leaked from there after maintenance at a reputable shop, so I just snugged it.  And just snug, those nuts will crack if tightened too much.   It really doesn't take much to seat them properly.

Also, the bolt holding the bottom cover on the screen should be safety-wired.

[DCarlton]

1 hour ago, EricJ said:

That's a common leak point.  Mine leaked from there after maintenance at a reputable shop, so I just snugged it.  And just snug, those nuts will crack if tightened too much.   It really doesn't take much to seat them properly.

Also, the bolt holding the bottom cover on the screen should be safety-wired.

What should it be safety wired to?  I don’t see any holes in the casting. Around the T fitting?  Thanks ! 

[EricJ]

18 minutes ago, DCarlton said:

What should it be safety wired to?  I don’t see any holes in the casting. Around the T fitting?  Thanks ! 

Yes, typically just looped around the fitting.

[ArrowBerry]

I recently bought the HE fuel selector rebuild kit from Lasar. I sent Dan a couple pictures and he figured that was the right one. This is what ours looks like, and the old sticker was barely readable but HE could sorta be made out from what's left of it. Ours has been seeping undetected for a little while, the blue dye makes it look quite messy around the connections. We discovered the leak, however, by a small amount of fuel collecting inside the cockpit around the selector valve handle itself. 

I can't tell you if it's the correct one yet because we haven't installed it yet, but this is what is looks like and what Lasar recommended! 

Edited February 28, 2024 by ArrowBerry

[Shadrach]

On 2/25/2024 at 6:24 PM, DCarlton said:

Found the source of my AVGAS drip.  It wasn't leaking from the bowl / gasket.  It was leaking from the nut that has to be removed every time you drop the bowl and check the screen.  I'm guessing those are aluminum fittings.  

Can someone with experience please suggest a relative torque for that nut?  Snug enough that it won't leak but still endure being removed every annual.  1/4 turn after snug contact?  

Side note (1). I'm liking the idea of having someone remove that T and install a Curtis valve more and more.  

Side note (2). Looks like I have an HE Valve / Gascolator although you can't read the P/N.  Must be a 769.  

That does not look like the correct washer for the gascollator bowl, or perhaps the rubber has worn off causing misalignment.

[Shadrach]

It should have a stat-o-seal washer.

Does it look like the image below?

part number is 600-0101-10 $2.42ea

[Skates97]

When I talked to LASAR years ago they said the only difference in the two kits was the drawing that went with them, the seals that come in them are the same. If you look at the part numbers of the two seals that come in each kit they are the same. 

1) 600-0101-10
1) 940057-001

The torque is very specific, I wouldn't want to chance it that "just snug" isn't going to be too much and snap the bolt. There is also a tendency to snug it "just a little more" if there is a slow drip. It should be 15-20 inch-lbs. It is a very light torque.

[Shadrach]

15 minutes ago, Skates97 said:

When I talked to LASAR years ago they said the only difference in the two kits was the drawing that went with them, the seals that come in them are the same. If you look at the part numbers of the two seals that come in each kit they are the same. 

1) 600-0101-10
1) 940057-001

The torque is very specific, I wouldn't want to chance it that "just snug" isn't going to be too much and snap the bolt. There is also a tendency to snug it "just a little more" if there is a slow drip. It should be 15-20 inch-lbs. It is a very light torque.

It would take a serious ham fist to break the bolt and likely >20x the spec torque value. 15-20 inch pounds is just a few steps beyond hand tight. 

[N201MKTurbo]

I have worked on two Mooneys that had stripped out fuel sump bolts that were helicoiled. It was t me…

I just snug it up, turn on the fuel and see if it leaks. If it does I give it another 1/4 turn or so till it doesn’t leak. Then lock it down.

[DCarlton]

On 2/29/2024 at 3:11 PM, Shadrach said:

It would take a serious ham fist to break the bolt and likely >20x the spec torque value. 15-20 inch pounds is just a few steps beyond hand tight. 

"Just snug" was in reference to the fuel line fitting above the T that I was pointing to in my photo.  I torqued the bolt holding the bowl to 20 in lbs. You may be right about the washer.  I ordered a rebuild kit and a couple of spare gaskets from Lasar.  When received I'll make sure that part is in there.  Appreciate the sealing washer P/N.  

[DCarlton]

On 2/29/2024 at 2:45 PM, Skates97 said:

When I talked to LASAR years ago they said the only difference in the two kits was the drawing that went with them, the seals that come in them are the same. If you look at the part numbers of the two seals that come in each kit they are the same. 

1) 600-0101-10
1) 940057-001

The torque is very specific, I wouldn't want to chance it that "just snug" isn't going to be too much and snap the bolt. There is also a tendency to snug it "just a little more" if there is a slow drip. It should be 15-20 inch-lbs. It is a very light torque.

See attached for the drawing with P/Ns.  

Fuel Selector Service Kit.pdf