More fuel tank leak questions

[Mark89114]

Before I start a super involved research and trouble shooting plan.....want to get everybody's opinion on these leaks.  This is right at wing root on pilots side.  There is only a tiny amount of wetness around what I assume is the main fuel pickup and the 4 rivet looking things are noticeablely wetter.  I poked my head up in the wheel well and felt around a bit and slight trace in there.  Nothing is dripping.

Should I clean them off real good and positively identify where it potentially is coming from or leave the witness stains?  

I am in the middle of redoing carpet (another thread topic and down for a registration issue) so time is not super critical.  Just want to get it done economically and timely.  My mechanic repaired one leak years ago and no issues so he has the skills sets but he likes having some ideas before tackling complex tasks.

Mark

 

[1980Mooney]

7 minutes ago, Mark89114 said:

Before I start a super involved research and trouble shooting plan.....want to get everybody's opinion on these leaks.  This is right at wing root on pilots side.  There is only a tiny amount of wetness around what I assume is the main fuel pickup and the 4 rivet looking things are noticeablely wetter.  I poked my head up in the wheel well and felt around a bit and slight trace in there.  Nothing is dripping.

Should I clean them off real good and positively identify where it potentially is coming from or leave the witness stains?  

I am in the middle of redoing carpet (another thread topic and down for a registration issue) so time is not super critical.  Just want to get it done economically and timely.  My mechanic repaired one leak years ago and no issues so he has the skills sets but he likes having some ideas before tackling complex tasks.

Mark

 

It looks like the gasket on your fuel pickup is leaking.  That may be the source of the fuel that is seeping into the wheel-well.  The pickup is at the highest point - with the interior in place it doesn't evaporate as fast and the liquid avgas will find its way down with gravity eventually into the wheel well where it evaporates leaving the dye stain.  I personally would replace the pickup gaskets, clean it up and then look for any leaks that might be from the tank. 

Your interior must reek of avgas when you open the door.  Let's see what the A&P's here say....

[EricJ]

+1 that the first thing to check is the gasket on the fuel pickup.    It even looks like it might just be the bottom screw is loose.    Be very gentle about tightening those, but it might be worth just checking to see if the screws are a little loose.   If so, just snugging a bit and then cleaning up the stains may be a good approach, and then see if the odor continues and come back later and check for more staining.   If not, good to go, if so and it looks like it's around the pickup again, a new gasket might be in order.

The inner fuel sending unit is nearby, is there any staining around it?

[Guest]

Clean the blue staining with Acetone, then observe the area to see if you can find the source.  As noted above, there are two potential sources, the fuel pick up and the inboard fuel quantity transmitter.

[Mark89114]

After a sabbatical on this project.....i got in there and cleaned with acetone.  Saw a drip come off the fuel pickup connection. Will gently tighten the screws a bit, but one of them is hidden behind the fuel pickup tube which presents some problems. Does anybody know if this gasket is readily available?

[glbtrottr]

Mooney charges an obscene amount of money for that viton gasket of 1/8” (I believe) which you can readily manufacture as an owner produced part. Love the factory but …really?


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[Guest]

From the IPC, part of item 40.  I’d drain the tank and remove the screws clean and inspect the gasket first. They’re $35.00 each

[glbtrottr]

From the IPC, part of item 40.  I’d drain the tank and remove the screws clean and inspect the gasket first. They’re $35.00 each

Perhaps I got charged California rates ? Or a premium for doing my annual elsewhere?


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[0TreeLemur]

The left pickup on our J looks just like the above photo, including the blue staining on the lower screw head.  Are these gaskets a factory part or available elsewhere?

A couple of years ago I had a leaking fuel sender gasket.  We replaced with a PMA rubber gasket first, but it wouldn't seal.   Next we replaced it with a cork gasket with applied Permatex.   That solved the problem. 

What's the deal with the viton gaskets?   Why do they loose their ability to seal?  Frustrating.

[carusoam]

Viton is supposed to last inifinitely…  (Viton rubber is carbon, fluorine, and hydrogen, creating a fluorine elastomer)

But, as far as compressible materials go… it is important to torque them all the same…

the leaks might be more of a proper install issue…

probably best to start with a new seal, and follow the install procedure best you can…

PP thoughts only, not a seal… 

Best regards,

-a-

[N201MKTurbo]

Just take it apart, clean everything real good including the gasket. Apply a thin brush coat of tank sealant to all 4 surfaces and reassemble. It will never leak again. And you can get it apart in the future if you need to.

[Fly Boomer]

On 2/4/2023 at 4:16 AM, N201MKTurbo said:

Just take it apart, clean everything real good including the gasket. Apply a thin brush coat of tank sealant to all 4 surfaces and reassemble. It will never leak again. And you can get it apart in the future if you need to.

CS-3330 sealant?

[N201MKTurbo]

3 hours ago, Fly Boomer said:

CS-3330 sealant?

Yes. but you should thin it with MEK so you can put on a thin coat.

[Mark89114]

Well I took the easy way out and just tightened screws up a bit.....that didn't work.  Will get a new gasket ordered and install per instructions