Fuel weep inside of cabin from the right wing

[larrynimmo]

when my right wing is near full of fuel, or if it gets cold outside I get a fuel odor in my cabin....while avionics crew is pulling wires I took pictures of my fuel pick-up fitting, and fuel level sender mount are both leaking.  I was wondering if the screws could be tightened...are the nuts attached to a flange on the other side...am I going to have to take the tank apart and redo epoxy from the inside of the tank to get it to stop leaking?

Picture need rotate 90picture is upside down

Edited March 8, 2019 by larrynimmo
tried to rotate

[DVA]

It’s interesting that someone decided to smear Buna-N (the red film) on the inside. That’s not a sealer (it’s put on as a top coat over the sealer) but it’s also unlikely to be part of your current problem. You could try making sure the screws are tight but I doubt it will help much, with the caution that you might make it worse. Both the sender and the pickup seem to be leaking from what I can see, right?

 

As the resting pressure of the fuel increases with fuller tanks, you get more weeping. The sealant becomes less pliable over time and temperatures affects it more, and the gaskets on both units degrade.

 

This looks like an relative easy fix if you are only leaking past the gaskets. Both units can be manipulated through just the top aft fuel panel. Here’s a pic of what the inside looks like if you e never seen it. We do fuel tank reseals regularly, I see this often.

 

 

 

DVA

 

 

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[buddy]

You should be able to just remove the screws and replace the gaskets. Give laser a call and they should have the gaskets in stock.

[Oldguy]

I had the same "fragrance" in my '84 J and tightening the screws on the fuel pickup did the trick for me, although you look like both the pickup and sender need tightening on yours. I was worried I needed to replace the gasket, and then found out it is a $60 part!

Once you get them all tightened, clean off the residue from the leaks and watch it for a few days. It should stay clean. If not, then it is time to get your local mechanic involved. Good luck!

[Igor_U]

Gaskets (for fuel sender) were cheap when I replaced them. I believe I still have a spare one and are common to Piper aircraft... I would have to look for it in my hangar and get p/n.

[Marauder]

when my right wing is near full of fuel, or if it gets cold outside I get a fuel odor in my cabin....while avionics crew is pulling wires I took pictures of my fuel pick-up fitting, and fuel level sender mount are both leaking.  I was wondering if the screws could be tightened...are the nuts attached to a flange on the other side...am I going to have to take the tank apart and redo epoxy from the inside of the tank to get it to stop leaking?

Picture need rotate 90picture is upside down

 

You have a cork gasket sitting underneath. Tightening a little may stop the leak.

 

 

Bladder system.

 

 

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[Bryan]

Those of you that have installed CiES senders, do they come with new gaskets?

ordered the senders and want to be prepared for the install to have everything needed.

[EricJ]

I had a similar issue and (carefully) tightening the screws solved the problem.   I've since installed new senders, etc., so that was the bigger cure. 

1 minute ago, Bryan said:

Those of you that have installed CiES senders, do they come with new gaskets?

ordered the senders and want to be prepared for the install to have everything needed.

I believe new gaskets are included, or at least I didn't get charged for gaskets when mine was put in. 

[Marauder]

Those of you that have installed CiES senders, do they come with new gaskets?
ordered the senders and want to be prepared for the install to have everything needed.

Yes. Old and new senders next to each other




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[Marauder]

I did install new screws and didn’t reuse the old ones.


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[Bob_Belville]

I think there's a torque spec on those perimeter screws - Clarence will be along shortly to confirm - you want to squeeze that gasket tight enough and uniformly. Cork is probably more sensitive to proper installation. There's a rubber gasket alternative that's thicker an probably more forgiving and longer lasting. @M20Doc

[Guest]

Here is your torque value.  Some Acetone on a rag will clean up the old fuel dye.

Clarence

 

[Bob_Belville]

Thanks Clarence, that's what I was remembering. Turns out that the right way to screw 5 small screws is not trivial. It reinforces the old saw about how it's the things we know that ain't so that gets us in trouble.

[EricJ]

It also says that retorquing to prevent leaking is okay.

[larrynimmo]

It’s leaking pretty good from one of the screws for the fuel pixup...looking to see if I can fix with taking out tank access covers...just one screw leaking

[Oldguy]

21 hours ago, larrynimmo said:

It’s leaking pretty good from one of the screws for the fuel pixup...looking to see if I can fix with taking out tank access covers...just one screw leaking

It's always the one under the pickup tube because it is a bear to get tightened and torqued properly.

[Guest]

On 3/9/2019 at 2:39 PM, larrynimmo said:

It’s leaking pretty good from one of the screws for the fuel pixup...looking to see if I can fix with taking out tank access covers...just one screw leaking

Remove the screw and replace it with an AN3 bolt, much easier to torque with a crows foot wrench.  Transfer the washer to the bolt.

Clarence

Edited March 10, 2019 by M20Doc

[N201MKTurbo]

I re did one of my senders three times and it still leaked, so I put a light coating of tank sealant on the sender, the airframe and both sides of the gasket. It didn't leak a single molecule of fuel after that. I had to remove it about a year later and was thinking it would be a horror story getting it apart, but it wasn't that hard and cleaning it up for a reseal was no big deal. 

I know it isn't by the book, but it works.

BTW, it wouldn't reseal because too many ham fisted mechanics were in there before I bought the plane!

[LANCECASPER]

36 minutes ago, N201MKTurbo said:

I re did one of my senders three times and it still leaked, so I put a light coating of tank sealant on the sender, the airframe and both sides of the gasket. It didn't leak a single molecule of fuel after that. I had to remove it about a year later and was thinking it would be a horror story getting it apart, but it wasn't that hard and cleaning it up for a reseal was no big deal. 

I know it isn't by the book, but it works.

BTW, it wouldn't reseal because too many ham fisted mechanics were in there before I bought the plane!

Good job! Who would have figured?  Fuel sealant actually seals fuel.

[larrynimmo]

Completion Report....

I completely removed the bottom fuel pick-up tube cleaned up the whole area with acetone and it cleaned up nicely.., installed a new $62 mooney gasket, put non hardening Permatex on the threads, and that was fixed.  As for the fuel gauge I couldn't get it to pop loose (must be glued in place) removed old screw, installed new screws with the nylon crush bushing barrels, new screws and a light coating of non hardening Permatex and torqued everything.  I only went to 15 inch pounds because it felt pretty tight at that.  I also, took the opportunity to replace the 40 year old fuel hose, and installed a new quick drain for the tank.  FYI if you order a fuel sender gasket from Mooney they are now sending a rubber one rather than the cork ones...it cost $28, but I ended up not using it.  The plastic barrel bushings only cost $.50 each.  Put 25 gallons in the tank...and no leak what-so-ever.  YEAH!

My A&P mechanic told me that you don't need sealant on the screws (even though we did it) because when you use a new gasket the crushing force of the compression is supposed to seal the screw threads so that nothing can pass through.

[carusoam]

Great detailed follow-up and pics, Larry!

Nice Fuel hose too... the old 60s original ones get really cracky... brittle.

Your old ones were probably pretty ripe... even if they looked nice from the outside...

Best regards,

-a-

[Rwsavory]

1 hour ago, larrynimmo said:

Completion Report....

I completely removed the bottom fuel pick-up tube cleaned up the whole area with acetone and it cleaned up nicely.., installed a new $62 mooney gasket, put non hardening Permatex on the threads, and that was fixed.  As for the fuel gauge I couldn't get it to pop loose (must be glued in place) removed old screw, installed new screws with the nylon crush bushing barrels, new screws and a light coating of non hardening Permatex and torqued everything.  I only went to 15 inch pounds because it felt pretty tight at that.  I also, took the opportunity to replace the 40 year old fuel hose, and installed a new quick drain for the tank.  FYI if you order a fuel sender gasket from Mooney they are now sending a rubber one rather than the cork ones...it cost $28, but I ended up not using it.  The plastic barrel bushings only cost $.50 each.  Put 25 gallons in the tank...and no leak what-so-ever.  YEAH!

My A&P mechanic told me that you don't need sealant on the screws (even though we did it) because when you use a new gasket the crushing force of the compression is supposed to seal the screw threads so that nothing can pass through.

Thanks for your report.  This will help a lot of folks in the future.

 Versachem Prime Seal Type 3 Aviation also does the trick on these leaky screws.  We replaced a sender gasket last year, and I had to use this to stop seepage. Re-torqueing alone was not sufficient.  

[larrynimmo]

On 3/8/2019 at 8:07 PM, M20Doc said:

Here is your torque value.  Some Acetone on a rag will clean up the old fuel dye.

Clarence

 

I don’t trust this instruction....first off senders only have 5 holes.  When I tightened mine, I felt very uncomfortable torquing to 15 inch pounds....and I do believe I made the right decision not to go further....The screws for this are a 6/32...look at the torching guide in the mooney service manual.  Size 6 isn’t listed, but use size 8 as a guide

[Guest]

I’ve never seen a fuel quantity transmitter held on with 6-32 screws.  They have always been 10-32 screws or bolts.  

Clarence

Edited March 25, 2019 by M20Doc

[larrynimmo]

Trust me 6/32