How to seal my fuel sender to avoid drips?

[neilpilot]

After buying our 65C in 2012, we had our right tank's fuel sender O/Hed, and a new gasket was used when it was installed.  Recently we discovered a slight but active drip at the sender.  We were able to tighten the screws to stop the drip, but consider this a temporary fix.  We plan to have our local A&P replace the gasket, but have a few questions.

When tightening the 6 screws, we discovered that one screw would not tighten.  I assume that the nut plate is damaged behind that one screw.  What's the recommended fix for this issue?

Also, when the gasket is replaced, should the mechanic use any Permatex or other dressing on the gasket?  Should he use some tank sealer on the screws?

[Bob_Belville]

You would not normally need or want any sealant on that gasket. Be sure to tighten the screws evenly and there a torque spec. With the tank empty and the sender off you can determine whether the nut plate is spinning which would seem to me to be unlikely. But I suppose you're not anxious to drain the tank if you can help it.

I'm headed to the airport where Lynn is installing bladder cells and CiES sender in my plane right now. My bladders would have different nuts but I'll ask him if he's ever encountered a problem.  

[N201MKTurbo]

I had one that I could not get to stop leaking. I tried 4 different gaskets, new screws and new insulators. I finally coated both sides of the gasket with cover plate sealant and put it together. It didn't leak any more. I actually had to remove it after that and it was hard but doable. You just have to pry it off like a cover plate.

[Bob_Belville]

You would not normally need or want any sealant on that gasket. Be sure to tighten the screws evenly and there a torque spec. With the tank empty and the sender off you can determine whether the nut plate is spinning which would seem to me to be unlikely. But I suppose you're not anxious to drain the tank if you can help it.
I'm headed to the airport where Lynn is installing bladder cells and CiES sender in my plane right now. My bladders would have different nuts but I'll ask him if he's ever encountered a problem.  

Lynn says the nut assembly probably has failed. You'll need to drain tank and repair. Pic is a cover plate but sender cover is similar.

Sent from my XT1254 using Tapatalk

[neilpilot]

1 minute ago, Bob_Belville said:

Lynn says the nut assembly probably has failed. You'll need to drain tank and repair. Pic is a cover plate but sender cover is similar.

Sent from my XT1254 using Tapatalk
 

Bob - please tell Lynn I appreciate his advice.  I already planned on draining the tank before removing the sender.  Can this nut assembly be replaced by reaching in from the sender's hole, or does the tank need to be opened in another area (I hope not)?

[Bob_Belville]

57 minutes ago, neilpilot said:

Bob - please tell Lynn I appreciate his advice.  I already planned on draining the tank before removing the sender.  Can this nut assembly be replaced by reaching in from the sender's hole, or does the tank need to be opened in another area (I hope not)?

It is an easy repair once the tank is drained and the level sensor is removed.

[Guest]

Depending on your skills and the tools available, a damaged nut plate can be changed thru the transmitter hole.

Clarence

[neilpilot]

1 hour ago, M20Doc said:

Depending on your skills and the tools available, a damaged nut plate can be changed thru the transmitter hole.

Clarence

Is the replacement nut plate a standard part or Mooney specific?  I'm not familiar with how they are changed, but it almost looks like the mounting tabs are carefully bent outward to allow the plates to be swapped, and then bent back in to secure the new plate.

[Bob_Belville]

23 minutes ago, neilpilot said:

Is the replacement nut plate a standard part or Mooney specific?  I'm not familiar with how they are changed, but it almost looks like the mounting tabs are carefully bent outward to allow the plates to be swapped, and then bent back in to secure the new plate.

I think your A&P will drill out the 2 rivets and replace the nut ass'y. (But... I am not an A&P.)

http://www.aircraftfast.com/floating_nut_plates.htm

 

[Guest]

6 hours ago, neilpilot said:

Is the replacement nut plate a standard part or Mooney specific?  I'm not familiar with how they are changed, but it almost looks like the mounting tabs are carefully bent outward to allow the plates to be swapped, and then bent back in to secure the new plate.

The part will most likely be a standard MS part number, either sealed or open style. With a screw removed, poke a length of safety wire into the screw hole to see if it’s open or sealed.

Clarence

[RLCarter]

On mine there is a doubler inside the tank, sealed nut plates are riveted to the doubler and the doubler is riveted to the rib, there is an inspection plate under the wing that allows access from the bottom

[bradp]

Can you really get a rivet hand squeeze yoke through the sender cutout Clarence?  

Can you do the same trick Don Maxwell recommends for cracked nut plates - a dab of aviation gasket maker on the screw head?  I tried this method for a inspection plate and did not have good success.  The cure was to do it the "right" way.  

I guess the backup plan involve a good pair of mechanics fingers and a magnetic pickup telescoping wand :-)

 

[Guest]

5 hours ago, bradp said:

Can you really get a rivet hand squeeze yoke through the sender cutout Clarence?  

Can you do the same trick Don Maxwell recommends for cracked nut plates - a dab of aviation gasket maker on the screw head?  I tried this method for a inspection plate and did not have good success.  The cure was to do it the "right" way.  

I guess the backup plan involve a good pair of mechanics fingers and a magnetic pickup telescoping wand :-)

 

You don’t have to use solid squeeze rivets to install the nut plate.  Cherry makes a 3/32” pull rivet meant to hold nutplates on.

http://www.aircraftspruce.ca/catalog/hapages/CCC32cherryRivets.php?clickkey=5167

Clarence

[Gary0747]

Seepage around fuel senders seems to be a continuing problem   Perhaps irregularities or distortion in the wing spar are part of the problem.  Has anybody had good results using a thicker gasket or a rubber gasket? 

[jetdriven]

We use the cork gaskets.  After several rounds of the new neoprene rubber gaskets leaking, the old style is better.  

[Gary0747]

1 hour ago, jetdriven said:

We use the cork gaskets.  After several rounds of the new neoprene rubber gaskets leaking, the old style is better.  

What thickness and do you coat them with permatex #2or #3?