Fuel weep inside of cabin from the right wing

[larrynimmo]

Trust me 6/32

At least for 24-1189...

[Ragsf15e]

On 3/10/2019 at 7:12 PM, 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!

You guys that have done this, I have a couple questions because I’m just starting to get a very faint fuel smell in the cockpit, or maybe it’s just that “old airplane” smell.  No stained carpet yet.

1.  To get to the senders and pickup, do I just remove the interior side carpets and the insulation and then they’re right there like the pictures at the beginning of this thread?

2.  If I need to replace the gaskets on the senders or pickup, can I remove them with only access from the cockpit or do we have to go in through the tank access as well?

3.  I see the senders have a newer rubber gasket.  Does the pickup have something similar?

 I hope it’s nothing, but it’s getting close to annual time and I want to put eyes on it.  Thanks!

 

[Skates97]

31 minutes ago, Ragsf15e said:

You guys that have done this, I have a couple questions because I’m just starting to get a very faint fuel smell in the cockpit, or maybe it’s just that “old airplane” smell.  No stained carpet yet.

1.  To get to the senders and pickup, do I just remove the interior side carpets and the insulation and then they’re right there like the pictures at the beginning of this thread? - Yes, easy to get to.

2.  If I need to replace the gaskets on the senders or pickup, can I remove them with only access from the cockpit or do we have to go in through the tank access as well? - It can all be done from inside the cockpit. You don't have to have the tank empty, just below the level of the sender and pickup. I don't know the level exactly, I used a battery powered pump to pump as much fuel out as I could into 5 gallon buckets when I replaced my senders. There was still a little fuel in the bottom of the tanks.

3.  I see the senders have a newer rubber gasket.  Does the pickup have something similar? - No idea.

 I hope it’s nothing, but it’s getting close to annual time and I want to put eyes on it.  Thanks!

 

 

[Ragsf15e]

1 hour ago, Skates97 said:

 

Awesome, thanks skates!  
just to clarify, is there a gasket on the pickup at all?  Or maybe you didn’t mess with that?

Edited October 13, 2021 by Ragsf15e

[Skates97]

45 minutes ago, Ragsf15e said:

Awesome, thanks skates!  
just to clarify, is there a gasket on the pickup at all?  Or maybe you didn’t mess with that?

I don't know, @M20Doc I'm sure knows. I was just swapping out the old senders with CiES senders so didn't touch the pickups.

[DonMuncy]

Easy to change the gasket. Watch out for the washers, screws etc. If not done properly, the fuel level indication will be screwed up.

[DonMuncy]

Naturally, only do it when the fuel level is below the sending unit hole. Someone else will have to tell you how many gallons that is.

[Guest]

1 hour ago, Ragsf15e said:

Awesome, thanks skates!  
just to clarify, is there a gasket on the pickup at all?  Or maybe you didn’t mess with that?

No gasket on the fuel pick up is shown, PRC and rivets.  A gasket on the transmitters though.

[Mooney-Shiner]

 

5 hours ago, Ragsf15e said:

You guys that have done this, I have a couple questions because I’m just starting to get a very faint fuel smell in the cockpit, or maybe it’s just that “old airplane” smell.  No stained carpet yet.

1.  To get to the senders and pickup, do I just remove the interior side carpets and the insulation and then they’re right there like the pictures at the beginning of this thread?

2.  If I need to replace the gaskets on the senders or pickup, can I remove them with only access from the cockpit or do we have to go in through the tank access as well?

3.  I see the senders have a newer rubber gasket.  Does the pickup have something similar?

 I hope it’s nothing, but it’s getting close to annual time and I want to put eyes on it.  Thanks!

 

Don't forget to get 2535 bushings from Lasar, you will need them for the senders' install.

[MooneyPilot145]

I noticed the fuel pickup tube on my 77' M20J is leaking into the cabin. The other photos on this thread show a Phillip's screw heads holding it on, but mine appears to be riveted to the tank. Would I have to drill them out and put a gasket between, or is it treated as a tank reseal around that area from the inside? 

Is there a retrofit kit to convert it to screws?

I've also attached a pic from the good side for reference.

 

[carusoam]

Fasteners probably aren’t your problem there MP145…

The seal between the surfaces uses a sealant…

Proper sealing of the fasteners is important as well…

Can you tell where the leak is coming from?

Is it one rivet or a sealant failure of the whole pickup…?

Pics from the other side may give a hint of how bad the sealant is behaving….

 

Any history of having the tank resealed?

A log book check may be in order…

Worst case is probably drilling out the four rivets… cleaning off the old sealant… and be done in a day…

a really bad case… the tank has ancient sealant in it, and it is breaking down…

See if you can get a pic from inside the tank…

The easy part… clean it up, see where it is leaking…  

Then decide on the proper fix…

PP thoughts only, not a mechanic…

Best regards,

-a-

[Mooney-Shiner]

8 hours ago, MooneyPilot145 said:

I noticed the fuel pickup tube on my 77' M20J is leaking into the cabin. The other photos on this thread show a Phillip's screw heads holding it on, but mine appears to be riveted to the tank. Would I have to drill them out and put a gasket between, or is it treated as a tank reseal around that area from the inside? 

Is there a retrofit kit to convert it to screws?

I've also attached a pic from the good side for reference.

 

I would check to make that it is a pick up that is leaking. If it is, then it is unlikely that the rivets themselves are leaking. On the inside of the tank the riveted area is covered with Pro-Seal sealant. It is likely that that sealant had failed. I would open the inboard tank access, apply the soapy solution and pull the vacuum through the vent while observing the possible bubbles though the plexy window.  

[Fly Boomer]

1 hour ago, ukrsindicat@yahoo.com said:

open the inboard tank access, apply the soapy solution and pull the vacuum through the vent while observing the possible bubbles though the plexy window. 

This sounds like a well-used technique.  Can you elaborate, or point me to a more in-depth description?  Thanks.

[Ragsf15e]

11 hours ago, MooneyPilot145 said:

I noticed the fuel pickup tube on my 77' M20J is leaking into the cabin. The other photos on this thread show a Phillip's screw heads holding it on, but mine appears to be riveted to the tank. Would I have to drill them out and put a gasket between, or is it treated as a tank reseal around that area from the inside? 

Is there a retrofit kit to convert it to screws?

I've also attached a pic from the good side for reference.

 

Rookie opinion… there’s no blue streak down from the gasket/rivets.  Are you sure it isn’t leaking along that lower edge?  Edit- oh that’s the good side with no blue streaks… what’s the blue smoodge at the bottom?

Second rookie question for the crowd… is there two entry points into the cabin from the fuel tank on each side?  One for the intake and one for the fuel level sensor?  I imagine one near the front of the front seats and one near the back of the front seats?

[PT20J]

11 hours ago, MooneyPilot145 said:

I noticed the fuel pickup tube on my 77' M20J is leaking into the cabin. The other photos on this thread show a Phillip's screw heads holding it on, but mine appears to be riveted to the tank. Would I have to drill them out and put a gasket between, or is it treated as a tank reseal around that area from the inside? 

Is there a retrofit kit to convert it to screws?

I've also attached a pic from the good side for reference.

 

According to the IPC, it seems Mooney changed to screws and a gasket beginning with serial number 24-0554.

[Mooney-Shiner]

2 hours ago, Fly Boomer said:

This sounds like a well-used technique.  Can you elaborate, or point me to a more in-depth description?  Thanks.

Yes, sure.  From Maxwell source:

1. The first rule to remember in chasing a fuel leak is: The source of the leak is never where the leak appears on the out side of the tank.

2. Remove the fuel from the tank. 

3. Turn the fuel selector off.

4. Remove the top fuel tank access panels on the wing that has the leak. The panels are removed by first removing the screws. 

5. Once the screws are removed, we use masking tape to tape around the access panel and the middle of the panel for protection of the paint. The panel is sealed with a sealant. Do not beat on the panels. An elephant could stand on the panel and it would not come loose.

6. Next, we use a thin putty knife, that has been sharpened on one side, to slide in between the seam of the access panel and the wing. Using a nonmetallic hammer, gently work the putty knife between the skin and panel. It may take several times around the panel with the blade and hammer, each round a little deeper under the skin, until the panel releases. 

7. Once the panels are removed we place mirrors in the bottom of the tank so that we will be able to see the upper seams of the tank. Do not cover the stringers in the bottom of the tank. Many leaks are in this area.

8. Next we apply liquid hand soap, thicker the better, to all the seams in the tank. 

9. We now cover all the removed access holes in the wing with Plexiglas. Fig. 3. The Plexiglas covers the entire hole including screw holes. The Plexiglas is held in place by masking or duct tape around the out side border forming a seal. The Plexiglas can be cut from an old windshield or purchased at most hardware stores. New glass is preferred as you will be looking thru the glass to find our leak source. 

10. Next we take a standard shop vacuum cleaner. We attach the hose from the vacuum cleaner to the vent on the fuel tank. And no, this will not collapse your tank. 

11. Turn on the vacuum and, using a flashlight, look thru the Plexiglas panel and look for bubbles in the soap. The mirrors should be positioned so that you can see the entire interior of the tank.

12. Bubbles indicate the source of the leak as air is drawn into the tank thru the leak. 

13. Once the leak, or leaks, are found, Fig .5, the area will need to be thoroughly rinsed with water, dried, cleaned and repairs made using procedures in the Mooney Service Manual..

14. Two types of sealant are recommended in the manual. PRC and Flame Master brands. We use Flame Master CS3204B-2 for repairs in the tank and topped with CS-3600 for a protective coating and CS3330B-2 for access panel sealant. Fig 6. We use sealants in Semkits that contain both sealant & activators. They are mixed together in a small caulking tube. Once mixed together, we transfer the sealant to a cup and apply with small acid brushes. The sealant will apply easily if thinned with a small amount of MEK. 

15. Replace the access panels using CS3330B-2. I recommend at least 48 hours before fuel is added to allow for proper curing of the sealant. Temperature is key to a successful repair. Avoid cold weather & high humidity if possible. 

Most leaks are easily found and repaired using this method. I share this procedure with you so that you and your mechanic can locate and repair your Mooney’s fuel leak. We welcome you to visit our service center at any time.

 

I would also add that for the horizontal surface leaks, I would use Class A compound (3204) as the Class B is too think to spread out and fill all the cavities. http://flamemaster.com/cs-3204-class-a-b-c

Can't find my old thread, here is what this diagnostic look like. I used my GoPro inserted into the wing to show the leaks. 

 

 

Feel free to ask any questions. 

@carusoam Quite honestly, by now I think we should build some sort of the primer for Tank Patching because it is such a common issue with the Mooney. 

From what I gather, the reason why Mooney suck/blow so much is because of original assembly method of the integral wing tanks. Unlike other aircraft, Mooney first assembled the tanks, then applied the sealant (other aircraft applied the sealant as they assembled the tanks). So anytime you flex the wings beyond some level (hard landing, etc), this creates a break in the sealing layer.  

 

 

Edited April 25, 2022 by ukrsindicat@yahoo.com
adding info

[PT20J]

9 minutes ago, Ragsf15e said:

Second rookie question for the crowd… is there two entry points into the cabin from the fuel tank on each side?  One for the intake and one for the fuel level sensor?  I imagine one near the front of the front seats and one near the back of the front seats?

The fuel pickup is in the lower aft part of the tank. Inside, it is down below the floor just ahead of the spar. The fuel sender penetration is just above it.

Skip

 

[Mooney-Shiner]

10 minutes ago, Ragsf15e said:

Second rookie question for the crowd… is there two entry points into the cabin from the fuel tank on each side?  One for the intake and one for the fuel level sensor?  I imagine one near the front of the front seats and one near the back of the front seats?

Yes, there are two point at each wing root. The pick up is all the way aft and bottom. Move the seat forward, remove the trim and push the wall carpet to the front

[Ragsf15e]

46 minutes ago, PT20J said:

The fuel pickup is in the lower aft part of the tank. Inside, it is down below the floor just ahead of the spar. The fuel sender penetration is just above it.

Skip

 

Ahh, got it.  One above the floor, one below.  Thanks!

[Fly Boomer]

@ukrsindicat@yahoo.com that was excellent.  Pictures are good.  Video is better.  I'll store your explanation for future reference.  Thank You!