Fuel leak under wing but I have bladders.

[rbridges]

I did a little more inspecting today.  I've flown once and done steep turns, and I've left the tanks full (1/4" from top) for a week.  I can't reproduce any leaks or smells.  Anyway, I removed a top inspection plate and saw this staining.  To me, it looks like it may have leaked from the edge of the plate.  At least the leak is up pretty high in the bladder.  The only other think I could think would be the filler neck leaking on the far side near the vent.  BTW, is the white powdery reside below it from dried 100LL or is it dried adhesive from the duct tape.

 

Edited March 22, 2020 by rbridges

[carusoam]

RB,

Did you post the video in YouTube?

Then copy the link here?

I am only seeing a do not enter sign... on my iPad.

100LL... light blue, dark blue, brown, tar....   opposite of white powder... 

Best regards,

-a-

[rbridges]

38 minutes ago, carusoam said:

RB,

Did you post the video in YouTube?

Then copy the link here?

I am only seeing a do not enter sign... on my iPad.

100LL... light blue, dark blue, brown, tar....   opposite of white powder... 

Best regards,

-a-

No, just copy and paste an image. I'll try uploading to MS. 

Edited March 22, 2020 by rbridges

[ArtVandelay]

No, just copy and paste an image. I'll try uploading to MS. 

What’s the duct tape doing there? I thought it was a frowned upon because it can absorb moisture?

[rbridges]

6 minutes ago, ArtVandelay said:

What’s the duct tape doing there? I thought it was a frowned upon because it can absorb moisture?

It's actually in the bladder install manual IIRC. I think it prevents damage to bladders from sharp edges. 

The image shows tape on side walls.   So.e kind of styrofoam is present on bottom. 

[carusoam]

Duct tape was used by Mooney to seal the cabin near the wings... it didn’t last very long in 1960s materials...

PVC makes a nice, soft, slippery, surface... if that keeps bladders from hanging up...

Duct tape uses a thread mesh for tensile strength... looks like old adhesive and a mesh pattern may have been left behind...

PP thoughts only, not a mechanic...

best regards,

-a-

[DXB]

@rbridges @MoonFlyer68 Would you mind posting what the solution to your issue was?   It just started for me, on both sides  simultaneously. The plane sat with tanks about half full for a week.  Both developed modest amounts of thick blue goo around the identical hole under the wing pictured by @rbridges. The left side also had a little blue goo on the floor.   I'm really hoping it's an interconnect tube clamp and not the bladder itself.  I'm wondering exactly where to look first.    

[rbridges]

5 minutes ago, DXB said:

@rbridges @MoonFlyer68 Would you mind posting what the solution to your issue was?   It just started for me, on both sides  simultaneously. The plane sat with tanks about half full for a week.  Both developed modest amounts of thick blue goo around the identical hole under the wing pictured by @rbridges. The left side also had a little blue goo on the floor.   I'm really hoping it's an interconnect tube clamp and not the bladder itself.  I'm wondering exactly where to look first.    

 

At my annual with Cole aviation, he said he tightened a clamp, and it seemed to take care of it. Just looking at the bladders, I’d be surprised if they sprung a leak, they’re pretty thick. 

[MoonFlyer68]

On 6/28/2025 at 5:50 PM, DXB said:

@rbridges @MoonFlyer68 Would you mind posting what the solution to your issue was?   It just started for me, on both sides  simultaneously. The plane sat with tanks about half full for a week.  Both developed modest amounts of thick blue goo around the identical hole under the wing pictured by @rbridges. The left side also had a little blue goo on the floor.   I'm really hoping it's an interconnect tube clamp and not the bladder itself.  I'm wondering exactly where to look first.    

 

When I had mine fixed, we made a family vacation trip up to Pennsylvania and had Griggs check all the fittings.  Not a single drop since then.  As a bonus, they gave me a nice metal fuel stick with my tail number on it.  Very nice people.