M20C Cabin Water Leak

[BrettKS]

I am a new M20C owner and unfortunately have to store my aircraft as a tie-down until I get off of one of the many hangar waiting lists I'm on. I have one of Macs covers ordered and should be arriving in the coming 1-2 weeks, but in the meantime I have noticed ongoing leaks during rain. I came to the plane today and found the carpets wet. Obviously I want to fix this asap and was wondering where the most likely sites of leaks would be. I have ordered new cabin door, baggage door, and vent window seals from K2U and will get those installed asap, but anywhere else I should be looking?

Thanks!

Edited September 11, 2018 by BrettKS
typo

[Guitarmaster]

Check the duct tape seal between the wing and the fuselage. there's a good chance that has deteriorated and water is running down the wing it into the cabin.


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[BrettKS]

18 minutes ago, Guitarmaster said:

Check the duct tape seal between the wing and the fuselage. there's a good chance that has deteriorated and water is running down the wing it into the cabin.


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Is this best assessed from the underside where the wing attaches to the fuselage? In the photo it appears that the wing is detached, right? Is it possible to redo the tape without detaching the wing?

 

[takair]

You can try DC4 or even petroleum jelly on the door seal as a temporary seal.  The avionics hatches are the usual suspect and there are various ways of sealing them.  The cover should help, but RTV is the easiest short term.  Check the vent window seal and the windows themselves too.

[Marauder]

The usual leak culprits are the overhead vent, the wing root seal (GuitarMaster’s reply), the door (Takair’s response) and the windows.

For the wing root, a MSC told me the best way to fix that is to remove the fairing, remove the old duct tape and use Gorilla heavy duty tape layered like roof shingles and then apply a bead of ProSeal over the tape: https://www.aircraftspruce.com/catalog/appages/ps890.php?gclid=EAIaIQobChMI492r1Ye03QIVRWx-Ch11tAu7EAQYAiABEgJVdPD_BwE

I would look really close at the seals around the windows. It’s possible for them to leak there in addition to the vent seal. Also, if any of the windows have cracks in them, it could wick water in. Either replace the window or use a clear Gorilla glue on the window (both inside and outside) until you can replace it.

I would also open the roof vent if you have one and see if running water into the vent shows up at the drain holes on the bottom. You could have a leak in the plenum and it is coming down behind the side panels or leaking out the drain line itself.



On my F, this line runs along the pilot side and down by the baggage area. You can see the tube at the back of the baggage area in this photo.
















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[Prior owner]

A Poorly sealed overhead antenna will also leak. 

[carusoam]

 

Brett add some data to your avatar area... It will help the people trying to help you.

 

Expect the overhead vent to drop a fair amount of water inside... (Marauder pics)

It has a drain tube that probably got old a couple of decades ago... find where the drain tube exits, and you will know how well it is working....

Most holes overhead are in the tail section.  The anti-collision light has a large possibility of being a leaker. My M20C never had a seal for that...

While you are waiting... Go to Home Depot before they run out of tarps!

Go with functionality over form, until your cover comes in...

Also be extra diligent with the fuel caps... until you really know how well they are keeping rainwater out...

PP thoughts from my outdoor M20C days... about a decade’s worth...

Also, Make sure your cover extends all the way forward over the instrument access panels... and all the way back to make sure the baggage door gets covered....

Stay dry and Best regards,

-a-

[Guitarmaster]

On 9/11/2018 at 5:53 PM, BrettKS said:

Is this best assessed from the underside where the wing attaches to the fuselage? In the photo it appears that the wing is detached, right? Is it possible to redo the tape without detaching the wing?

 

No, not detached.  That is the gap between the fuselage and the wing. IT is under the fairing and sealed with duct tape.  
I told my wife I had to duct tape the wing back on after a maintenance project; who's ready to go for a flight? 

[Prior owner]

I assume you guys are using foil tape, and not duct tape when replacing the wing root seal? Or have you found a duct tape to use without any cloth in it?

[N201MKTurbo]

Get in the plane and have someone run a garden hose over it and see where it is leaking from. 

Im betting on the door seal. Most of the other leaks will drain into the belly and run out the drain holes. Except for the old avionics bays, which are easy to seal.

[Piloto]

Long time ago when I had an M20C and no hangar found that the wet carpet leaks are due to rain leakage through the front access panels in front of the windshield. Sealed this panels with silicon seal and problem solved.

José

[BrettKS]

7 hours ago, N201MKTurbo said:

Get in the plane and have someone run a garden hose over it and see where it is leaking from. 

Im betting on the door seal. Most of the other leaks will drain into the belly and run out the drain holes. Except for the old avionics bays, which are easy to seal.

Will do. I confirmed the baggage door was likely a major contributor. Got that sealed with a Knots2U seal today and plan to test it with a garden hose once it sits for a bit. I also used some RTV to seal the front cowl area where the avionics related leaks are mostly originating, need to test this area as well.

On 9/13/2018 at 7:57 PM, Guitarmaster said:

No, not detached.  That is the gap between the fuselage and the wing. IT is under the fairing and sealed with duct tape.  
I told my wife I had to duct tape the wing back on after a maintenance project; who's ready to go for a flight? 

Interesting. I'm still not totally sure where this duct tape is, but I'm going to go to the plane this weekend with your photo and see if I can figure out what you mean.

On 9/11/2018 at 8:45 PM, carusoam said:

 

Brett add some data to your avatar area... It will help the people trying to help you.

 

Expect the overhead vent to drop a fair amount of water inside... (Marauder pics)

It has a drain tube that probably got old a couple of decades ago... find where the drain tube exits, and you will know how well it is working....

Most holes overhead are in the tail section.  The anti-collision light has a large possibility of being a leaker. My M20C never had a seal for that...

While you are waiting... Go to Home Depot before they run out of tarps!

Go with functionality over form, until your cover comes in...

Also be extra diligent with the fuel caps... until you really know how well they are keeping rainwater out...

PP thoughts from my outdoor M20C days... about a decade’s worth...

Also, Make sure your cover extends all the way forward over the instrument access panels... and all the way back to make sure the baggage door gets covered....

Stay dry and Best regards,

-a-

Added some data to my avatar. Thanks for the good summary here. Will keep your thoughts in mind. I did test out the overhead vent tubing system and didn't see any leaks.

On 9/11/2018 at 6:10 PM, Marauder said:

The usual leak culprits are the overhead vent, the wing root seal (GuitarMaster’s reply), the door (Takair’s response) and the windows.

For the wing root, a MSC told me the best way to fix that is to remove the fairing, remove the old duct tape and use Gorilla heavy duty tape layered like roof shingles and then apply a bead of ProSeal over the tape: https://www.aircraftspruce.com/catalog/appages/ps890.php?gclid=EAIaIQobChMI492r1Ye03QIVRWx-Ch11tAu7EAQYAiABEgJVdPD_BwE

I would look really close at the seals around the windows. It’s possible for them to leak there in addition to the vent seal. Also, if any of the windows have cracks in them, it could wick water in. Either replace the window or use a clear Gorilla glue on the window (both inside and outside) until you can replace it.

I would also open the roof vent if you have one and see if running water into the vent shows up at the drain holes on the bottom. You could have a leak in the plenum and it is coming down behind the side panels or leaking out the drain line itself.



On my F, this line runs along the pilot side and down by the baggage area. You can see the tube at the back of the baggage area in this photo.
















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I found this tubing from the overhead vent and visually didn't see any leaks. Hopefully this isn't a contributor.

On 9/11/2018 at 5:57 PM, takair said:

You can try DC4 or even petroleum jelly on the door seal as a temporary seal.  The avionics hatches are the usual suspect and there are various ways of sealing them.  The cover should help, but RTV is the easiest short term.  Check the vent window seal and the windows themselves too.

Thanks! Yes, baggage door was at least one of the culprits. Replacing the seal for the cabin door and window vent this weekend.

[BrettKS]

So cover is in, which is great. Interior is no longer getting wet at all. I'm curious about the potential for leaks on avionics from the area just forward of the windshield. If there was a leak here, where would I be able to detect water coming in? Would it drip on the avionics then fall to the carpet under the dash?

 

Thanks

[Hector]

So cover is in, which is great. Interior is no longer getting wet at all. I'm curious about the potential for leaks on avionics from the area just forward of the windshield. If there was a leak here, where would I be able to detect water coming in? Would it drip on the avionics then fall to the carpet under the dash?
 
Thanks

My cover extends forward of the windshield sufficiently to cover the avionics access panels. If it leaks there then yes, it will drip down on your avionics boxes and unto the carpet. Not good at all. Does your cover extend forward of the windshield?


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[BrettKS]

46 minutes ago, Hector said:

 

My cover extends forward of the windshield sufficiently to cover the avionics access panels. If it leaks there then yes, it will drip down on your avionics boxes and unto the carpet. Not good at all. Does your cover extend forward of the windshield?


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Yes, my cover does extend over the area to cover the avionics access panels. I'm just trying to convince myself that it isn't leaking there based on the fact that I had no evidence of water on the carpet under the avionics or moisture in that area before I got the cover. Ideally, I'd like it to be water proof in the rain without the cover