Overhead vent failure 1964 M20C/M20D

[jt_flyer]

I just pruchased an M20D what converted to an M20C. The overhead fresh air vent is not operating properly. After remove the headline it appears the cable has disconnected at the door. The knob side cable is connected and appears to move when the knob is rotated.  I'd like to reconnect or replace this cable however there doesn't appear to be a way to remove the water tight aluminum enclosure around the vent to access the cable termination/vent mechanism without removing the rivets that hold this enclosure to the top of the fuselage.  Am I missing something?  Is there a way to access this cable end without removing rivets?  Thanks. 

[cctsurf]

Mine is still connected,  but needs help moving...  I'd love to know how to do this as well...  I've looked at the diagrams, but I haven't dug into it.  Bigger fish to fry.

[bonal]

Welcome to MS and as always post some pics of your new pride and joy. When we got ours the vent was inoperative and during annual we found the cable disconnected at the vent. My AP did a simple reconnect and it works fine sadly I did not see it done as I was attending to other things on the airplane at the time. All I can add is there was no need to remove any rivets to access the connection. Hope you can find as simple as I did.

[TonyK]

Mine is ground adjustable only at the moment.  It hasn't been high on my list since the ice just went out on the lakes.

 

[carusoam]

Getting the maintenance manual would probably get you the drawings that you need...

That area is the least well known by us owners because it hides behind the ceiling that takes hours to remove and put back.

While you are in there. The cable operation should be checked, cleaned and lubricated. Whatever it takes to make the control work. The other thing that never works right after decades is the drain line for the box. Swap out the drain line...

Mooney was pretty good back in the 60's for not requiring an owner to take rivets out for ordinary maintenance if they didn't need too.

trying to be encouraging while not having a direct answer...

PP thoughts only, not a mechanic.

Best regards,

-a-

Edited April 8, 2017 by carusoam

[TTaylor]

In general these can be repaired without removing any rivets.  It is helpful if you are proctologist or have similar skills .  Remove all the headliner and parts that you can. You may need some forceps or similar tools to get the cables or rods into the correct locations.  It is a good idea to clean and lube the cables, rods, gears and parts as part of the process. It is helpful to have two people so one can help move the vent on the outside whiles move the knobs on the inside to free up stuck vents.  Usually the reason a cable gets disconnected is it requires too much force to open the vent.  Cable problems are usually symptoms of other problems such as the hinge or gears need lubrication.

This one on eBay may be similar to yours to give you a better idea of the parts: 

http://www.ebay.com/itm/Mooney-M20C-roof-vent-mechanism-Overhead-Interior-Trim-Piece-For-Lights-Vents-/151594613447?hash=item234bbe3ac7:g:x1MAAOSwBahU1o3n&vxp=mtr

Tim

[Andy95W]

You cut a hole in the bottom of the air box and make a patch for it.  I sealed mine with blue RTV.  See photo.

[jt_flyer]

Thanks very much for your comments.  Great resource for new mooney owners like me.  First time flying a mooney.  I can say already... I get it. . 

[Raptor05121]

Mine is also broken. Makes a loud "POP" on runup and takeoff when the wind catches it, sounds like a backfire. Makes first time passengers very nervous.

[rbridges]

3 minutes ago, Raptor05121 said:

Mine is also broken. Makes a loud "POP" on runup and takeoff when the wind catches it, sounds like a backfire. Makes first time passengers very nervous.

Mine is pretty smooth but then clicks pretty loud 3 times before closing 100%.  I'm not sure what's going on but I figure it's just a matter of time. 

[Hank]

2 hours ago, rbridges said:

Mine is pretty smooth but then clicks pretty loud 3 times before closing 100%.  I'm not sure what's going on but I figure it's just a matter of time. 

Cable Dressing! Apply liberally from the top and run it up and down. If you open up the ceiling, apply at the other end, too.

[Nokomis449]

My '68G vent looks a little different, but I had the cable break in flight several years ago.  Made the loudest bang as it went from barely cracked open to slamming against the fuselage at 170mph.  Sounded like somebody hit us with a sledge hammer at 6k ft.  Luckily I was southbound in late afternoon, and the shadow of the vent fell across the left wing.  I couldn't tell exactly what was wrong, but knew the shadow wasn't right.  Overflew the FBO guys just to verify I still had 3 tires, and after landing saw the vent was folded back like a sardine can.  Anyway, the wire had broken at the vent and couldn't be salvaged, so the mechanic replaced the wire.  The important thing to know is that you can replace the wire without having to replace the entire thing - cable, cable shroud, etc.  Makes it a 1 hour job instead of a 1 day job.  Good luck!

[N6758N]

The cable can be replaced without removing the entire vent assembly. You need to order stainless steel wire from aircraft spruce to replace it. The housing (or sheathing) for the cable can remain in place and you can simply slide a new cable in.