Overhead Ventilation System Air Deflector Removal -M20J

[txmooney201]

Does anyone have any experience removing the round vent air deflectors located on the cabin ceiling?

I am refreshing the interior in my J model and need to remove all 4 of them to paint them. I have the ceiling panels removed but don’t see and way to remove the deflectors. Thanks!

[N201MKTurbo]

It is a real PITA.

Remove the knob assembly then stick a 3/8 end wrench in there. There is a nut on top of the spiny thing. Get the wrench on it and rotate the silver knob to un screw it. If you tweak it around a bit you can get the deflectors to rotate beyond their stops so you can unscrew it. Good luck, don't cuss too much.

[Hank]

Look closely at the knob, there's a set screw in the side of it that requires a tiny Allen wrench. Then proceed as above.

[txmooney201]

Thanks guys! I will look for the tiny set screw in the knurled knob. It seems like the knob is what is holding the deflector up in the duct. This is a 1978 model so it is pre-NACA duct. Thanks Again!!

[jetdriven]

I replaced them with this :

[N201MKTurbo]

I replaced them with this :image.jpg

I replaced mine with Wemac eyeballs...

[jetdriven]

That's the preferred solution but it's a grand extra for 4 of the larger size ones.

[TWinter]

Byron, Where did you get those? Looks great.

[jetdriven]

2005 Chevy Tahoe. Set of 4 on eBay for 30$, plus the fabrication of the piece they fit into (the cabin skin won't clear the mechanism behind the vent without being raised like that.

[N201MKTurbo]

I got the four Wemacs on EBay from someone who was parting out a King Air for $5.00 each!

[Randy_B]

If you are talking about the small round aluminum eyeball vents, they are tough.  In my 84" J the vents are part of an assembly that is glued to the backside of the two ceiling panels.  I recently removed mine to install new ceiling panels.  It took some careful cutting and trimming to prepare them for installation onto the new panels.

[rrbeck11]

Hey folks!  Hope you are all making it through the isolation in our new world  I have the same problem as the OP. ‘78 M20J. No set screws on my knurled knobs. Anyone know how to get these off?  Next assembly is riveted through the top of the fuselage. REALLY don’t want to go there...

I’ve got four of the OEM replacement parts from Plane Plastics. I’d like to go with that solution if possible. 
 

any help appreciated

Randy

[carusoam]

Randy,

There are reports above...

1) Set screw... if you don’t have one....

2) A nut further up the shaft... sort of hidden as well...

Expect a set screw to be needed to hold the knob in place on such a fine old piece of machinery....

Spring steel didn’t get used for knobs until much later on (in cars). in that case gently pull the knob off...

Let us know what you find...

Best regards,

-a-

[N201MKTurbo]

21 minutes ago, rrbeck11 said:

Hey folks!  Hope you are all making it through the isolation in our new world  I have the same problem as the OP. ‘78 M20J. No set screws on my knurled knobs. Anyone know how to get these off?  Next assembly is riveted through the top of the fuselage. REALLY don’t want to go there...

I’ve got four of the OEM replacement parts from Plane Plastics. I’d like to go with that solution if possible. 
 

any help appreciated

Randy

What I posted 5 years ago still works. 

Just pull down the edge of the plastic and aluminum and stick a 3/8 opened end wrench through one of the sector holes on the plenum. You will be able to engage the nut on top of the knob. Hold the wrench in place and rotate the knob to unscrew the nut. When the aluminum disk hits its stop just pull it down below the stop and keep unscrewing it.

[rrbeck11]

Thanks Gents  

I got all four deflectors off today, with help from your responses, prior posts and from Byron (thanks again,). Here’s what worked:

Remove headliner

Insert 7/16” box or open end wrench between the air plenum and the metal plate with triangle cutouts that is attached to the knurled knob.  There is no way to remove this knob without breaking the deflector as there is a screw accessible only from above that holds the plate to the knob. As mentioned above, there is no set screw (78 M20J). Your plane may be different. 
 

Grip knob with a Pair of padded vice grips (a nitrile glove works great).  You’ll only get 1/8th turn at a time until it’s loose enough for the plate to clear the stop pin, or as Rich suggests above, you can pull the plate (disk) down a little to clear the stop pin.  Caution is advised.  The plenum is riveted through the top fuselage skin and will be brittle on your 40+ year old treasure.  You don’t want to break that part!!

Here’s a look after removal  Note the countersunk screw that keeps the flow controller plate from spinning around the shaft.  

 

Thanks again for your help,  Team Mooniac!!

 

 

[carusoam]

Great follow-up rrb!

One interesting thing...

The air valve(?) (nuclear symbol looking device) in yours is sheet metal...  I believe the older ones may have been made of plexiglas... (?) my M20C fuzzy memory....

Best regards,

-a-

[Jim F]

I agree these are a PITA to deal with.  The Eyeball vents are glued in place. That said I was able to cut the assembly and reinstall the snap ring and a small dab of locktite on the snap ring.  There is not much room for other types of closable vents.  I used a small Dremal cutoff wheel, repaired the vent and then used the thinest ABS I could find to reglue with a scab patch. 
 

[PT20J]

On 3/16/2015 at 7:18 AM, jetdriven said:

I replaced them with this :

Byron -- those look really nice. I like them better than the eyeball vents in my '94 model. 

Realize this is an old post, but if you want to finish off the shoulder harness attachment try these. I got them through Fastenal. Same part as Mooney used.

https://www.caplugs.com/finishing-caps-rh?itemNumber=RH-20

Skip

 

[squeaky.stow]

On 3/31/2020 at 7:28 PM, Jim F said:

I agree these are a PITA to deal with.  The Eyeball vents are glued in place. That said I was able to cut the assembly and reinstall the snap ring and a small dab of locktite on the snap ring.  There is not much room for other types of closable vents.  I used a small Dremal cutoff wheel, repaired the vent and then used the thinest ABS I could find to reglue with a scab patch. 
 

Apologies for hijacking a thread about the older style vents.

@Jim F did your J come with the Wemac eyeball vents or were you replacing the old disk style vents? I have these Wemac vents in my 252 and the twist ring will no longer open and close the butterfly in the vent. It sounds like you were able to repair this without buying new vents. Any pointers? Also, mine appear to be seized in place, i.e. the ball does not swivel in the socket to direct the airflow. Is that the way they are supposed to be?

My headliner will be coming out in the fall for the installation of a Lynx active traffic antenna so I figure this is the time to get them fixed.

[PTK]

15 minutes ago, squeaky.stow said:

I have these Wemac vents in my 252 and the twist ring will no longer open and close the butterfly in the vent. It sounds like you were able to repair this without buying new vents. Any pointers? Also, mine appear to be seized in place, i.e. the ball does not swivel in the socket to direct the airflow. Is that the way they are supposed to be?

These need to be lubricated every couple of years occasionally. Spray some Triflow into them and work the twist ring back and forth. Also work the ball swivel in different directions. 

[squeaky.stow]

Thanks. That should solve the ball swivel part. It has not moved since I bought the plane so I wasn’t sure if it was fixed in place by design or by lack of maintenance. However mine are also clearly broken inside. I can see the u shaped slot and pin for the open/close mechanism and they are not connected. It appears that there is a snap ring inside that holds it all together that has either broken or fallen out. Hopefully just fallen out and still repairable.

[larrynimmo]

I cut the glue line out with a dremill tool with a thin diamond cutoff wheel...glued in with epoxy on the new ceiling....spray balls liberally with wd40 or silicone so if some epoxy gets on the ball it doesn’t stick.

this was among the very easiest part of changing out the headliners

Edited August 4, 2020 by larrynimmo
Additional info

[Jim F]

1 hour ago, squeaky.stow said:

Apologies for hijacking a thread about the older style vents.

@Jim F did your J come with the Wemac eyeball vents or were you replacing the old disk style vents? I have these Wemac vents in my 252 and the twist ring will no longer open and close the butterfly in the vent. It sounds like you were able to repair this without buying new vents. Any pointers? Also, mine appear to be seized in place, i.e. the ball does not swivel in the socket to direct the airflow. Is that the way they are supposed to be?

My headliner will be coming out in the fall for the installation of a Lynx active traffic antenna so I figure this is the time to get them fixed.

squeaky.stow, yes what you see on my aircraft was stock.  The eyeballs should move easily so they are ether frozen from debris or the round clip is the back has jammed.  With the headliner out just place on a bench and cut with a dermal and a cutting disc.  I originally tried a to cut the glue line but the headline is so thin I was afraid of causing visual damage on the cosmetic side.  On top I could care less how they look, but they should function.  Once apart it will be obvious. My round clip had popped out of the grove.  I cleaned everything, used spray silicone on the eyeball as a lubricant and reassembled.  On the round clip I cleaned the groove and clip with contact cleaner and with the clip installed I put two drops of Loctite blue 242.  I cut the ABS(must be ABS) reinforcement plates and glued together.  Feel free to PM me if you want to talk more.  Jim

Edited August 4, 2020 by Jim F

[squeaky.stow]

Thanks Jim,

That sounds like something I can handle without too much adult supervision. Hopefully my ring clips have just fallen out and are not broken.

Mark

[squeaky.stow]

Up to the hangar today for a closer look. Sure enough, some silicone lubricant loosened up the eyeballs so that they now swivel freely. Looks like 3 out of four wemacs have had the retaining ring come out of the groove so everything is just jumbling around loose in there. Got some work to do removing contact cement residue as well. Somebody was a little messy when they covered my plastic headliner with ultra leather.

Too bad there is no way to remove these without cutting the headliner. Not great forward thinking in the design department. At least the parts all appear to be intact.