Overhead Ventilation System Air Deflector Removal -M20J

[squeaky.stow]

While I am at it, the leather trim rings around the vents look a little wrinkled and shabby. Any ideas on what I could replace them with? A nice aluminum or plastic bezel would look nice but I have no idea how I would get one made with the right concave shape.

[carusoam]

Looks like something a classic auto interior shop might have an answer for....
 

Some people have experimented with 3D printing, and fabric coverings....

Looks like it may take one part Engineering and one part artist to make a full solution...

There is a leather shop in TX that may be able to help... they are familiar with Mooney interior details...

Best regards,

-a-

[Lwebb1952]

On 3/30/2020 at 2:43 AM, rrbeck11 said:

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!!

 

 

Rrbeck11.  How did you manage to install the new deflectors once the old ones were removed?  

[rrbeck11]

2 hours ago, Lwebb1952 said:

Rrbeck11.  How did you manage to install the new deflectors once the old ones were removed?  

Lwebb - see the stackup in the photo above. Knurled knob, deflector, ( washer? Can’t remember), plate.  don’t forget the set screw that holds the plate to the knurled knob. I’d recommend a drop of Loctite (the non-permanent kind). You don’t ever want to do this again.

 Hold that assembly up to the hole in the plenum, then use a skinny needle nose to set first the big washer then the small one on the end of the threaded shaft. Use a piece of duct tape over the end of a box wrench to hold the nut in place. Slide the wrench between the deflector and the plenum then start turning the knurled knob until it threads. After several turns the plate will hit the stop (a tiny set screw pointed down from inside the plenum). At this point it’s 1/6 turn, then reposition the wrench, then 1/6 turn until you are happy with the friction. To loose and it will rattle. Too tight and you just broke something.  Take your time - it’s real easy to break out the set  screw or crack the 44-year-old plenum (Voice of experience). 
 

If you’re still stuck PM me with a phone number and I’ll talk to you down.

good luck,

Randy

[Lwebb1952]

On 5/10/2022 at 1:40 PM, rrbeck11 said:

Lwebb - see the stackup in the photo above. Knurled knob, deflector, ( washer? Can’t remember), plate.  don’t forget the set screw that holds the plate to the knurled knob. I’d recommend a drop of Loctite (the non-permanent kind). You don’t ever want to do this again.

 Hold that assembly up to the hole in the plenum, then use a skinny needle nose to set first the big washer then the small one on the end of the threaded shaft. Use a piece of duct tape over the end of a box wrench to hold the nut in place. Slide the wrench between the deflector and the plenum then start turning the knurled knob until it threads. After several turns the plate will hit the stop (a tiny set screw pointed down from inside the plenum). At this point it’s 1/6 turn, then reposition the wrench, then 1/6 turn until you are happy with the friction. To loose and it will rattle. Too tight and you just broke something.  Take your time - it’s real easy to break out the set  screw or crack the 44-year-old plenum (Voice of experience). 
 

If you’re still stuck PM me with a phone number and I’ll talk to you down.

good luck,

Randy

Thanks for the Reply Randy.  My 78 20 J didn’t have the set screw.  To install,  I ended up cutting about a 2 in oblong hole in the plastic duct at each location, aft the front deflectors at the two front deflectors at the front deflectors and on the side of the rear deflectors in line with the screw knobs.  I installed the two washers above the damper, then made sure they were aligned with the hole with a appropriate sized Phillips screw driver, then pushed up the deflector assembly.  I then used a wrench with tape, like you, to hold the 3/8 nut.  The damper stops, which are screws, I twisted step back up into the duct, leaving just enough that I could still turn them back out with needle nose pliers after the deflector was installed.  With the wrench I place , I used the knob to tighten the assembly, then used the needle nose pliers to twist the stops back out.  On one of the deflectors I made the hole slightly too large where it slips on the knob. I was able to solve the issue by using an appropriate oRing size.  Thanks for the lead on Plane Plastics as a source for the PMA deflectors!

 

 

 

[trevttu76]

I am getting ready to tackle this, and not looking forward to it...

I have a 78 model, I do not see any setscrew on the knob.  I can see a "screw" pointing down that match the description of LWebb1952.   (pic of my assemble attached)

Thinking that cutting a hole in the aft part of the plenum and then patching that piece might be less difficult than getting a wrench through the small opening and angle between the plenum and the deflector.  The white deflector I have is so brittle looking at it wrong results in a piece falling off.  I am worried that trying to get a wrench between the assembly would break the plenum.  

I am looking at the Plane Plastic replacement louver piece, and I also see that Jaeger offers a swap to eyeball vents for the same cost (pic in thread).  Appears that you must cut out the entire piece and then install the oversize plastic to fill the hole in the plenum.  

Has anyone replaced their louver with the Jaeger eyeball vents (wemac)?  

 

Any other words of wisdom before I make a huge mistake!?  

[carusoam]

Many 3D printed boxes with wemacs lately…

-a-

[rrbeck11]

trevttu -

There's some confusion in this thread about the set screw.  The set screw I referred to previously is the one attaching the air valve (nuclear symbol-looking plate) to the cabin roof side of the knurled knob (see the small screw next to the threaded end of the knob in the photo below):

You won't see that screw until you've removed the deflector/air valve by loosening that nut. 

As far as cutting holes/patching: you're replacing those old brittle deflectors, right?  So if they break, no problem.  You do have to be careful not to put pressure on the plenum, but if you go slow and careful, it can easily be done.  I'd suggest reading my March 2020 post carefully and give it a shot before you cut any holes. 

Btw, once you've got the assembly sitting on your glareshield, you'll notice two small screws up in the plenum with the pointy ends down.  Those are stops for the air valve.   If you go with Plane Plastics or other deflectors, keep them.  For a wemac you can ditch them. 

If you are going with Plane Plastics or other oem-looking solution, a little duct tape on the end of your wrench to hold the nut in place when you try to re-tighten works wonders!

 

Good Luck!
 

Edited November 21, 2022 by rrbeck11

[trevttu76]

I finished this part of my project, and to be honest it was not as bad as I assumed. 

I ended up replacing all 4 of my existing with new ones from plane plastic.  The fit was fine, but I was not 100% happy with the design on their replacements.   The "holes" that direct the air in the new plastic louvers point in opposite directions (factory all direct air the same direction).  Since the front vents need all the air focused to cool the passengers, this isn't optimal...  Other than that the quality and durability/flex of the new ones is good.  Of course for $50 each I would have hoped for a better design or match to the OEM.

If someone is hesitating tackling this, don't sweat it.  I would however plan on replacing any louvers you remove , I don't think the old fragile vents would survive removal and re-assembly as there is some flexing in the process.  

Thanks for the tips in this thread, made the unknown a little better.