Battery Access Panel Dzus Fitting M20D

[Sven]

We have a Dzus fitting that's not behaving and it happens to be the foreword fitting and has caused two unscheduled landings. We'll obviously change both but any idea how this is done? Is there some special tool for this? It's a pressed flare that holds the fitting and keeps it from departing. I'm certain Mooney never thought 54 years later this would be an issue. Any explanation, advice and counsel is welcome.

-Sven

[Hank]

Yes, there's a special tool. If nobody else remembers what it's called (I've not had to use one yet), prowl around on Spruce, or call them or your favorite A&P.

[MooneyMitch]

It appears the retaining ring is missing.   

Yes, removal tool and replacement Dzus and all are available from Spruce.

M20D parts manual will show specific Dzus size to be the send on the door.   I believe it's a #6, but please verify in parts manual. 

I hope that helps.

I've always admired your D model restoration.

[carusoam]

Looks like 50 years of rust and wear have caught up on that one...

Definitely check the aircraft spruce catalog.

They have all the bits and pieces and tools for the fastener.

One part stays in the sheet metal. The fastener part requires a different tool to compress the spring.

the older Mooneys may have used both dzus and the other brand depending on what part of the cowl this is from.

The door over the battery and oil fill may be the other type...

Aspruce has good info on how to select the proper part dimensions too.

An old MM might have a part number for you. (Like Mitch covered above!) 

Does this part catch on a wire crossing in a matching piece? The matching piece is probably held in place with rivets...

Best regards,

-a-

Edited April 19, 2017 by carusoam

[MooneyMitch]

"Does this part catch on a wire crossing in a matching piece? The matching piece is probably held in place with rivets..."

Now that you mention this, I believe that's exactly what type of fastener is shown in Sevn's photo.   

Further inspection maybe required as possibly the catch wire is broken or defective.

My little Mini Mooney (MM) battery access door has one Dzus and one wire catching fastener.  

Please take a closer look Sven.  I believe carusoam is on to something here! 

[Hank]

Missed the "Battery Access Panel" part while looking at the photo. My cowl and avionics bay panel are held on by Dzus fitting; I have two rectangular snap fittings on the two small access doors on the cowling [one above the battery, and a matching one on the other side over nothing]. Just a model difference, C to D, or a model year difference [mine is 1970].

Good luck!

[Yetti]

I always enjoy reading descriptions about the dumaflachy that holds the reverbulating framulator

[MooneyMitch]

Just now, Yetti said:

I always enjoy reading descriptions about the dumaflachy that holds the reverbulating framulator

Oh.........you mean that thingy that holds that other thingy next that [whatever!] ?  Being a retired engineer myself, I completely understand that type of descriptive language.

[Hank]

1 hour ago, Yetti said:

I always enjoy reading descriptions about the dumaflachy that holds the reverbulating framulator

Just don't be denigrating our duflatchies! They're often more important than the thigamajig next to them . . . .

--A Flying Mechanical Engineering, BSME, MSE 

[Yetti]

Thingamajigs are common items and defiantly not PMA and have no business trying to hold a whatchamcallit to the stablesizer

[Sven]

Thanks for the replies. The fitting does catch (most of the time) a wire spring. The spring is fairly good shape and is held on by rivets. No problem there. It's just the fitting. I'll check Spruce for the Dzus (kinda sings, doesn't it?) but I was just wondering if anyone had firsthand experience with this fitting.

 

[carusoam]

My first hand experience is 15 years old...

That wire part is in good condition.  Much better than the other part.  The dzus at AS come in several forms.  The battery cover used a standard screw driver slot to open and close.  The oil level /fill used thumb ears to twist...  when they lose their retaining springs then they risk getting lost.

you should be able to buy the parts, and tools from AS. Having the old part and a way to measure it will be helpful.  The part number in the MM probably hasn't changed in 50 years. Get SS ones if you can.  This would change the part number.

AS has some really good technical people to talk with on the phone.  Somebody there will be the resident dzus expert.

Aaaah, the power of the flying retired engineers....

-a-

This will get you 90% of the way there...   http://www.aircraftspruce.com/search/search.php?s=DZUS+FASTENERS&x=0&y=0

Edited April 20, 2017 by carusoam

[Sven]

Just as a follow-up for those searching this topic in the future. I was able to use a Dremel with a thin cutting wheel and cut the Dzus fitting apart on the back side of the door. For the love of God wear safety glasses when doing this, please. I had a cutting wheel break in two a long time ago and hit me in the face. Always wear protection! Once the fitting was in two it easily popped out. I did not have the special flaring tool and I was impatient so, using the grooves in the Dzus fitting I managed to get the new fitting mostly through the hole. It was a simple matter of pressing hard with my thumb and it popped in. I did not make the hole bigger in this process and the fitting will not come out. I purchased a stainless Dzus fitting at Spruce with the part number FJ4-35SS. I installed two and they fit perfectly.

Here is th link to the fittings: https://www.aircraftspruce.com/catalog/hapages/dzus2.php

I also did something else. With the advice of our mechanic I purchased a new fuel sampler. Because our old sampler had a standard flat head screw driver fitting on it he urged is to use a Snoopy tool. We bought two off of eBay. I put one in the vice and separated the blade from the handle. I then replaced the flat screwdriver with the Dzus blade and we are in business! I've attached a couple photos of the new tool. I will probably include this tool mod as a new post since it worked out so well.

 

-Sven

 

 

[Raptor05121]

My D model is having the same issue. One of them no longer clicks close and just freely spins. time to replace!

I love how your plane has the factory scheme and says "Master"

I think I want some vinyl cut so I can add it to my cowling.

[Andy95W]

Alex- if you're going to replace yours, I suggest changing them to Phillips- head Camlocs. The bases rivet in the same holes as the dzus bases.  I'll try too take a picture of mine.

[carusoam]

Nice follow-up Sven!

Best regards,

-a-

[DonMuncy]

9 hours ago, Andy95W said:

Alex- if you're going to replace yours, I suggest changing them to Phillips- head Camlocs. The bases rivet in the same holes as the dzus bases.  I'll try too take a picture of mine.

I prefer the "flat" screw heads rather than the phillips. That way you can look and see they are all engaged by seeing that the screw slots line up.

[Andy95W]

On 7/15/2017 at 10:29 AM, Andy95W said:

Alex- if you're going to replace yours, I suggest changing them to Phillips- head Camlocs. The bases rivet in the same holes as the dzus bases.  I'll try too take a picture of mine.

Sorry it took so long to post this.  I used a #2 Camloc and standard base, which rivets in the same mounting holes as the original Dzus fastener spring.  Minor alteration, but needs a sign off in your logbook.

Here are some pictures, sorry the paint is starting to chip off mine.  I probably should change them out for stainless.