M20C Landing Gear kickback

[Paul - M20C]

My landing gear springs back about 1/4" after full down. Anyone seen this and know what causes it? My A&P brought in an expert and they re-rigged everything but it still does it. The current thought is that the actuator may need replacing or the gears. Looking for your experiences.  Thanks.

[gsxrpilot]

Does this C have electric gear? And I'm naturally suspicious of the "expert".

[Browncbr1]

Is that not the nature of over center links?

[Paul - M20C]

1 hour ago, gsxrpilot said:

Does this C have electric gear? And I'm naturally suspicious of the "expert".

Yes it does have electric gear.

[N201MKTurbo]

What exactly do you mean by kicks back?

[Tcraft938]

I'm not sure if this will help you, but here is a gear swing video on youtube.  There are many others to chose from as well.    Best of luck with it, I hope it works out for the better.

 

[Hank]

45 minutes ago, Tcraft938 said:

I'm not sure if this will help you, but here is a gear swing video on youtube.  There are many others to chose from as well.    Best of luck with it, I hope it works out for the better.

 

Yep, that's mine from 2 years ago. My now retired IA is short and had a hard time reaching the switch from outside.

[Tcraft938]

2 minutes ago, Hank said:

Yep, that's mine from 2 years ago. My now retired IA is short and had a hard time reaching the switch from outside.

The manual bar would have been a killer for him.  LOL

[Paul - M20C]

The video below shows the gear retraction and extension.  It's kind of hard to see in this video but it's a lot more pronounced than the videos above.  I will post a video of the gear motor next and you'll really see what I mean.  It's that last second where the gear motor actually reverses.

https://youtu.be/nw9rYPy7LZo

Edited January 13, 2020 by Paul - M20C

[Paul - M20C]

Close up of the gear motor during swing test.  When the gear goes up it looks fine but when it goes down it finishes and then the motor reverses for a second.

https://youtu.be/iklbnun4VhA

[ArtVandelay]

I would check the down limit switch for proper functionality, there is normal close and normally open terminals, make sure both are working as designed, and make sure switch is properly secure.

[Guest]

On 1/12/2020 at 12:26 PM, Paul - M20C said:

My landing gear springs back about 1/4" after full down. Anyone seen this and know what causes it? My A&P brought in an expert and they re-rigged everything but it still does it. The current thought is that the actuator may need replacing or the gears. Looking for your experiences.  Thanks.

There are a number of crucial service bulletins on your gear transmission.  They are free on www.mooney.com Best to familiarize your self with them.

The 20:1 gears in your transmission are subject to wear when not greased properly.

Clarence

[N201MKTurbo]

In the video it is back driving the actuator. How are your preloads after it back drives? How do your spring compressions look? I have a feeling you are overdriving the gear, but I can't tell unless I'm there. 

If you use the crank until the light comes on does it want to back drive? Does it get hard at the end?

[Paul - M20C]

All good questions. My A&P/IA is a Mooney Service Center and he's following along on this. I appreciate the advice and questions 

[Andy95W]

This almost kind of reminds me of an issue I had 25 years ago with my first M20C with electric gear.  I called up Dugosh and spoke with the owner at that time, Ronnie.  He said that the tensioner/friction springs inside the motor were old and no longer holding the motor from spinning when the motor wasn't energized.  

I took my motor to him, he disassembled it and installed 2 standard AN 960-10 washers as shims to make up for the springs that had lost some of their tension.  Worked great.  And he wouldn't let me pay him.  He was a great guy, hope the new Dugosh owners are similar.

[SheryLoewen]

Service Bulletin SBM20-177

[Andy95W]

@Paul - M20C

Just curious what resolved your issue.  There is a current thread that is a little similar to yours 3 years ago.  Thanks!