Elevator trim tubes wear

[Sean S]

1975 M20F, manual trim. The forward and mid tubes have wear on them from contact with the bulkhead cutouts.  I am replacing them both, and noted a good but of play that I believe will just cause the same problem again. Is this play normal or is my plane missing some blocks or something to minimize this play. Quick video and photo attached.IMG_0761[1].MOV

[Guest]

I can't get your video to play, however there is always quite a bit of play between the tube and the plastic bushing.  In many cases the wear sleeve moves allowing the aluminum to contact the bushing causing the wear. 0.007" is the max depth of wear.

Lack of grease and cleaning like yours are quite common.

Clarence

[Sean S]

Hi Clarence, thanks for the reply. If understand you correctly, there is supposed to be a wear sleeve on the tube? Thanks also for the wear limits. I am fairly certain I am beyond that.

[N201MKTurbo]

You have a wear sleeve on your tube, I can see it in the picture. It is like tape on the tube. Yours is worn away at the contact point. Also check your bushing it is probably worn away too so there is metal to metal contact between the tube and bulkhead.

it only takes a minute at annual to wipe the old grease off with a rag and dab some new grease on with your finger. If you do this they will last forever.

[Guest]

Look up SB M20-185 it has more info on the trim tubes.

Clarence

[carusoam]

Bayern,

Please post your video using YouTube if you can...

It is Google's way of getting around Steve Job's stronghold.  

Best regards,

-a-

oops, just accidently posted a day old post... solutions have been posted already...  maybe next time. 

[Sean S]

I will post up a video to YouTube and link it here later. Agreed I have a good solution already, thanks!

[MyNameIsNobody]

How many hours on your airframe?

[mike_elliott]

Pretty common on the older vintage planes to have the trim tube neglected, especially at the bulkhead back by the radio rack. Clarence referenced a SB where Mooney at one time was providing the parts to do this., Not so much now. In any event, this is one of those annual and prebuy items a non Mooney Savvy IA will miss. It doesnt take much to put some UHMW tape around the trim tube to help "protect" it, but as has been said, annual maintenance is the key to not spending upwards of 4 amus on a stinkin' aluminum tube. The play is normal, it is not supposed to be tight

[Sean S]

17 hours ago, MyNameIsNobody said:

How many hours on your airframe?

Around 3300 hrs.

[Sean S]

Here is the video. As mentioned above, this play is normal, the wear groove if greater than .007, is not normal. You should also expect to finde polyurethane anti chafe tape at the contact point.

 

[Guest]

14 hours ago, mike_elliott said:

Pretty common on the older vintage planes to have the trim tube neglected, especially at the bulkhead back by the radio rack. Clarence referenced a SB where Mooney at one time was providing the parts to do this., Not so much now. In any event, this is one of those annual and prebuy items a non Mooney Savvy IA will miss. It doesnt take much to put some UHMW tape around the trim tube to help "protect" it, but as has been said, annual maintenance is the key to not spending upwards of 4 amus on a stinkin' aluminum tube. The play is normal, it is not supposed to be tight

Budget annuals don't always include maintenance, these pages are full of examples.

Clarence