Elevator Movement/Yoke Bushings

[885EW]

M20S. During preflight, the elevator would bind/stick in the level pitch position (a lot more prominent in the hotter temperatures for some reason).  A slight amount of force would get past the stick and also same issue when I moved the elevator via the yoke as well. Mechanic said the yoke bushings are the issue causing the yoke to bind at that spot. Lubrication on the yoke shafts seems to have fixed the issue temporarily; but we have ordered new yoke bushings to be installed. Any one else have similar issues in the past and found this to be the culprit? Thanks

[885EW]

Photo for reference at position where it sticks/binds.

[Ragsf15e]

28 minutes ago, 885EW said:

M20S. During preflight, the elevator would bind/stick in the level pitch position (a lot more prominent in the hotter temperatures for some reason).  A slight amount of force would get past the stick and also same issue when I moved the elevator via the yoke as well. Mechanic said the yoke bushings are the issue causing the yoke to bind at that spot. Lubrication on the yoke shafts seems to have fixed the issue temporarily; but we have ordered new yoke bushings to be installed. Any one else have similar issues in the past and found this to be the culprit? Thanks

Do you mean the “plastic/nylon” bushing through the panel?  If so, yes, those can do exactly what you said.  Initially mooney recommended cleaning and oiling them lightly, then they recommended just cleaning them as lubricants attracted more dirt.  @PT20J changed his if i recall.

[Flyler]

I'm not sure if this translates to Mooney, but in the school/rental Piper, those yoke bushings were very worn out.  I could test the yoke bushing by side loading it.  If you pull back with one hand, or slightly push the yoke laterally as you move it in and out, and the problem gets a lot worse... suspect that bushing.  Flying with both hands made the yoke move in and out smoothly.  Of course, I always have my hand on the throttle during takeoff/landing so it was still an issue.

[Ragsf15e]

1 hour ago, Flyler said:

I'm not sure if this translates to Mooney, but in the school/rental Piper, those yoke bushings were very worn out.  I could test the yoke bushing by side loading it.  If you pull back with one hand, or slightly push the yoke laterally as you move it in and out, and the problem gets a lot worse... suspect that bushing.  Flying with both hands made the yoke move in and out smoothly.  Of course, I always have my hand on the throttle during takeoff/landing so it was still an issue.

That “stick-tion” also has implications for the autopilot.  Some of the initial “hunting” in level flight by the gfc500s was eliminated by fixing the bushing (or cleaning it really well).

[dkkim73]

From what vantage do you best see those bushings? At the MPPP, Rob mentioned having access via a side panel on the center console. Is that it? Or maybe just crawling underneath?

[PT20J]

Wow. It would seem to take a lot of friction to stick long body elevator in that position since it has both a down spring and a bob weight. Anyway, buy some new eyeball bushings from Mooney and don't lube them. They are difficult to install because you have to remove the yokes and the shafts. 

[Pinecone]

I had mine changed when I did the avionics.  Easy with the panel off and most things removed.

[885EW]

Thanks for the feedback so far everyone. We have lightly lubricated the shafts as a temporary fix until the yoke bushings come in (should be fairly soon). Seems to be a solution so far. Elevator/yoke has the slightest ounce of friction at that position still but no where close to the issue presented before. 
 

From those who have done this in past, in your opinion; is the lubrication temp fix deemed airworthy or should airplane stay on ground until new bushings arrive? 

Edited Wednesday at 03:49 AM by 885EW

[Bartman]

You cleaned the shaft, lightly lubricated it, and stated it seems to be a solution.  After lubricating hemi joints and ensuring nothing is causing binding of the push/pull tubes to the tail, I would not hesitate to fly.

[Flyler]

7 hours ago, 885EW said:

Thanks for the feedback so far everyone. We have lightly lubricated the shafts as a temporary fix until the yoke bushings come in (should be fairly soon). Seems to be a solution so far. Elevator/yoke has the slightest ounce of friction at that position still but no where close to the issue presented before. 
 

From those who have done this in past, in your opinion; is the lubrication temp fix deemed airworthy or should airplane stay on ground until new bushings arrive? 

I know a worn out Piper school plane isn't the best comparison, but ours has been awfully sloppy for about 2 years and there's simply a can of Silicone spray sitting in the baggage compartment.  In my plane, I would not think it much of a safety issue but the annoyance of it would drive me to replace the bushing very quickly.  

[Fritz1]

in order to clean the bushings it is best to take the two bolts out that hold them in the panel, then wiggle and clean with contact cleaner over and over again, the ball can wear out and get wedged which causes the binding, most of the time cleaning the ball and the shaft solves the problem, taking the yoke shafts out is a lot of work, cleaning is easy by comparison, lubing with any oil attracts dirt, robbing Peter to Pay Paul, anybody tried dry graphite lube?

[PT20J]

The eyeballs are machined from Nylatron according to Frank Crawford. Even the new ones are not perfectly smooth due to the machine marks. Oil film attracts dirt that becomes embedded. I didn’t have much improvement in mine doing what @Fritz1 suggested, but it can’t hurt to try. It might be interesting to try spraying them with some boron nitride dry film spray. That stuff is really slippery.  

[Fritz1]

boron nitride dry film spray, interesting, feels good to be in touch with people who know stuff!

[N201MKTurbo]

15 hours ago, PT20J said:

The eyeballs are machined from Nylatron according to Frank Crawford. Even the new ones are not perfectly smooth due to the machine marks. Oil film attracts dirt that becomes embedded. I didn’t have much improvement in mine doing what @Fritz1 suggested, but it can’t hurt to try. It might be interesting to try spraying them with some boron nitride dry film spray. That stuff is really slippery.  

   I have always been a fan of molybdenum  disulphide. It works great, but it is black and insoluble in anything normal. If you get it on your clothes, it will be there forever. How is BN in that respect?

[Hank]

2 minutes ago, N201MKTurbo said:

   I have always been a fan of molybdenum  disulphide. It works great, but it is black and insoluble in anything normal. If you get it on your clothes, it will be there forever. How is BN in that respect?

Moly disulfide is a great grease, but aside from the immediate permanent stains on anything it touches, if used on the yoke (or any unsealed area) it will attract dirt, dust and anything floating by. I've used it a lot at work, and am a big fan, but it's not for my Mooney. 

[PT20J]

1 hour ago, N201MKTurbo said:

   I have always been a fan of molybdenum  disulphide. It works great, but it is black and insoluble in anything normal. If you get it on your clothes, it will be there forever. How is BN in that respect?

The BN I used came from a friend who got a sample can somewhere and is white and powdery. I haven't used this product, but it looks interesting https://www.performancelubricantsusa.com/product-page/dupont-non-stick

[natdm]

Not sure if it applies here too but mine (M20K) would do this from time to time and I took off the inspection panels on the bottom of the body and realized one of the screws for the panels was too long and was wearing a mark in to one of the push-rods. I just keep the screw out and it works fine now (after IRAN the rod). Maybe check for that too?

[Ethan]

I had the same frustrating problem with my Mooney 231. To try and fix the problem, I cleaned the eyeball bushings lubricated them with triflow, silicone, etc. Nothing worked until I bought two new yoke shafts. The new ones are a slightly smaller diameter and have a different - non-chromed finish - it worked, no more sticking. It was expensive but worth it. 

[PT20J]

On 6/26/2025 at 10:34 AM, PT20J said:

The BN I used came from a friend who got a sample can somewhere and is white and powdery. I haven't used this product, but it looks interesting https://www.performancelubricantsusa.com/product-page/dupont-non-stick

I ordered some of this from Amazon, but the stuff they sent is teflon, not ceramic (boron nitride).