Play in yoke column

[Danb]

My yoke column seems to have excess play in it. The pilot side has some excess play up and down.

What fix is necessary 

[PT20J]

If nothing is loose, it might need a new eyeball (part just behind the instrument panel that the shaft goes through.  I bought two for about $150 each a year ago, so Mooney may have stock. 

[1980Mooney]

@Danb Mooney has been using the same "eyeball" or "donut" bearing on the same yoke shaft since 1977 on J through Ultra.  Parts diagram is from an Ovation. (see pic below of Ultra assembly)  I think it is a sintered bronze Oilite sleeve bearing.

Make sure that your yoke shaft is smooth - no imperfections or corrosion. To replace the sleeve bearing you have to remove control handle, disconnect the shaft and carefully remove the wiring on one end.(radio tap to talk switch, pitch controls, etc) in order to get the old bearing off and the new one on.

 

Edited February 21, 2022 by 1980Mooney

[Joshua Blackh4t]

55 minutes ago, 1980Mooney said:

 

Geez, that pic seems a lot of disassembly for a control column eye.... :p

[Danb]

My thoughts exactly 

[PT20J]

Actually, according to Mooney, it’s made of Nylatron. The gold colored part in the picture is just the alodined stamped-metal housing. If you look carefully you can see the black eyeball inside it.

Mine were easily replaced when we redid the panel, but it would be a bear with everything assembled. 

The hole in the eyeball is larger than the shaft and there is some play. The usual problem that necessitates replacement is that the ball is binding in its socket and they are too tight rather than too loose. This can be a significant source of friction in the elevator controls. The problem is that Mooney used to recommend lubricating them which attracts dust and gums them up and abrades the smooth surfaces. Later Mooney Service Manuals say to leave them dry. Nylatron is supposed to be self-lubricating.

M20Js through 24-0900 used a guide block instead of the eyeballs.

Skip

[Marauder]

9 hours ago, 1980Mooney said:

@Danb Mooney has been using the same "eyeball" or "donut" bearing on the same yoke shaft since 1977 on J through Ultra.  Parts diagram is from an Ovation. (see pic below of Ultra assembly)  I think it is a sintered bronze Oilite sleeve bearing.

Make sure that your yoke shaft is smooth - no imperfections or corrosion. To replace the sleeve bearing you have to remove control handle, disconnect the shaft and carefully remove the wiring on one end.(radio tap to talk switch, pitch controls, etc) in order to get the old bearing off and the new one on.

 

 

19 hours ago, Danb said:

My yoke column seems to have excess play in it. The pilot side has some excess play up and down.

What fix is necessary 

Dan - this is what you should be looking for. This one is on a 79 J.

What I found interesting is that when I did the retrofit of the J style yokes on my F, Mooney sent me a totally different arrangement. Not sure if it was specific for retrofits or there was a period of time when they changed the designed.

[1980Mooney]

1 hour ago, PT20J said:

Actually, according to Mooney, it’s made of Nylatron. The gold colored part in the picture is just the alodined stamped-metal housing. If you look carefully you can see the black eyeball inside it.

Mine were easily replaced when we redid the panel, but it would be a bear with everything assembled. ........

M20Js through 24-0900 used a guide block instead of the eyeballs.

Skip

I replaced my eyeball sleeve bearing while everything was assembled a few years ago for the same reason as mentioned by the OP.  The wires have to be cut, the yoke handle pulled, the wires pulled out of the shaft with a string in place to pull them back in, the linkage disconnected at the firewall and the shaft then pulled towards the firewall to clear it from the instrument panel frame (either out of the bearing or unscrew the bearing cap and pull it all out together).  The yoke shaft (control shaft) has a welded bracket on the firewall side which necessitates pulling it out towards the firewall. (see pic)

Reassembly is the reverse.  It is easiest if your remove the pilot seat.  It is tedious but not difficult.   While under there lubricate all the linkage points and check for play.

[1980Mooney]

57 minutes ago, PT20J said:

Actually, according to Mooney, it’s made of Nylatron. The gold colored part in the picture is just the alodined stamped-metal housing. If you look carefully you can see the black eyeball inside it.

Mine were easily replaced when we redid the panel, but it would be a bear with everything assembled. 

The hole in the eyeball is larger than the shaft and there is some play. The usual problem that necessitates replacement is that the ball is binding in its socket and they are too tight rather than too loose. This can be a significant source of friction in the elevator controls. The problem is that Mooney used to recommend lubricating them which attracts dust and gums them up and abrades the smooth surfaces. Later Mooney Service Manuals say to leave them dry. Nylatron is supposed to be self-lubricating.

M20Js through 24-0900 used a guide block instead of the eyeballs.

Skip

You are correct.  Since 1979 they have used the same bearing on all Mooneys.

I use LP2 which doesn't seem to attract as much dust but I have it in a hangar - might be worse tied down.

[PT20J]

1 hour ago, 1980Mooney said:

I replaced my eyeball sleeve bearing while everything was assembled a few years ago for the same reason as mentioned by the OP.  The wires have to be cut, the yoke handle pulled, the wires pulled out of the shaft with a string in place to pull them back in, the linkage disconnected at the firewall and the shaft then pulled towards the firewall to clear it from the instrument panel frame (either out of the bearing or unscrew the bearing cap and pull it all out together).  The yoke shaft (control shaft) has a welded bracket on the firewall side which necessitates pulling it out towards the firewall. (see pic)

Reassembly is the reverse.  It is easiest if your remove the pilot seat.  It is tedious but not difficult.   While under there lubricate all the linkage points and check for play.

Interesting pic -- I thought all the shafts were chrome plated but this one doesn't appear to be.

[N201MKTurbo]

8 minutes ago, PT20J said:

Interesting pic -- I thought all the shafts were chrome plated but this one doesn't appear to be.

Maybe it was, but the chrome was coming off and it was media blasted and now it isn't. It looks like a used shaft. May not be the one from @1980Mooney's plane.

[1980Mooney]

4 minutes ago, N201MKTurbo said:

Maybe it was, but the chrome was coming off and it was media blasted and now it isn't. It looks like a used shaft. May not be the one from @1980Mooney's plane.

Correct - that is a pic of one salvaged currently for sale.- just to help illustrate because the parts drawings are hard to visualize sometimes.  I thought mine was chrome plated too - however some of it looked a little rough so I polished it as much as I reasonably could.

[N201MKTurbo]

32 minutes ago, 1980Mooney said:

Correct - that is a pic of one salvaged currently for sale.- just to help illustrate because the parts drawings are hard to visualize sometimes.  I thought mine was chrome plated too - however some of it looked a little rough so I polished it as much as I reasonably could.

Yea, mine looks like you describe. half chrome, half warn away chrome. I would get it re-plated if it wasn't such a PITA to take them out.

[Vance Harral]

3 hours ago, Marauder said:

What I found interesting is that when I did the retrofit of the J style yokes on my F, Mooney sent me a totally different arrangement. Not sure if it was specific for retrofits or there was a period of time when they changed the designed.

That black-colored block is exactly what's found in our 1976 M20F, which best as I can tell is factory original.  I think Mooney used this arrangement for a short period of time in the mid-70s, after the older "eyeball" carrier, and before the modern "ring" in your photo of the 1979 J model.

One of our blocks is a bit worn, which leads to some play and chattering in the fore/aft movement of the yoke.  It can be eliminated for a while with a very light coating of TriFlow or other silicone-based lube on the shaft, which I like to think doesn't carry much grit into the block.  But it's probably true that over time, repeated applications of lubricant are just making things worse.  We did purchase a replacement block from LASAR several years ago.  But it turns out to be so much trouble to install it that we've just kept the part on the shelf, until such time as there is other reason for significant disassembly of the yoke and/or shaft mechanisms.

[PT20J]

2 hours ago, Vance Harral said:

That black-colored block is exactly what's found in our 1976 M20F, which best as I can tell is factory original.  I think Mooney used this arrangement for a short period of time in the mid-70s, after the older "eyeball" carrier, and before the modern "ring" in your photo of the 1979 J model.

One of our blocks is a bit worn, which leads to some play and chattering in the fore/aft movement of the yoke.  It can be eliminated for a while with a very light coating of TriFlow or other silicone-based lube on the shaft, which I like to think doesn't carry much grit into the block.  But it's probably true that over time, repeated applications of lubricant are just making things worse.  We did purchase a replacement block from LASAR several years ago.  But it turns out to be so much trouble to install it that we've just kept the part on the shelf, until such time as there is other reason for significant disassembly of the yoke and/or shaft mechanisms.

Yep, that's what I had in my 1978 J. I don't know why Mooney changed; it seemed to work well.

My eyeballs weren't too stiff, but since we were tearing the panel apart it was easy to replace them, and I wanted all the friction out of the elevator controls for the new autopilot. I think the removed parts could be polished smooth but the material is really hard. The new eyeballs and sockets were noticeably smoother, but even they have some breakout force due to the fact that they are machined from solid material and the machining marks are visible in the surface. You can rub your fingernail across the marks and although they aren't deep enough to catch your nail, you can here them "sing."

Skip

[Danb]

6 hours ago, Marauder said:

 

Dan - this is what you should be looking for. This one is on a 79 J.

What I found interesting is that when I did the retrofit of the J style yokes on my F, Mooney sent me a totally different arrangement. Not sure if it was specific for retrofits or there was a period of time when they changed the designed.

Chris I changed the one on the copilot side a few years, what a bear to do, it was binding up. My pilot side is the opposite there is play up and down significantly more the before. Therefore being the opposite set of circumstances led me to inquire about it