Yoke sticky , hanging up

[Guillaume]

Changing the eyeballs (both sides, pilot and copilot) really improved the yoke sliding. 

But now I have to wait for warmer temperature in order to check that the stiffness is totally gone. 

My point was, despite what is written above by other posters, this eyeball should not be lubed. 

Actually lubing this eyeball may damage it but only newer maintenance manuals mention it. 

[FloridaMan]

Verify your control surfaces aren't sticking to gap seals. I've seen anti-chafe tape come loose and the ailerons stick to gap seals. 

[Andy95W]

And check that your new eyeballs aren't too tight.  They should be able to rotate easily in their sockets.  The factory used a bunch of small #6 washers as shims between the metal socket pieces to allow the plastic ball halves to move.

[N201MKTurbo]

So don't think of it as lubing the shafts, think of it as cleaning the shafts with some lubricant that is compatible with the eyeball bearings. They get sticky when they get covered with crud. In all cases they should be wiped as dry as possible after it is done.

It sure makes it easier to fly precisely when they are clean and smooth.

[tmo]

On 1/11/2019 at 1:04 PM, Guillaume said:

I replaced the old eyeballs with new ones (P/N 710070-501, real PIA to do...). 

@Guillaume - I might end up having to do the same; a couple of questions:

 - where did you buy from, how long did you wait? I'm also in the EU, although N-reg.

 - what is the biggest PIA in the replacement? a casual look under the panel makes me think it will be the wiring of the yokes - how does one even disconnect it all? Take the yoke apart, label and remove every wire at switch end?

 - I take it that cleaning them out really well from all the dirt and misplaced lubrication didn't help and they just need to be replaced?

Thanks in advance for any comments, hints or suggestions!

[tmo]

On 1/11/2019 at 5:21 PM, Andy95W said:

And check that your new eyeballs aren't too tight.  They should be able to rotate easily in their sockets.  The factory used a bunch of small #6 washers as shims between the metal socket pieces to allow the plastic ball halves to move.

@Andy95W - just to make sure, you're referring to the "new style" 710070-501 ones, right? Might be something for me to try...

[Guillaume]

1 hour ago, tmo said:

@Guillaume - I might end up having to do the same; a couple of questions:

 - where did you buy from, how long did you wait? I'm also in the EU, although N-reg.

 - what is the biggest PIA in the replacement? a casual look under the panel makes me think it will be the wiring of the yokes - how does one even disconnect it all? Take the yoke apart, label and remove every wire at switch end?

 - I take it that cleaning them out really well from all the dirt and misplaced lubrication didn't help and they just need to be replaced?

Thanks in advance for any comments, hints or suggestions!

- I purchased them from LASAR. Aprox 2 weeks lead time during Christmas 2018 (Mooney had it in stock back then).

- Wiring is the hardest part. There are many cables (yoke lighting, PTT, AP disconnect, CWS, Speedbrakes, possibly trim switch if equipped). Wires were cut behind
 the yoke tube (approx a good meter behind). New wire splices were installed (most of the wires already had a splice anyway).
Disconnecting the wire at switch end is another option but it will require welding inside the aircraft for reinstall. Welding is a precision task and I felt that I might not be able to make a good welding job in the aircraft cockpit. I just wasn't confortable with that.
Carefull cable routing after reinstall is an important task too. You don't want to mess with your flightcontrols.

- When the yokes were off, I wanted to have a new part. I wasn't sure I would be able to clean the old ones back then. 
I installed the new parts right away. Although the old eyeballs were way smoother after cleaning, they were not as smooth as the new ones.

Hope that helps. Good luck !

Edited August 12, 2020 by Guillaume
typo

[tmo]

Just now, Guillaume said:

Wiring is the hardest part.

Makes me wonder if some milspec connector wouldn't be the way to go, instead of cutting and splicing. Then again I guess one takes it all apart this much once every 20 or so years, so maybe it would be a solution looking for an actual problem.

Makes me want to have an intercom install done at the same time...

[Hank]

2 hours ago, tmo said:

@Guillaume - I might end up having to do the same; a couple of questions:

 - where did you buy from, how long did you wait? I'm also in the EU, although N-reg.

 - what is the biggest PIA in the replacement? a casual look under the panel makes me think it will be the wiring of the yokes - how does one even disconnect it all? Take the yoke apart, label and remove every wire at switch end?

 - I take it that cleaning them out really well from all the dirt and misplaced lubrication didn't help and they just need to be replaced?

Thanks in advance for any comments, hints or suggestions!

Digital pictures taken before & during removal can be a great aid during reinstall.

[Guillaume]

6 minutes ago, Hank said:

Digital pictures taken before & during removal can be a great aid during reinstall.

Indeed, it was. 

[PT20J]

Many spray lubricants contain acetone or other carriers that can attack hard plastics. Nylon is fairly fairly resistant, but Delrin is a better choice for a bearing surface. Not sure what Mooney used. So, it’s possible that spray lubes may be the cause of deterioration. Maybe @carusoam has some thoughts. I just lube the shaft itself every so often with with silicone spray and let it dry. 

Skip

[ArtVandelay]

Many spray lubricants contain acetone or other carriers that can attack hard plastics. Nylon is fairly fairly resistant, but Delrin is a better choice for a bearing surface. Not sure what Mooney used. So, it’s possible that spray lubes may be the cause of deterioration. Maybe [mention=7104]carusoam[/mention] has some thoughts. I just lube the shaft itself every so often with with silicone spray and let it dry. 
Skip

Do you know if often recommended Triflow is safe for Delrin?

[Andy95W]

8 hours ago, tmo said:

@Andy95W - just to make sure, you're referring to the "new style" 710070-501 ones, right? Might be something for me to try...

@tmo- no, I was talking about the really old ones.  

But IIRC the concept is the same, the eyeball/guideblock should be able to move a little to allow the yoke shaft to pivot slightly up and down as the shaft slides in and out.

[Guillaume]

1 hour ago, ArtVandelay said:

Do you know if often recommended Triflow is safe for Delrin?

The new maintenance manuals are quite clear regarding 710070-501 lubrication.

Unfortunately for me, this piece of information is still not in the latest M20J Maintenance manual (although aircraft are equipped with it). 

Mooney doesn't care.

[PT20J]

1 hour ago, ArtVandelay said:

Do you know if often recommended Triflow is safe for Delrin?

No, I don't know. I'm not even sure what plastic material Mooney used. My point was simply that the later recommendation to keep it dry might be to protect the material from some ingredients in spray lubricants. But that's just speculation.

[carusoam]

Sorry I’m late...    (Mom said I’m going to be late to my own funeral.... I’m still putting that one off as long as possible...)

Delrin is the special polymer of choice for precision molded parts...

The key application it got famous for was the cassette tape reals... any loss of precision would cause sound variations related to rpm of the drive system....

Do you remember... the tape getting stuck and the cassette being ejected and the streamer that resulted....?

 

From DuPont the manufacturer...

The Acetal polymer has some allergies with certain solvents...

There is a list of environmental things to avoid in this design related brochure... looks like they simplified it down to check marks and do not enter signs... 

https://dupont.materialdatacenter.com/en/products/datasheet/SI/Delrin® 100 BK602

Nylons... the  polymer moth the article of clothing... easy to react from the liquid caprolactam... with a diisocynate used to initiate the chemical reaction... the end result is a plastic part in the shape of the mold you put it in... it gets sent of to heated oil bath for stress relief in a process step called annealing... overnight in an oil bath... it has high impact strength, resists oils pretty well... and can be machined, after it has been Annealed....

Putting nylon parts on the band saw before they get annealed... is sure to annoy the say owner....   

Now...

Regarding a spray can of triflow... have to find the MSDS for that... that is going to be an interesting solvent to be  able to dissolve some form of Teflon in it....

Teflon was a DuPont discovery as well... they found it in a compressed cylinder of some hydrofluoric gas.... the cylinder weighed like it was full, but had no pressure in it...   literally a discovery... not an invention...

Go DuPont!

If you take a look at section three of this MSDS for Tri-flow... it details the list of solvents used to dissolve Teflon...

Heck, if it can dissolve Teflon.... I don’t think I would want to use it near anything polymeric.... without testing it first...

section three fell of the graphic image here.... so follow the link to see the rest...

http://www1.mscdirect.com/MSDS/MSDS00010/00157545-20161002.PDF

Great for lubricating aluminum or steal parts...

PP thoughts only, not the scientist I pretend to be on MS... 

Thanks for letting me play along... please ask me questions if I missed something...

Best regards,

-a-

[tmo]

Would the liquid TRI-FLOW (squeeze bottle) be any better than the spray? Guess not, or not much, since it still has to have the teflon dissolved.

[tmo]

For future reference, the August 2020 price for the 710070-501 eyeball assembly is $135 and they are available from Mooney via LASAR.

Dan from LASAR also suggested I try to polish the yoke shaft with the finest steel wool and WD40 (another acceptable aviation application - ha!) and see if that helps.

Like Guillaume, I just ordered the parts - if the WD40 helps for the time being, I'll have spares in stock.

Edited to report that the WD40 and the 0000 steel wool therapy for the yoke shaft did wonders - no more binding.

Edited August 22, 2020 by tmo

[ArtVandelay]

For future reference, the August 2020 price for the 710070-501 eyeball assembly is $135 and they are available from Mooney via LASAR.

Dan from LASAR also suggested I try to polish the yoke shaft with the finest steel wool and WD40 (another acceptable aviation application - ha!) and see if that helps.

Like Guillaume, I just ordered the parts - if the WD40 helps for the time being, I'll have spares in stock.

Is Mooney factory open for business again? As of about a week ago, they said no.

 

 

Tom

[PT20J]

1 hour ago, ArtVandelay said:

Is Mooney factory open for business again? As of about a week ago, they said no.

 

 

Tom

Not sure what you mean by "open for business" or who "they" is.

Last month, Stacey Ellis was answering emails and they were filling parts orders from stock for LASAR.

Skip

[ArtVandelay]

Not sure what you mean by "open for business" or who "they" is.
Last month, Stacey Ellis was answering emails and they were filling parts orders from stock for LASAR.
Skip

10 days ago LASAR told me to call back next month, Mooney wasn’t filling orders. So if they don’t have it in stock then you’ll need to wait.

[tmo]

The exact wording of the email was:

> I checked stock with Mooney and they have both parts in stock. I can get them ordered ...

I take it to mean Mooney has the part in stock AND there is someone at Mooney who can ship it to LASAR.

[carusoam]

TMO,

The solvent that is strong enough to dissolve TFE... won’t matter if it is delivered via pentane or any other blowing agent...

WD40 makes a nice solvent for cleaning stuff off of metal parts... and pretty safe for plastic parts too...

I always want to make sure that paint and acrylic won’t be affected by solvents used on them...

Best regards,

-a-

[N231BN]

In addition to the yoke shafts sticking I also had an issue with the counterweight rubbing on the firewall blanket, one other thing to check.

[PT20J]

According to Kevin Kammer at the factory, the eyeballs are made of Nylatron. I checked the chemical compatibility and it is impervious to most solvents. Kevin says they are supposed to be self lubricating, but he didn't see why Tri-flow couldn't be used.

I've been trying to chase down a little "shudder" in my trim mechanism ever since I bought the airplane a 2-1/2 years ago. It only happens when trimming nose down manually on the ground. I cannot notice it in the air. I finally figured out that the cause was some minor friction in these ball joints. I took them loose from their mounting (but did not take them off the shaft which is a major operation) and cleaned them off. I noticed that the ball feels a little rough in it's motion in the race. I lubed it with some silicone plumber's grease which seemed to help. I also ordered a couple of new ones in case I decide to replace them. I received them today and noticed that the new ones, although smoother, still have a noticeable breakout force if loaded. There are very fine machining marks on the ball and race that increase the friction. You can only see them with magnification, but you can hear them singing if you work the two parts together or run your fingernail across the surface. Polishing the old ones smooth is probably just as good -- perhaps better -- than replacing them.

Skip