77’ J gear trouble

[Grant_Waite]

My gear motor is having issues in my 1977 M20J. It’s the Dukes 1057-00-5. I just got done greasing it using the aeroshell#7 with 10% molybdenum mix. It was having issues before I greased it. I did the grease while the panels were off. It won’t retract the gear all the way. It doesn’t happen every time either. Most times it doesn’t, but sometimes it does. I tried using the emergency gear extension and it would stop moving the gear about 75 plus cranks into it. I read that if the motor gears are bad, the emergency gear extension won’t work either, because it uses the gears in the motor to crank the gear down. Glad I didn’t find that one out in an actual emergency! The gear has never had an issue coming down luckily. I’m looking at replacing the whole motor and getting rid of the emergency gear crank, in favor of the later model Eaton motors. Lasar seems to be the only place that has yellow tagged ones listed. I need to call Monday to see if they have any available. The gear motor had a new jackscrew assembly installed in 23 by don maxwell. If anyone could give me insight on if the Eaton retrofit is possible and if which of these motors from Lasar are the correct one. I have a video of the gear but it won’t let me upload from my phone. I need to call Lasar and Maxwell on Monday.  https://lasar.com/actuators

[jetdriven]

We just did that and we retrofitted a newer style Avionics products (Eaton) actuator.  You’ve got to convert the plane and it takes some extra stuff to do that. We also have the Dukes actuator that came from our plane and an Eaton actuator here.  

[N201MKTurbo]

What happens when you try to raise the gear? Do you hear the motor running and the gear isn’t coming up? Does it pop the breaker? Is the gear unsafe light still on? 
 

You said you tried the emergency extension. I hope you were not using it to retract the gear. That can ruin the cable. 
 

Have you watched the actuator while it is retracting? Does the rubber coupling keep spinning after the gear stops moving? Can you finish retracting it by spinning the rubber coupling with your fingers?

[EricJ]

^^This.    I'd make sure it's actually the gear actuator causing the problem before changing it out.   With the airplane on jacks you can learn a lot, and can disconnect the actuator and move the gear by hand to see if something is binding somewhere.    There are a lot of things that can be wrong beside the gears. 

[Fritz1]

as stated before, check everything out on jacks with belly pan off, may not even be the actuator, however the dukes actuator is known to be undersized for the job and may just give you warning before it really fails, I replaced the Dukes with an Eaton in my 68 G model 25 years ago since the motor was burned out, dragged through New York traffic with gear hanging out and burnt smell in the cockpit, think there was a Mooney kit for the replacement, Maxwell, LASAR and our jetdriven know all the pros and cons and ins and outs

[Grant_Waite]

4 hours ago, N201MKTurbo said:

What happens when you try to raise the gear? Do you hear the motor running and the gear isn’t coming up? Does it pop the breaker? Is the gear unsafe light still on? 
 

You said you tried the emergency extension. I hope you were not using it to retract the gear. That can ruin the cable. 
 

Have you watched the actuator while it is retracting? Does the rubber coupling keep spinning after the gear stops moving? Can you finish retracting it by spinning the rubber coupling with your fingers?

The gear will start to come up and then it stops. The motor still runs but sounds like it’s binding. The jackscrew will move and then it stops almost like it’s not getting enough power. No, the circuit breakers don’t pop but the gear unsafe light stays on until I select gear down. No, I didn’t raise the gear with the emergency extension. I know it’s only for down operation. The emergency extension had issues about 75 plus cranks into it. I would like to ditch the dukes motor if I can, even if it’s not per se the culprit. I know this motor will have more issues and I don’t want to play around with gear issues. 

[EricJ]

44 minutes ago, Grant_Waite said:

The gear will start to come up and then it stops. The motor still runs but sounds like it’s binding. The jackscrew will move and then it stops almost like it’s not getting enough power. No, the circuit breakers don’t pop but the gear unsafe light stays on until I select gear down. No, I didn’t raise the gear with the emergency extension. I know it’s only for down operation. The emergency extension had issues about 75 plus cranks into it. I would like to ditch the dukes motor if I can, even if it’s not per se the culprit. I know this motor will have more issues and I don’t want to play around with gear issues. 

How fast are you going when this happens?   The faster you are the harder it is for the gear to come up.   I've found on my airplane I need to have the gear up before about 90 knots or it'll have trouble.

The actuator can be disassembled and checked.   There haven't really been that many examples of failures of the gears, and the motor is serviceable if it is a motor issue.

 

[Grant_Waite]

1 hour ago, EricJ said:

How fast are you going when this happens?   The faster you are the harder it is for the gear to come up.   I've found on my airplane I need to have the gear up before about 90 knots or it'll have trouble.

The actuator can be disassembled and checked.   There haven't really been that many examples of failures of the gears, and the motor is serviceable if it is a motor issue.

 

Not fast at all, I pull my gear up as soon as I get off the ground. I’d say I’m well below 90. 

[BlueSky247]

So just curious - if someone is shopping for a J, how do you ensure this won't be a problem? Make sure the motor and actuators are on the inspection list? Check the logs for updated parts?

[PT20J]

During prepurchase the airplane will be opened up. Witness or have the inspector take pictures of the actuator including the ID plates. Examine the logbooks for what's been done to the actuator: Dukes: 40:1 gear installed? Periodic lubrication, AD compliance?; Eaton: noback spring replacement; Plessey, well, I wouldn't buy it with a Plessey personally.

[PT20J]

3 hours ago, Grant_Waite said:

The gear will start to come up and then it stops. The motor still runs but sounds like it’s binding. The jackscrew will move and then it stops almost like it’s not getting enough power.

Sounds like you did this with the airplane on jacks and the belly opened so that you could watch the jackscrew. If the jackscrew stops, of course the gear will stop retracting. There is not, to my knowledge, a slip clutch in the actuator, and the fact that there is also a problem with cranking the gear down manually leads me to think that something is stripped, especially if the gear stops moving but the motor keeps turning. If it's happening at the same point retracting with the actuator and extending with the crank, I might look closely at the jack screw for a damaged spot.

[Grant_Waite]

2 hours ago, PT20J said:

Sounds like you did this with the airplane on jacks and the belly opened so that you could watch the jackscrew. If the jackscrew stops, of course the gear will stop retracting. There is not, to my knowledge, a slip clutch in the actuator, and the fact that there is also a problem with cranking the gear down manually leads me to think that something is stripped, especially if the gear stops moving but the motor keeps turning. If it's happening at the same point retracting with the actuator and extending with the crank, I might look closely at the jack screw for a damaged spot.

It was indeed done on jacks with the panels off. So the speed was not something that could be causing it. The jackscrew was the last thing replaced on the motor in 2023 by the previous owner. It has definitely flown past the 200hr inspection but I have greased it twice now. It just seems like this motor is a very troublesome. I plan on flying it to the mechanic that the previous owner used with the gear down. He has all the tools and has rigged the gear before. So it’ll probably be 2hr or so flight with the gear down. 

[1980Mooney]

5 minutes ago, Grant_Waite said:

It was indeed done on jacks with the panels off. So the speed was not something that could be causing it. The jackscrew was the last thing replaced on the motor in 2023 by the previous owner. It has definitely flown past the 200hr inspection but I have greased it twice now. It just seems like this motor is a very troublesome. I plan on flying it to the mechanic that the previous owner used with the gear down. He has all the tools and has rigged the gear before. So it’ll probably be 2hr or so flight with the gear down. 

You probably saw this in the Safety & Accident Forum.  It is a 1974 M20F with electric gear.  It probably has the same Dukes actuator as your plane.  They were also flying with the gear down to get to a mechanic who could fix it.

 

[Ron McBride]

Please read the ad, if I remember correctly there is a 200 hour inspection on the gears.

 

[EricJ]

It's possible it could be something as simple as the brushes in the motor, which can be serviced, or a frayed wire or bad contact or even a bad contact in one of the relays.

   

[N201MKTurbo]

The Dukes actuator is perfectly adequate for the job. If it is properly maintained, it will give decades of reliable service.
 

If maintenance is skipped or not adequately done, well, you get what you pay for. I wouldn’t throw it out, because of some bad turnout for some improperly maintained actuators.  

[1980Mooney]

4 hours ago, PT20J said:

During prepurchase the airplane will be opened up. Witness or have the inspector take pictures of the actuator including the ID plates. Examine the logbooks for what's been done to the actuator: Dukes: 40:1 gear installed? Periodic lubrication, AD compliance?; Eaton: noback spring replacement; Plessey, well, I wouldn't buy it with a Plessey personally.

 

4 hours ago, BlueSky247 said:

So just curious - if someone is shopping for a J, how do you ensure this won't be a problem? Make sure the motor and actuators are on the inspection list? Check the logs for updated parts?

Do you understand why Skip @PT20J advised to avoid a Plessey actuator?

• Plessey is no longer supported and the "no back spring" for the Plessey actuator is not available
• If you have a Plessey fail, the only option is to replace it with an Eaton
  • The last prices that I saw for a yellow tagged used Eaton actuator that has been repaired by Lasar was about $11,000 (and that is just the unit - shipping, tax, installation,... more)
• I would budget about $15,000 when it is all said and done
• If you fall in love with a plane with a Plessey - ask for a $15,000 price reduction.

When you look at M20J's you will find

• Duke's actuators  - installed on M20J in 1977 through serial no. 24-0377
• ITT actuators (that are basically copies of Duke's) that may have replaced a Dukes
• Eaton style actuators with the names Avionics Products Company, CONDEC, Vickers or Eaton (all the same design and built in the same place - company just sold many times ultimately to Eaton)
• Plessey or (GEC) Plessey - installed starting in the early 90's

Edited June 24 by 1980Mooney

[Grant_Waite]

1 hour ago, 1980Mooney said:

You probably saw this in the Safety & Accident Forum.  It is a 1974 M20F with electric gear.  It probably has the same Dukes actuator as your plane.  They were also flying with the gear down to get to a mechanic who could fix it.

 

Sounds like they had a different issue than mine. I don’t have any circuit breaker popping or any issue with it being down and locked. I don’t. See how they could have taxied and took off if the one gear wasn’t locked. The planes are way too bouncy for something to not collapse. Considering the plane was taxied back after the gear swings, I feel it’s down and locked. My issue isn’t the gear down part, luckily. I don’t have anyone on field to do this work so, I’m sol. 

[Grant_Waite]

1 hour ago, N201MKTurbo said:

The Dukes actuator is perfectly adequate for the job. If it is properly maintained, it will give decades of reliable service.
 

If maintenance is skipped or not adequately done, well, you get what you pay for. I wouldn’t throw it out, because of some bad turnout for some improperly maintained actuators.  

The fact that it has to be removed every 200 hours is a huge turn off and pia for me. I’ve flown almost 200 hours in less than 6months but the cost of the Eatons are high. So I’m not sure what I’ll do. I’m definitely not throwing out the old motor. I would probably end up sending it to Lasar if I do go the Eaton route. 

[N201MKTurbo]

Just now, Grant_Waite said:

The fact that it has to be removed every 200 hours is a huge turn off and pia for me. I’ve flown almost 200 hours in less than 6months but the cost of the Eatons are high. So I’m not sure what I’ll do. I’m definitely not throwing out the old motor. I would probably end up sending it to Lasar if I do go the Eaton route. 

Removing the actuator is pretty easy. The hardest part is the emergency extension disconnect cable. I have a one piece belly, so getting access isn’t that hard. If you are flying 200 hours a year, good for you. I used to do that, but not in a plane with an actuator. There is a 100 hour requirement for lubrication, once opened up for lubrication, the actuator inspection should only add an hour or so to the process. It isn’t that hard to do.

[Grant_Waite]

26 minutes ago, N201MKTurbo said:

Removing the actuator is pretty easy. The hardest part is the emergency extension disconnect cable. I have a one piece belly, so getting access isn’t that hard. If you are flying 200 hours a year, good for you. I used to do that, but not in a plane with an actuator. There is a 100 hour requirement for lubrication, once opened up for lubrication, the actuator inspection should only add an hour or so to the process. It isn’t that hard to do.

Yeah, I wish I had the one piece belly. Right now I have the first 2 panels off. It seems that I would need the red latch, and trim for the Eaton emergency extension if I go that route. Not sure if either of those things are available to get. I want the meat down time possible but also don’t want to cheap out on anything either. I know how important the gear is so I don’t want to mess around. It’s great building all this retractable time but it comes at a cost. 

[EricJ]

49 minutes ago, Grant_Waite said:

The fact that it has to be removed every 200 hours is a huge turn off and pia for me. I’ve flown almost 200 hours in less than 6months but the cost of the Eatons are high. So I’m not sure what I’ll do. I’m definitely not throwing out the old motor. I would probably end up sending it to Lasar if I do go the Eaton route. 

There is no actual requirement for actuator removal for maintenance on your airplane, and the lubrication is easy to do and isn't time consuming even considering removing the panels.   There are advantages to the crank-style gear extension, including that it can't be kicked into partial engagement by rear seat passengers (like the later pull-style extension system).   You don't have to remove the actuator to lubricate it.   I've owned mine for seven years and about 850 hours and it's never been out since I've had it, and there's no evidence that it was ever taken out previously that I've seen.

As mentioned previously, the gears haven't shown to be a big deal for failures, nor have the no-back springs, which would be the (similarly-non) issue with the later actuators.   

 

[N201MKTurbo]

12 minutes ago, Grant_Waite said:

Yeah, I wish I had the one piece belly. Right now I have the first 2 panels off. It seems that I would need the red latch, and trim for the Eaton emergency extension if I go that route. Not sure if either of those things are available to get. I want the meat down time possible but also don’t want to cheap out on anything either. I know how important the gear is so I don’t want to mess around. It’s great building all this retractable time but it comes at a cost. 

I suspect that there a lot of shops that don’t want to take responsibility for disassembling and inspecting the actuator. Even though it takes less time than packing it for shipping. It is not a complicated assembly. 
 

 

[N201MKTurbo]

When I do the inspection. I remove the actuator, pull the worm ring gearbox off the actuator (four bolts), pull the cap off the gearbox, remove the ring gear. Completely degrease the assembly. Inspect the ring gear with a magnifying glass. Reinstall the gear and do the prescribed inspection with the gauge wire. Even though I know if it will pass before I do the official inspection, then pack as much new grease as I can with my finger. Then reinstall the cover. Then grease it with the grease gun, just to make sure it is full. I usually disassemble the right angle bevel gear box too, even though it isn’t required. It doesn’t take very long. When I’m done I have a high confidence that it is good to go. I also degrease and re-lube the jack screw while it is off. The whole process takes about an hour. It takes about another 1/2 hour to R&R it.

[ArtVandelay]

The Dukes actuator is perfectly adequate for the job. If it is properly maintained, it will give decades of reliable service.
 
If maintenance is skipped or not adequately done, well, you get what you pay for. I wouldn’t throw it out, because of some bad turnout for some improperly maintained actuators.  

Why does the Dukes actuator require this much maintenance, where the Eaton doesn’t? Is the Eaton just sealed better or have stronger components?