77’ J gear trouble

[N201MKTurbo]

1 hour ago, ArtVandelay said:

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

I think it all started with the 20:1 gears. They wore out pretty fast. When they changed to the 40:1 gears they required the inspections because they didn’t know how long they would last. They seem to last a long time. If someone wanted to go to the trouble, they could probably get the inspection interval extended. 
 

When I look at the two actuators, I see the Dukes as a highly engineered aerospace component that was designed to be as light as possible and still meet the requirements. When I look at the Eaton actuator, I see a heavy assembly that was quickly designed with little regard to weight.

[MikeOH]

13 hours ago, N201MKTurbo said:

Reinstall the gear and do the prescribed inspection with the gauge wire….

I usually disassemble the right angle bevel gear box too,

I also degrease and re-lube the jack screw while it is off.

Is the gauge wire described in the AD; I only recall a backlash spec?

Do you use the same moly grease for the right angle and jack screws, or?

[N201MKTurbo]

3 hours ago, MikeOH said:

Is the gauge wire described in the AD; I only recall a backlash spec?

Do you use the same moly grease for the right angle and jack screws, or?

Now you have me wondering where I saw that. It may be in the service manual. It mentioned using a 0.020 lock wire and if you can slide it between the gear teeth it was beyond limits.

Anyway, here is the inspection from the AD. It specifically says you have to remove the actuator. And, yes I use the same grease.

 

Well, that didn't format very well....

 

TIME OF Part I: Within next 25 hours of operation and every 200 hours thereafter. COMPLIANCE: Part II: Every 100 hours. Part III: Within next 25 hours in conjunction with Part I INTRODUCTION: In order to check gear teeth wear, assure proper lubrication and prevent Heim bearing seizure, comply with Instructions below. Access to the actuator is gained by removal of the fuselage belly plate, P/N 310124. In lubricating the actuator gear housing use only Dukes Astronautics Co.; special purpose grease P/N 2196-74-1, Aeroshell Grease # 7, or MIL-PRF-23827 (with a minimum of 10% (by vol.) Molybdenum Disulfide added to any of the grease used).

INSTRUCTIONS: PART I: 1. Place the aircraft on jacks. 2. Remove the actuator from the aircraft. 3. Remove the six end cap bolts and flush actuator thoroughly with solvent. Air dry. 4. Visually inspect gears for wear as illustrated in Figure 1. 5. With open end of actuator toward you, rotate jack screw shaft counter clockwise to remove all slack from ring and worm gears. Make an index mark on one gear tooth and on the inside of housing. Turn jack screw shaft clockwise until ring gear contacts worm gear and check index marks. 6. Visible wear or backlash of ½ tooth or more requires immediate replacement of gears. S.B. Kit M20- 190-1 contains necessary gears. 7. If replacement of gears is necessary be sure when installing to re-secure the nut by applying Loctite #242 to the back side and restake with a center punch. The worm gear cap must also be staked to lock it in place. 8. Before installing end cap, fill gear housing with lubricant specified in Introduction. 9. Install end cap making sure the two shorter bolts are installed on the worm gear side of the housing. Safety wire the bolts in pairs. 10. Reinstall actuator into aircraft following instruction in PART III. Check preload per Mooney Service & Maintenance Manual and Service Instruction M20-32.

[Grant_Waite]

So I called Maxwell and the A&P, the previous owner used. They both said the identical thing. They don’t think it’s the motor because no circuit breaker is popping and the motor continues to run when the gear stops retracting. They said it’s possibly the rubber coupling that goes between the motor and transmission or the shock disc are too worn. The shock disc are 12 years old, so they could be an issue. I planned to replace this annual. Maxwell said that the dukes is a good motor and mine has had good maintenance. He also said they are in R&R of a solution to fix all this mess. That’s all the detail he’d give me on that. I’d rather pay 5k to remove, clean, paint, and put new hardware on the gear trusses than pay 11k for a new motor. Idk why but having the gear trusses look like crap really takes away from it looking nice. 

[EricJ]

1 hour ago, N201MKTurbo said:

Now you have me wondering where I saw that. It may be in the service manual. It mentioned using a 0.020 lock wire and if you can slide it between the gear teeth it was beyond limits.

Anyway, here is the inspection from the AD. It specifically says you have to remove the actuator. And, yes I use the same grease.

The AD applies to Dukes PN 4196-00-1C.   The OP has the same actuator as I do, PN 1057-00-5, which is not subject to the AD.   Lubrication is certainly a good idea, and probably occasional inspection, but it isn't required.

[Ragsf15e]

1 hour ago, Grant_Waite said:

So I called Maxwell and the A&P, the previous owner used. They both said the identical thing. They don’t think it’s the motor because no circuit breaker is popping and the motor continues to run when the gear stops retracting. They said it’s possibly the rubber coupling that goes between the motor and transmission or the shock disc are too worn. The shock disc are 12 years old, so they could be an issue. I planned to replace this annual. Maxwell said that the dukes is a good motor and mine has had good maintenance. He also said they are in R&R of a solution to fix all this mess. That’s all the detail he’d give me on that. I’d rather pay 5k to remove, clean, paint, and put new hardware on the gear trusses than pay 11k for a new motor. Idk why but having the gear trusses look like crap really takes away from it looking nice. 

12 yo shock discs on an F are practically new…

[Grant_Waite]

57 minutes ago, EricJ said:

The AD applies to Dukes PN 4196-00-1C.   The OP has the same actuator as I do, PN 1057-00-5, which is not subject to the AD.   Lubrication is certainly a good idea, and probably occasional inspection, but it isn't required.

This is correct information, our part numbers don’t match the ones in the AD. So does this mean our motors don’t suffer from the same gear tooth wear as described? 

[N201MKTurbo]

From the service manual:

[EricJ]

39 minutes ago, Grant_Waite said:

This is correct information, our part numbers don’t match the ones in the AD. So does this mean our motors don’t suffer from the same gear tooth wear as described? 

It's tough to find data, and the frequency of gears failing seems to be very low regardless of actuator specifics.    That said, it's not a bad idea to inspect it once in a while, and it's definitely a good idea to keep it lubed properly.

[Grant_Waite]

On 6/24/2024 at 7:48 PM, EricJ said:

It's tough to find data, and the frequency of gears failing seems to be very low regardless of actuator specifics.    That said, it's not a bad idea to inspect it once in a while, and it's definitely a good idea to keep it lubed properly.

Flew my plane to the mechanics yesterday, apparently the cable connecting the emergency gear crank to the back of the motor is destroyed. He said the gear must have actuated with it engaged. Not sure how the hell it happened. Could be vibration, my leg hit it just a little, not sure. It was doing it before the heat swing so I didn’t do it then. Just a fluke thing I suppose. So I’m going to see if McFarlane can make me a new emergency gear extension cable, since Dan at Lasar said they don’t exist new. Someone on here said they had one made by them in 21. I’m going to the motor to Lasar and have the 200hr ad done and look to see if anything got damaged. If it did, I’ll weigh the cost to fix it and if the parts are even available. If they aren’t I’m going to have Lasar build me an Eaton motor core than will work with my older style crank extension. That’s what the guy Lasar said he does. 

[jetdriven]

I have all the Dukes hardware that came out of our 77J including that cable. If you’re going to convert to the Eaton unit, go ahead and go all the way and get rid of that side crank and put the floor pulll handle in the airplane and then you can free up some space in the left side for a pocket,

[EricJ]

17 minutes ago, Grant_Waite said:

Flew my plane to the mechanics yesterday, apparently the cable connecting the emergency gear crank to the back of the motor is destroyed. He said the gear must have actuated with it engaged. Not sure how the hell it happened. Could be vibration, my leg hit it just a little, not sure. It was doing it before the heat swing so I didn’t do it then. Just a fluke thing I suppose. So I’m going to see if McFarlane can make me a new emergency gear extension cable, since Dan at Lasar said they don’t exist new. Someone on here said they had one made by them in 21. I’m going to the motor to Lasar and have the 200hr ad done and look to see if anything got damaged. If it did, I’ll weigh the cost to fix it and if the parts are even available. If they aren’t I’m going to have Lasar build me an Eaton motor core than will work with my older style crank extension. That’s what the guy Lasar said he does. 

Check the spring and the Bowden cable and the mechanism that disconnects the emergency actuator cable at the actuator.   If that got hung up, or dirty, or sticky, or something, it could leave the cable partially engaged when the motor comes on.   

If you can't get an emergency actuator cable easily, @N201MKTurbo fairly recently found all the materials to make a replacement and may have some input.   

[Grant_Waite]

2 hours ago, EricJ said:

Check the spring and the Bowden cable and the mechanism that disconnects the emergency actuator cable at the actuator.   If that got hung up, or dirty, or sticky, or something, it could leave the cable partially engaged when the motor comes on.   

If you can't get an emergency actuator cable easily, @N201MKTurbo fairly recently found all the materials to make a replacement and may have some input.   

The plane is not anywhere close to me, so I can’t go easily look at it. Hopefully the motor didn’t get all messed up but who knows. I’m sure this has happened to others before but I find it odd that it does happen. I guess nothing is fool proof. Hopefully Mcfarlane can make a new one. The one post stated it only cost 225 in 21 which isn’t bad.