Flail Mower JD 25a Driveside Bearing Removal

[frankydp]

Morning folks,

Just acquired a JD 25A of the 644700 series of serials for a couple hundred dollars. Unit was missing some blades and appeared to have all of the original duck feet, so I replaced all missing and old knives with some side slicers from FM. After getting all of those installed, the unit was still vibrating more than I wanted, so I looked a little more and discovered that the rotor bearing on on the drive side was mostly disintegrated.

I can not get the locking collar to budge. The operating manual implies that it has some kind of twist lock function when installing, is that really the case when the locking screw is out? Do I need to remove the entire bearing housing/support? The diagram on jd parts leaves some stuff to interpretation, with some call out boxes that are not arrowed in, and probably refer to a production change.

Anyways, any help would be appreciated, and any gotchas that anyone knows about would be great.

 

[leonz]

Morning folks,

Just acquired a JD 25A of the 644700 series of serials for a couple hundred dollars. Unit was missing some blades and appeared to have all of the original duck feet, so I replaced all missing and old knives with some side slicers from FM. After getting all of those installed, the unit was still vibrating more than I wanted, so I looked a little more and discovered that the rotor bearing on on the drive side was mostly disintegrated.

I can not get the locking collar to budge. The operating manual implies that it has some kind of twist lock function when installing, is that really the case when the locking screw is out? Do I need to remove the entire bearing housing/support? The diagram on jd parts leaves some stuff to interpretation, with some call out boxes that are not arrowed in, and probably refer to a production change.

Anyways, any help would be appreciated, and any gotchas that anyone knows about would be great.


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Hello frankiedp,

I want to welcome you as the newest member of the Flail Mower Nations from the Great State of Georgia,

Please do not get upset with me, but I strongly suggest you replace the opposite bearing as well.

Remove the set scew and set it somewhere so it does not get lost, spray in some PB blaster several times to let it soak overnight, then wearing gloves wrap the stub shaft in an old towel filled with broken dry ice Please do not break up the dry ice without wearing eye protection and making sure its wrapped in the old towel when breaking it up.
Then using some duct tape to hold the dry ice wrapped in the old towel all on around the stub shaft so you can shrink the stub shaft and the locking collar should pop right off.

If you have a pry bar with a curved foot that will help remove the locking collar after you remove the towel filled with dry ice.


The upper left exploded diagram is what you have with that 25A so you need to remove the cover plate to change the bearing. as long as you have the Flail Mowers Rotor supported with wooden blocking you can do it with few issues by unbolting the the bearing flange bolts then the outer plate mounting bolts after you have pulled off the locking collar.

Please make doubly sure you have a good tarp under that side of the mower to catch any parts that drop and be sure to replace all the nuts and nylock bolts with new ones or new fine thread nuts and bolts using blue loctite to secure the fine threaded nuts.


You have a forever mower there franky, happy mowing.

 

[Member]

I have a 25A too and I have done this. I wish I could remember the exact process but I don’t. What I do remember is that removing the eccentric locking collar took a lot less force than I thought it would when I finally figured it out. I did not use penetrating oil or dry ice. I think I did remove the bearing support because I had to so the other side woild come out? Anyway, I would Google for “removing bearing eccentric locking collar”. Sorry if this isn’t very helpful.

 

[frankydp]

Alright. Just adding these here for posterity/google/forum search.

When removing the rotor bearing locking collar on a John Deere 25A, the locking collar is an eccentric type. This means that the collar threads onto the bearing itself. You will need to rotate the collar approximately 1-1/2 full turn. I found it easiest to back out the locking nut a little bit and then attach a large pipe wrench, since I will be replacing the collar. I then slid the flywheel back on and turned them opposite. See image below. Once it is unlocked from the bearing thread it should slide off pretty easily, gentle hammer claw easy.

Second picture is just of the thread on the bearing just so you can visualize.

Thanks @Member that google search put me on the right path. Next step of removing the support ring and bearing looks to be much more difficult, will probably ice it and then pull.

NAP Eccentric Collar Lock - YouTube Video of a locking collar.

 

[Thorride138]

Morning folks,

Just acquired a JD 25A of the 644700 series of serials for a couple hundred dollars. Unit was missing some blades and appeared to have all of the original duck feet, so I replaced all missing and old knives with some side slicers from FM. After getting all of those installed, the unit was still vibrating more than I wanted, so I looked a little more and discovered that the rotor bearing on on the drive side was mostly disintegrated.

I can not get the locking collar to budge. The operating manual implies that it has some kind of twist lock function when installing, is that really the case when the locking screw is out? Do I need to remove the entire bearing housing/support? The diagram on jd parts leaves some stuff to interpretation, with some call out boxes that are not arrowed in, and probably refer to a production change.

Anyways, any help would be appreciated, and any gotchas that anyone knows about would be great.


View attachment 522654View attachment 522655View attachment 522656View attachment 522657

===========================================================================================

Hello frankiedp,

I want to welcome you as the newest member of the Flail Mower Nations from the Great State of Georgia,

Please do not get upset with me, but I strongly suggest you replace the opposite bearing as well.

Remove the set scew and set it somewhere so it does not get lost, spray in some PB blaster several times to let it soak overnight, then wearing gloves wrap the stub shaft in an old towel filled with broken dry ice Please do not break up the dry ice without wearing eye protection and making sure its wrapped in the old towel when breaking it up.
Then using some duct tape to hold the dry ice wrapped in the old towel all on around the stub shaft so you can shrink the stub shaft and the locking collar should pop right off.

If you have a pry bar with a curved foot that will help remove the locking collar after you remove the towel filled with dry ice.


The upper left exploded diagram is what you have with that 25A so you need to remove the cover plate to change the bearing. as long as you have the Flail Mowers Rotor supported with wooden blocking you can do it with few issues by unbolting the the bearing flange bolts then the outer plate mounting bolts after you have pulled off the locking collar.

Please make doubly sure you have a good tarp under that side of the mower to catch any parts that drop and be sure to replace all the nuts and nylock bolts with new ones or new fine thread nuts and bolts using blue loctite to secure the fine threaded nuts.


You have a forever mower there franky, happy mowing.

How do you press the new bearings back into the housings?

 

[wirlybird]

Good info here. Thanks.
If anyone comes across spare upper and lower pulleys, I'm looking for replacements for my 25A.