RC48 mower deck removal question

[Roger Fowler]

I just removed the mower deck from my G1800. The yoke for the driveshaft is still attached to the front PTO shaft. How do I remove it? I would hate to have someone engage the PTO and have it flail around hitting stuff. Thanks in advance.

Roger

 

[Hugo Habicht]

Hi Roger,

there is a locking mechanism in the front piece. You have to pull the ring (red arrow) back towards the u-joint to open it and then pull off the whole thing off the PTO shaft.

Kind regards,
Hugo

 

[Tractor Gal]

If your mower is like other Kubota mowers, there is a "button" that must be depressed that will release the shaft from the splines. As shown above, you can see the "button."

It's a job, by the way! Very little space to move...and the grease makes it slippery!

TG

 

[Hugo Habicht]

The only PTO shafts for mower decks of those tractors I have seen (not many, I admit freely ) had this ring mechanism.

There are three steel balls inside that are locked by the ring.

This is when the ring is forward.

When you pull the ring back the balls are released.

Interesting, I've never seen one with a button, have to remember that.

 

[RCW]

The mowers (and snowblowers) I’ve dealt with have a ring like @Hugo Habicht pictured.

 

[Roger Fowler]

Thank you all! I will crawl under there, clean it off, and look again.

Roger

 

[Tractor Gal]

Hold the fort! It's a good thing I read the posts on this board. All this time, I was pushing a button like is on all other PTO connections I've used. Apparently, with the statements here, all I need to do is pull back that ring, line up the splines and slide it onto the PTO shaft. "All," I say, "all I need to do." I'm not sure it will be as easy as it sounds but maybe that's why I've had such a hard time re-attaching this mower. The ring does not stay "cocked," for one thing. As soon as I start to slide it forward, the ring goes forward but is not attached yet.

All to say, I hope you get it on! Oops...it's off in this case.

TG

 

[Roger Fowler]

The only PTO shafts for mower decks of those tractors I have seen (not many, I admit freely ) had this ring mechanism.

There are three steel balls inside that are locked by the ring.

View attachment 152843

This is when the ring is forward.

View attachment 152844

When you pull the ring back the balls are released.

View attachment 152845

Interesting, I've never seen one with a button, have to remember that.

 

[Roger Fowler]

I finally got around to tackling this driveshaft again. I do have a locking ring as pictured above. After drowning it with Kroil Penetrant, tapping on it with a hammer and a lot of working it by hand, I still cannot get it to disengage. The locking ring moves a little as shown, it spins, and it rocks. The coupling moves on the splined shaft. I even used a pair of vice grips (carefully) to apply more pressure to move the locking ring back. But the coupling has not disengaged yet. Looking at it carefully I see 2 pins as shown in the picture below. They are 180 degrees apart, one is flush, and the other protrudes maybe 2 mm (.080"). I tried pushing on it, but it seems pretty solid. Any thoughts on next steps would be most welcome. I do plan to do the 50 servicing over the winter, so the deck will be off and I plan to tackle this most stubborn part then. And I should comment that I really do like this tractor.

Thanks in advance,
Roger

 

[Hugo Habicht]

Hi Roger,

I think the three steel balls (and the ring and the splined part) have simply rusted and are now bigger in diameter. Penetrating oil, wobbling and patience are your friends, I would say. The balls are not accessible from the outside for cleaning off the rust I am afraid.

Once you got it off you can disassemble it quite easily. There is a triangular wire spring in the ring part. You have to bend that slightly to get it out of the groove of the splined part. Do not try to get the spring out of the ring. Don't ask

I got 10mm steel balls and found that it could be attached to a new splined drive shaft but I found it very tough to get it off. I bought 9.5mm balls now and will replace them. Functionally both sizes will work fine, the diameter is not critical.

Kind regards,
Hugo

 

[Roger Fowler]

Hi Roger,

I think the three steel balls (and the ring and the splined part) have simply rusted and are now bigger in diameter. Penetrating oil, wobbling and patience are your friends, I would say. The balls are not accessible from the outside for cleaning off the rust I am afraid.

Once you got it off you can disassemble it quite easily. There is a triangular wire spring in the ring part. You have to bend that slightly to get it out of the groove of the splined part. Do not try to get the spring out of the ring. Don't ask

I got 10mm steel balls and found that it could be attached to a new splined drive shaft but I found it very tough to get it off. I bought 9.5mm balls now and will replace them. Functionally both sizes will work fine, the diameter is not critical.

Kind regards,
Hugo

Thank you Hugo.

Regards,
Roger

 

[Hugo Habicht]

One more thing: make sure there is no dirt between the ring and the splined part preventing the ring being pulled back fully. This would make it more difficult too.

 

[Roger Fowler]

Will do. Thanks again.

Regards,
Roger

 

[Hugo Habicht]

The locking ring moves a little as shown, it spins, and it rocks. The coupling moves on the splined shaft.

Hi Roger,

missed this part, sorry. The one I pictured is different to yours but most likely similar construction (maybe you can post a picture from the side).

In the one pictured there are two pins that prevent the ring from turning against the splined part. On mine both pins were broken, I milled the rest out and replaced them. I am afraid I did not take any pictures when I had the coupler taken apart.

If one (or both) of the pins is broken but still protruding it would prevent you from pulling back the ring fully unless it is in a position where the holes in the ring meet the pins.

So try turning the ring while pulling back until the holes meet the pins.

Kind regards,
Hugo

 

[Roger Fowler]

Good morning Hugo,
I went back out this morning to take some more pictures. Looking at it directly from the side I see that there are actually 4 pins. 2 in the U-joint housing and two in the rotating collar. The pictures from the left side show the collar rotated to different positions. And I threw in the picture from the right for reference. I haven't found any holes for the pins to drop into, but maybe they are full of rust and dirt. I will keep looking. Thank you for the information and suggestions.

Regards,
Roger

 

[Hugo Habicht]

Maybe the pins are in the right position, so you cannot see the holes. But then you should not be able to turn the ring against the u-part.

Another thing: you may consider removing the u-joint, I think they have internal clip rings. This way you would get access to the shaft as well and maybe use a puller (with reasonable forces).

 

[Russell King]

I have no real idea how that is supposed to work but it looks like there are pins that act as stops to the rotation (see first and last position. I would guess that one position would be to lock it and the other position is the release position.

 

[Hugo Habicht]

I have no real idea how that is supposed to work but it looks like there are pins that act as stops to the rotation (see first and last position. I would guess that one position would be to lock it and the other position is the release position.

See post #4.

The pins stop the ring from rotating. This PTO driveshaft is rotating at 2000rpm. Pulling the ring unlocks the balls. It is conical inside and pushes the balls towards the centre when released. This holds the coupling in position through the groove in the driveshaft.

Trouble is when the balls corrode they increase in size. Or when the ring cannot be pulled back fully it won't relase, the coupling cannot be pulled off the driveshaft.

 

[Russell King]

Okay sorry for my incomplete statement!

Do either of the positions allow it to move back?

Or other questions would be: What purpose are the pins for? Why are two in the front ring and two in the rear portion?

 

[Hugo Habicht]

Okay sorry for my incomplete statement!

Do either of the positions allow it to move back?

Or other questions would be: What purpose are the pins for? Why are two in the front ring and two in the rear portion?

My understanding is to prevent turning of the ring and guiding it when it is being pulled back.

As I said before, they were both broken on mine and one still sticking out a bit. That prevented the ring from being pulled back fully. Only when I turned the ring so that the stump aligned with a hole I could get it back far enough. My coupling has only two pins pressed into the u-joint part. And the holes were quite deep but full of dirt, had to clean those out too.