broken PTO

[oldgrayfellow-HT]

Tried out my used RS1200 tiller for the first time today, on my YM 186D. Had been tilling my 50 foot garden (soft, sandy loam, no rocks, a few minor roots) for 3 passes, stopping the tiller at the end of each pass.

At the end of the 3rd pass, i raised the tiller, stopped, and clutched to disengage the PTO, to find that it would not disengage. There was no neutral-- i could shift the PTO to high or low speed, but neutral position seemed to have disappeared.

After 5-6 attempts to find neutral i shut off the tractor and took a look at the back, to find milky green fluid running out of the rear end around the PTO shaft. In removing the tiller PTO coupling, i found that the PTO shaft coming out of the tractor had apparently broken loose internally, and could be flopped around from side-to-side by hand.

OK, what the heck happened and why?

And then, what do i do to fix it? I have the service manual, and am willing to tear into it, but it will be easier if i already know what i'm looking for...
Thanks loads.

 

[Norm-HT]

No way to know about damage or repairs without hands-on inspection. Do you have either a slip clutch or shear pin to protect the pto?

 

[oldgrayfellow-HT]

Well i pulled apart the PTO today; the only thing broken or damaged i can see so far is that a thin metal ring (a keeper ring of some sort?) was spread/broken/twisted and out of place (see photo # 2635).

The whole PTO shaft had slid forward (toward front of tractor), apparently because the forward bearing (near top center in the photo) had slid out of its bore in the casting. You can see the forward bearing out, slanted and above the plane of the casting near top of the photo (sliding forward equals sliding "up" in this picture).
There is a groove in the outer race of this forward bearing. Seems like it might be for a circlip that would prevent the bearing sliding forward this way, but no circlip was present, nor did any appear to be lying in the transmission housing.

The split/twisted metal ring (near the point of the bamboo skewer) seems too thin to have been a keeper ring-- too thin for the width of groove in the bearing. (The groove is visible near the bottom edge of the bearing, above the plane of the casting in the photo.

In photo #2645, I have slid the bearing back partially into its bore, and the point of the bamboo skewer is resting in the groove.

So, does anyone know:

1) if there should be a circlip for that groove, or if not, how is the PTO shaft held from sliding forward through the bore as it did.
2) what are the function and proper location of the existing damaged thin ring
3) what else, if anything, i should check

Thanks

 

[winston-HT]

That is the snap ring you are pointing at. That is most likely a H6207-snr bearing. Have to wonder why it came out? Did you have any big impacts on your pto? Is it possible your tiller pto shaft is a little long and putting pushing pressure against your tractor pto shaft? If the ring is to thin it could only be from the bearing turning in the housing. I can't tell from pictures if that might have happened. If it didn't, I would say the ring is not to thin. I would examine everything closely, especially that bearing. If no damage exists, put it back together. The snap ring is what holds the bearing from going forward.

 

[oldgrayfellow-HT]

Thanks Winston,

There were no sudden impacts at all on the tiller/pto. The soil is pure sandy loam with zero rocks and only a few small diameter roots.

I think the tiller PTO shaft had enough "short direction" room to slide from the position at installation. I didn't pay attention to whether it may have been bottoming out when i raised the tiller. Maybe a possibility, i'll definitely check that out before using it again. I was using a tiller top bracket made for a YM1500, which i am told would maintain the correct tiller geometry during lifting.

I don't think the outer race of the bearing had been turning in the housing-- both the inner and outer bearings turn as smooth as silk with my finger, and there didn't appear any scoring on the outside of the outer race.

If that snap ring is the keeper ring for the bearing, so be it. It just seemed odd to me that everywhere else inside the PTO, all i saw were circlips that fit their grooves quite precisely, but this "snap ring" seemed too narrow for the groove (like half the width maybe), had no holes for a pliers, and the end surfaces of the ring were not even square, but appeared to be angled.

 

[winston-HT]

Those outside bearing rings don't have holes for removal . That is normal, however, I sure thought the rings did fit pretty snug. Aaron or some of the gurus might could confirm this for us. This is for a ym2000, may or may not be same as yours, Aaron can probably tell you.
<LINK_TEXT text="http://www.hoyetra...en=PROD&amp;Product_Code=6207-SNR</LINK_TEXT>

 

[Anonymous-HT-0-HT]

no telling what may have been used in the past, your description sounds like a type of clip though.