John Deere 30 inch mechanical tiller disassembly problem

[Al_W]

I'm trying to get the chain sprocket out of the tine shaft on a 30" JD mechanical tiller. The sprocket and spindle will spin on the tine shaft and slightly move out but will not pull further than 1/4 inch. I don't see a way to get in back of the sprocket to either pull it or push it out. Anyone ever do anything similar? Am I overlooking something obvious?

 

[TractorTech]

From your description and pictures, I would say that the bearing is stuck on the shaft. Did you unscrew the set collar, #7, on the bearing?

 

[Al_W]

From your description and pictures, I would say that the bearing is stuck on the shaft. Did you unscrew the set collar, #7, on the bearing?

There is no longer a set screw on the collar and it is still stuck on the shaft. The bearing and race are mostly broken off anyway and the problem is the shaft of the chain sprocket that goes into the tiller shaft will not come out. The set collar would only keep the bearing in place and not the chain sprocket from being removed. I'm still working on it.

 

[oldnslo]

When shaft stops moving does it still turn freely? Just curious if over the years some crud has built up inside the tiller tine tube or if tube is slightly bent from use.

 

[TractorTech]

There is no longer a set screw on the collar and it is still stuck on the shaft. The bearing and race are mostly broken off anyway and the problem is the shaft of the chain sprocket that goes into the tiller shaft will not come out. The set collar would only keep the bearing in place and not the chain sprocket from being removed. I'm still working on it.

I'm missing something, but when you removed the setscrew, did you unscrew the collar from what's left of the bearing's inner race? The collar bites into the shaft to hold the bearing.

 

[Al_W]

I'm missing something, but when you removed the setscrew, did you unscrew the collar from what's left of the bearing's inner race? The collar bites into the shaft to hold the bearing.

The collar is still on the sprocket shaft but there is so little of the bearing left that with the flange bolts removed none of that--not the collar or the bearing--would keep that shaft from being removed IF it would only move freely. Anything left that is still on the sprocket shaft easily fits through the hole of the tiller side body.

 

[Al_W]

When shaft stops moving does it still turn freely? Just curious if over the years some crud has built up inside the tiller tine tube or if tube is slightly bent from use.

When I pull it out that little bit and it won't go further it is stuck at that point and will not turn freely. I'm at the point where I am almost ready to give up on it. I'd like to put a bomb under it and blow it up. Getting really frustrated because I have other things to do and can't spend all of my spare time with this.

 

[TractorTech]

Okay, so I think then that the holes that the retaining bolts go through a galled the shaft? If so, take a drill larger than the hole and use it to clean up the raised area of the shaft. To pull the shaft, fashion some wedges out of wood or stacks of metal behind the sprocket to help pry the shaft out.

 

[Al_W]

I finally got it removed! I don't see anything obvious on either the inside of the tiller tine shaft or the sprocket rod that I finally got to come off. I had to remove some tines and get the bearing housing off on the other side of the tiller shaft in order to be able to twist, pull, wedge and cuss the sprocket off but it finally saw things my way. I'm uncertain about several things though. The sprocket still has the locking collar mounted to it and it is holding what I assume are the remnants of the ball bearing assembly. I shouldn't have too much trouble getting the collar off but the rest of what is left on the shaft--is all of it something to be removed or is any part of it something that belongs on that sprocket rod? I think it all has to go. I had hoped that John Deere had an actual photo of the sprocket but the only photo anyone found is completely bogus and might be some figment of ai's imagination. The pictorial sketch isn't much help either. Also--do I try to lightly sand the sprocket rod? How about the inside of the tine shaft? And when it comes to installing the bearings can I use a socket that would fit on the inner race and push it onto the shaft or lightly force it with a hammer? Is there some sort of tool I should be using to install the bearings safely onto the shaft? Even though the bearing on the opposite side seemed to be working it is not totally quiet so I'm going to replace that one as well while I have the opportunity. Then there is one more point bothering me--the grease that used to be under the chain cover and on the chain. The grease I removed was not anything resembling grease. It was dry and almost powdery. Has anyone ever seen that?

 

[TractorTech]

The locking collar and the inner race of the bearing are still there as you suspect. A cutting torch will take those both off easily, but if you don't have one, a propane, preferably a MAP gas torch can be used to heat both pieces to a orange, red color, then cooled to loosen them up to beat off with a hammer.
Sand the shaft to remove burrs. A socket or pipe of the diameter of the inside race is proper to tap the new bearings on to the shaft. Yes, replace both bearings. There appears to by a snap ring or something beyond the bearing race. The book doesn't show anything AND it doesn't show a seal. There should be a seal in the case to keep the grease in and dirt out. I don't see one, so the tolerance between the shaft and housing should be very close and no wear at this point.
The "dust" in the chaincase is not a good thing and indicates that the grease leaked out. At this point, clean the case, chain and sprockets thoroughly then use corn head grease, such as Tractor Supply Super S #00 Cotton Picker Spindle Grease