B2791A/B2792 MID PTO SUBFRAME

[NorthIdaho3200]

I used the mid PTO on my B3200 for both snowblower and snowplow. This is my issue: The middle driveshaft is supported by two bearings. (Below diagram #030) There is a measurement for the driveshaft location in the manual of 5 1/8" toward the rear. The driveshaft is kept in place by two set screws on each of the bearings. (Below diagram #060) Every spring when I take of the subframe, I wash everything, lube and apply blue loctite. In the winter, I make it about 30 hours of snow blowing before the middle driveshaft get pushed forward, causing it to come disconnected from the rear driveshaft that actually hooks up to the mid PTO. The shaft doesn't have any holes or groves for the set screws to screw into. I am afraid to use red loctite on these setscrews. It just doesn't seem like a good design to have so much depending on the friction of 4 set screws. I was wondering if anyone else has had this issue. I was thinking that perhaps I should take it to a machine shop and have them cut a groove on the shaft or perhaps some shallow holes to keep the set screws from slipping. I have also thought of replacing the set screws with some small bolts but am afraid that I might unbalance the shaft. It is not a hard fix when it happens it is just the shock of having an uncontrolled drive shaft banging on the floorboard.

 

[Dyer retired]

I had the same issue, but didn’t know that middle shaft would move until the front of the driveshaft dropped off and dug into the ground pushing back hard on the mid-PTO housing and breaking the casting,…which then dumped all of the hydraulic fluid all over the frozen ground. The tractor couldn’t be moved until that housing was replaced and the housing had to be 2 day priority shipped, so I could then do the work as the temperature dropped to -15F below,…awesome. That was a $324.00 fix for 50 cents worth of Allen screws! Once I knew that middle shaft was only prevented from moving by the four set screws, I set the shaft where it was supposed to be and used blue locktite on the set screws and tightened them down hard. I then took split locking collars to fit the shaft and placed one behind each bearing and used locktite on those set screws and tightened those down hard. Now the shaft can’t move forward or back and there are no issues with imbalance,…they just spin along with the shaft. I went the entire winter last year with no indication of anything loosening up or moving. I hope this helps!

 

[NorthIdaho3200]

That helps immensely!!! Did you by chance source the locking collars on the net? Do you remember the diameter that you bought? I found out that the blower is Canadian made and is a mix of SAE and metric hardware. Sorry that you lost the PTO housing. Mine just scares the crap out of me when it happens so far.

I had the same issue, but didn’t know that middle shaft would move until the front of the driveshaft dropped off and dug into the ground pushing back hard on the mid-PTO housing and breaking the casting,…which then dumped all of the hydraulic fluid all over the frozen ground. The tractor couldn’t be moved until that housing was replaced and the housing had to be 2 day priority shipped, so I could then do the work as the temperature dropped to -15F below,…awesome. That was a $324.00 fix for 50 cents worth of Allen screws! Once I knew that middle shaft was only prevented from moving by the four set screws, I set the shaft where it was supposed to be and used blue locktite on the set screws and tightened them down hard. I then took split locking collars to fit the shaft and placed one behind each bearing and used locktite on those set screws and tightened those down hard. Now the shaft can’t move forward or back and there are no issues with imbalance,…they just spin along with the shaft. I went the entire winter last year with no indication of anything loosening up or moving. I hope this helps!


View attachment 776277

 

[Dyer retired]

I just looked for a 1” collar on Amazon and ordered a couple. The 1” clamp will lock up tight before the two ends touch. I’ve attached a picture of the collars I ordered.

 

[NorthIdaho3200]

I just looked for a 1” collar on Amazon and ordered a couple. The 1” clamp will lock up tight before the two ends touch. I’ve attached a picture of the collars I ordered.View attachment 776317

Thank you so much sir: A simple solution that I was overthinking.