Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking

   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking #1  

mholka

New member
Joined
Nov 25, 2014
Messages
10
Location
Petoskey, Michigan
Tractor
1991 Ford 2120
Okay I am having issues and the dealership has not been able to figure this out either.

I have a Kubota B2650 and Snow Blower B2781B. There is a bolt in the side of my PTO gear box that is used to provide tension on the sprocket to keep the chain tight. And it keeps breaking. I had this happen last season (its 3 seasons old bought brand new). SO i talked to dealership got a new bolt, had to tear this thing apart to get it back together. Made sure everything was aligned and running. Mid season everything came lose again. I tore it all down and re tightened everything down and it was fine.

Jump to this season - first time out tensioner broke again and i had to rebuild it all again, and everything seemed fine. 2nd time out and the dam thing literally exploded with parts all over the driveway. Plastic casing on drive shaft shredded, broke the protective guards, broke chain and I assume its because tensioner bolt broke again under use!

So I filed a claim with Kubota Insurance and dropped it off for repair. Now almost 2000.00 in repairs and the second time I take it out to remove 3-4 inches of soft snow on my 1/4 mile driveway I senses a vibration, shut it all down and the darn tensioner bolt is broken AGAIN!

There has to be something I and the dealership is missing! What would cause that to break again? I am assuming some ungodly torque or force is breaking it. See pictures attached.

Does anyone have ANY ideas? I am desperate. In the middle of snow season and we have gotten over 40 inches of snow in December.

FYI - Now dealership wants me to get machine and snowblower into the dealership. At My cost! I do not have a trailer big enough and would cost over $200.00 each way!

I am so freaking irritated. Been out of work since June. I purchased a grading pusher blade a week ago to get by (1800.00) but now they want the whole kit and kaboodle! I'm screwed!! snowblower.jpgSnowBlowerModel.jpgTensioner Bolt.jpg
 
   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking #2  
How much tension was on the chain?

Perhaps the gear is not concentric with shaft and causing the chain to have slack and become tight as it is rotated.

Are the two chain sprockets aligned?
 
Last edited:
   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking
  • Thread Starter
#3  
I have added some additional pics with notes on them to explain more details.Drawing.JPGDiagram.JPG
 
   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking
  • Thread Starter
#4  
I did not check the chain because I picked it up 2 days ago from dealership. No way to check it without disassembly.I did spray it after each use with aerosol chain lube.
 
   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking #5  
Checking the alignment of the sprockets is difficult even when the protective covers are removed it's difficult to see. I don't think the chain should be too tight and the tension needs to be checked throughout the rotation of the big sprocket.

When working on my Dad's B2781A (chain replacement) I've noticed the big sprocket causes chain tension to vary slightly as the sprocket is rotated. The tension needed to be adjusted when sprocket position was in it's tightest position.

Was bolt #25 retightened after setting the sprocket tension?

Is the driveshaft (front PTO) walking fore/aft causing the smaller sprocket to move out of alignment with big sprocket?

The root cause of misalignment could come from almost any part of the blower housing. Hopefully they will take the time to thoroughly investigate what is occurring with this unit.
 
   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking
  • Thread Starter
#6  
Checking the alignment of the sprockets is difficult even when the protective covers are removed it's difficult to see. I don't think the chain should be too tight and the tension needs to be checked throughout the rotation of the big sprocket.

When working on my Dad's B2781A (chain replacement) I've noticed the big sprocket causes chain tension to vary slightly as the sprocket is rotated. The tension needed to be adjusted when sprocket position was in it's tightest position.

Was bolt #25 retightened after setting the sprocket tension?

Is the driveshaft (front PTO) walking fore/aft causing the smaller sprocket to move out of alignment with big sprocket?

The root cause of misalignment could come from almost any part of the blower housing. Hopefully they will take the time to thoroughly investigate what is occurring with this unit.

I'll dive into it tomorrow and get more pictures and measurements of the chain and various rotations of the main sprocket.

I think the #25 BOLT was re-tightened once everything was realigned. I know I had to do it 3-4 times before I could get it aligned properly and bolts all secured.

Thank you.
 
   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking #8  
I can't tell from diagram but is the tensioner on the correct side of the chain? Could just be a design flaw.
 
   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking #9  
Question for the OP: When you re-installed everything did you disconnect the PTO at the blower and manually spin the augers to see if everything was moving smooth with no binding? If you set it up right it should move smooth as butter.

It also looks like you store the tractor and blower outdoors. If possible try putting the tractor and blower in a heated garage until everything melts and is clear. Before you hook up the chain make sure every motion moves freely and smoothly...from augers to sprockets. If your tensioner sprocket is binding with nothing on it that might be your problem.

If the tensioner has little or no bearing and is jammed up full of ice that will lead to premature failure due to lack of lubricant.
 
   / Kubota B2650 and Snow Blower B2781B Tensioner for PTO Gear box keeps breaking #10  
Mholka,

Any luck finding a remedy or root cause?
 

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