Shear bolt fixing BX2750D and questions

[sagor]

Well, having bought a used (2013) BX25 with 2750D blower, I decided it would be wise to replace all existing shear bolts with factory parts. Auger was no problem. Previous owner used regular Gr5, and they were all twisted, but never sheared. Next was the fan bolt, which was difficult to remove. Lots of hammering, and it finally came out. Again, regular Gr8 bolt all deformed.
Problem began trying to replace the fan Gr8 bolt. Just would not fit. No matter how much I tried to move the fan back and forth, just would not fit. Ruined a couple of bolts trying to hammer them in. Was ready to put in a 1/4" bolt instead (which would fit). However, I then had the Homer Simpson "dooh" moment, why am I trying to move the fan back to make holes match up, instead of moving shaft forward instead. That was the issue. Perhaps the previous owner hit a few snowbanks to fast or whatever, but seems the shaft to the gearbox wanted to move backwards when the fan bolt was removed. Holes did not align forward/backward. Solution, use a 2x4 wedged between the blower frame on top and the scraper blade on bottom, near the gearbox, against the auger shaft. Near perfect fit. Hit the 2x4 on top a few times with a hammer, and as the 2x4 slides down the cutting edge, the entire gearbox/auger moves forward, just that 1/16" I needed. Fan bolt slipped in with no issues. Finally fixed. Remove 2x4 of course...
Questions:
1) Can the gearbox support bracket (to top of blower) be adjusted to move it all forward just a little bit?
2) What oil grade is required for the gearbox. I might as well drain that and replace it with proper oil as well. To what level?

Thanks

 

[sagor]

Bump...
No answers to the questions for the BX2750D:
Questions:
1) Can the gearbox support bracket (to top of blower) be adjusted to move it all forward just a little bit?
2) What oil grade is required for the (blower) gearbox. I might as well drain that and replace it with proper oil as well. To what level?

(Don't have the 2750D manual yet...)

 

[RCW]

Before moving too much stuff around, check the parts diagram here:

http://www.kubota.com/part/partsList.aspx

Agree to the legal part, and type in your model #.

Seems like there is a collar locked on the shaft at the back of the blower housing to keep it in place.

There is an allen set screw on the front of the gearbox that indicates full level.

I use plain ol' 80w-90 gear oil in mine.

Good luck!

 

[Dave_eng]

Bump...
No answers to the questions for the BX2750D:
Questions:
1) Can the gearbox support bracket (to top of blower) be adjusted to move it all forward just a little bit?
2) What oil grade is required for the (blower) gearbox. I might as well drain that and replace it with proper oil as well. To what level?

(Don't have the 2750D manual yet...)

From what I can see on this forum you have a gear box more typical of a walk behind blower, i.e. a worm gear box full of grease not oil.

Look at this series of posts: http://www.orangetractortalks.com/forums/showthread.php?t=28421&goto=newpost


I dont see any problem moving or bending things to make other stuff align better. These blowers are not high precision items like the inside of an engine.

Dave M7040

 

[07wingnut]

If your shear bolts are deforming before or while shearing, then the bolt being used is not performing as a shear bolt should. The sheared face should be a nice clean shear and the bolt left inside the shaft should just drop out when the holes are aligned. OEM shear bolts should work well, but I found their cost a little over the top. Grab a fistful of Gr5 and Gr8 bolts, and groove your own, takes a few minutes, saves $. Use a bought one to locate where the grooves should go.
For the gearbox use hypoid gear oil.

 

[RCW]

I use OEM shear bolts, but seldom break them. Many make them like wingnut does. Here is a page from operation manual. I don't have WSM for the blower.

Sent from my iPhone using Tapatalk

 

[sagor]

If your shear bolts are deforming before or while shearing, then the bolt being used is not performing as a shear bolt should. The sheared face should be a nice clean shear and the bolt left inside the shaft should just drop out when the holes are aligned. OEM shear bolts should work well, but I found their cost a little over the top. Grab a fistful of Gr5 and Gr8 bolts, and groove your own, takes a few minutes, saves $. Use a bought one to locate where the grooves should go.
For the gearbox use hypoid gear oil.

The old bolts were not shear bolts, just regular GR5 and GR8 x 2-1/2 inch. I know they were the wrong ones, that is why I replaced them with factory ones, for now.
Yes, I've tried making my own. The internal diameter of the necked down part on both factory bolts is close to 1/4". I put my bolts into a drill press (after marking the areas to file down with marker), and use a simple hacksaw blade to cut it down to about 1/4" while the drill rotates it. Not as neat, but for sure they will shear at that spot. The issue with the GR8 is they have only one neck, but the other shear spot (I suspect) is the threaded part, which happens to be close to 1/4" diameter as well. I took a 2-1/2" GR8 bolt and made two groves, the second close to where the Kubota 2-1/4" bolt thread ends. Hard to find 2-1/4" bolts around here.
Thanks for the advice.

 

[sagor]

I use OEM shear bolts, but seldom break them. Many make them like wingnut does. Here is a page from operation manual. I don't have WSM for the blower.

Sent from my iPhone using Tapatalk

Thanks RCW, that is just what I was looking for.