Bunton B36T Walk Behind mower - Need help with removing the Drive Pulleys

[Back2Cali]

Hi guys. I'm new to the forums and to mower repair in general, and I could really use your help.

I purchased a used Bunton B36T-11B (Serial Number JJB36T4232) 36 inch walk behind mower (Tecumseh Formula 12 engine
Ohv12 202724b) from an estate to mow some flat property that mostly has weeds on it. For reference, I'm using the parts list located here: http://www.oscar-wilson.com/MANUALS/BUNTON/B36L & B36T JJ-LL.pdf

Short version: I need help figuring out how to remove the Variable Speed Pulley (ref #38) from the drive shaft so I can get to and secure the Drive Pulley (ref #146) (that holds the engine to blade belt) which is loose and causing my engine to blade belt (ref #11) to flip.

Long version: The Mower is pretty solid and ran just fine when I purchased it. When I got it home, however, I got about 30 minutes of work out of it before the engine to blade belt broke. I found parts diagrams on the web and ordered the correct belt to replace it. After a lot of swearing and learning (then more swearing) I was able to get the new belt on but it was so tight that the motor wouldn't turn. Eventually I was able to get the engine to turn and run, but every time I would run the mower for more than 30 seconds the belt would flip around on the pulleys. After reading everything I could find on the web, I figured something must have been messing up the pulley alignment. Sure enough, the engine pulley for the blades was loose enough that I could move it up and down with my hand. I can feel two small holes in the top part of the pulley that I think must have had some sort of set screws that held it in place on the drive shaft, but they are not there. Now I am trying to get the variable speed pulley off the drive shaft so I can get to the engine pulley and figure out how to secure it in place. I was able to remove the lower portion of the variable speed pulley but the drive shaft has a brass variable speed spacer (ref #40) on the shaft and I can't see how to remove the upper portion of the variable speed pulley from the shaft. The brass spacer is so soft that any attempt to move it just mauls the spacer. I attached a photo of the spacer and the upper part of the pulley that I can't seem to remove from the shaft.

Here are my questions:
1. How do I remove the brass variable speed spacer (ref #40) from the drive shaft?

2. How do I remove the upper portion of the variable speed pulley from the drive shaft (or does it come off easily once the spacers are removed)?

3. How is the Drive Pulley (ref #146) secured to the drive shaft?

4. Will this mower cut 1-2 foot tall California Needle Grass, or do I need to invest in something like a brush hog?

I'd love to take this to a dealer, but the closest is about 3 hours away. Thanks for any help you can provide.

 

[Back2Cali]

Maybe the title is too detailed or is it just that no one knows Bunton mowers? I was thinking about maybe using a torch to heat the brass bushings to see if they will expand and come off the drive shaft. Good idea, bad idea? anyone?

 

[Fish]

Buntons were made here in Louisville, and I owned a 36 inch cut in the early eighties, and getting the stuff off of the crankshaft was always a problem.

This mower will not cut what you want to cut too well anyway, get a DR Brushmower or something similar.

 

[Fish]

Yeah, a torch, cutting torch an cutting tools and a bunch of cussing.

 

[Fish]

After reading this again, I think you screwed up big time, as your system sounds like it was working fine. The main problem with this setup, is that the variable speed pulley would freeze in the shaft, and would no longer work right, but the mower
would be locked into one ground speed only. The system works with the variable speed pulley, when you pull back on the speed control lever, it puts tension and the sheaves start moving, changing the ground speed, much like a 10 speed bike.

The blade belt just goes 1 speed, engine speed., so you must have torn the wrong thing down for the wrong reason...

 

[Back2Cali]

Thanks for the reply. I may well be completely off in how I'm going about this.

I had read a post elsewhere that you had written explaining how the variable speed pulley works with tension causing the pulley to separate - effectively changing the "gearing" of the belt and thus the speed of the mower. Great description.

I really have no desire to remove the bushings, but I can't figure any other way to get at the drive pulley that is above the variable speed pulley. Never having seen one of these contraptions before (I'm more of a car guy), I am just trying to get it back to working condition. The problem we are having is getting the drive to blade belt to work properly. The new belt (using the proper part number) kept flipping around when it was engaged. Checking around under the mower, I found that the drive pulley (on the shaft above the Variable speed pulley) was not secured in place on the shaft and could be moved up and down with my fingers. There isn't much room between the mower deck and the variable speed pulley to do much with the drive pulley. Is the drive pulley supposed to be that mobile? Self-centering or something perhaps? I felt two holes on the upper collar of the drive pulley that were at about 90 degrees to each other. I'd love to avoid tearing this thing down further. Is there some secret to aligning the drive to blade belt?

Any insight you have would be invaluable.

 

[dhuff44]

Not sure if you still need help getting the variable speed pulley off or not but I just took mine off a old 32". I removed the bolt on the bottom of the shaft, then removed the snap ring to get bottom half of pulley off which I believe you already got off. I then used a 1/4" drive extension to stick in the bolt hole, then used a pulley puller to remove the top of the variable speed pulley and the brass pieces, it was all one piece. Then I loosened the two set screw's on the other pulley and also pulled that one off. Not sure if that's the right way but I got mine off.

 

[Back2Cali]

Not sure if you still need help getting the variable speed pulley off or not but I just took mine off a old 32". I removed the bolt on the bottom of the shaft, then removed the snap ring to get bottom half of pulley off which I believe you already got off. I then used a 1/4" drive extension to stick in the bolt hole, then used a pulley puller to remove the top of the variable speed pulley and the brass pieces, it was all one piece. Then I loosened the two set screw's on the other pulley and also pulled that one off. Not sure if that's the right way but I got mine off.

I appreciate the post very much. I knew there had to be a way to remove the top of the variable speed pulley off - there's no other way to place or remove the engine. I was just hesitant to possibly break something I could in all likelihood not be able to replace. I'll try the 3 arm puller on it now that I know it can be done. The two set screws are missing from the top pulley (most likely the reason we can't get a belt to stay on that pulley), so we will have to remedy that once we get that bottom pulley off. Thanks for the info! :thumbsup: