MMM problem...what to try next

[pilonidal]

The gear box pulley on the MMM will not stay in place more than 3-4 mowings. It slides down the shaft. When it happened again about 6 weeks ago I replaced the Allen head key screw with a small square head screw so I can really torque it down. I thought no way that is moving. I even took a punch and dimpled the metal on the end to help lock it in place. I always check it before I start as the pulley will set on the deck and still spin, I notice the change in sound from it when it does drop. This time the pulley stayed in place but the pulley key slipped down and was gouging the deck, WTH I thought. I use lock tight on the set screw to. Anyone else have probs with their gear box pulley falling off? The weight of the pulley, vibration and gravity keep pulling the pulley down the shaft. Now I am looking for pulley with 2 set screws, one for the pulley key and one to screw into the shaft. It does make sense to use a pulley with 2 set screws as ultimately only the friction between the pulley key and the shaft are what keeps the pulley in place. Any dealers seen this issue arise?

 

[coasterez]

Your tractor is brand new, right? What's your dealer doing to help? Clearly something's not right.

 

[pilonidal]

Well, the deck is 2.5 years old and the dealer whom I purchased it from is 2 hours away. It did this a couple of times last year and more frequently this year.

 

[depratt_equip]

do you have the side or rear discharge.... never seen the problem. I thought they had to set screws on them. I have both in the shop... will check.

 

[pilonidal]

It's a rear discharge.

 

[BTI]

I believe there are 2 set screws............

BTI

 

[County Sawyer]

Take the pulley to a good industrial supply house and replace it with one that uses a taper lock from Browning or some such brand. My mowers have taper locks on all of the pulleys and they never move.

 

[AutoUnionTypeC]

The gear box pulley on the MMM will not stay in place more than 3-4 mowings. It slides down the shaft. When it happened again about 6 weeks ago I replaced the Allen head key screw with a small square head screw so I can really torque it down. I thought no way that is moving. I even took a punch and dimpled the metal on the end to help lock it in place. I always check it before I start as the pulley will set on the deck and still spin, I notice the change in sound from it when it does drop. This time the pulley stayed in place but the pulley key slipped down and was gouging the deck, WTH I thought. I use lock tight on the set screw to. Anyone else have probs with their gear box pulley falling off? The weight of the pulley, vibration and gravity keep pulling the pulley down the shaft. Now I am looking for pulley with 2 set screws, one for the pulley key and one to screw into the shaft. It does make sense to use a pulley with 2 set screws as ultimately only the friction between the pulley key and the shaft are what keeps the pulley in place. Any dealers seen this issue arise?

I have had the same many times; in fact I’ve had to replace my first pulley as I didn’t catch in time and the key rounded off and elongated the pulley center. My solution has been blue locktight on the setscrew and key as well as a set of t-handled allens for maximum torque on the allen. It also helps to start out with a fresh key. So far it's held through the summer as I last reset it this spring. It is a design weakness and I too have thought of a pulley with two setscrews but abandoned the idea, as I didn’t want to score the shaft so badly as to make removal difficult or replacement necessary.

Regards, Jamie

 

[tlbuser]

The weight of the pulley, vibration and gravity keep pulling the pulley down the shaft.

Make a brass spacer to place over the shaft between the pulley and deck

 

[pilonidal]

Make a brass spacer to place over the shaft between the pulley and deck

There is no room for a spacer on the shaft. Guess I'll put some lock tite on the key also. I still want a 2 set screw pulley though. I only have another mowing or 2 before I call it for the year. I am glad that I am not the only one though with this problem. Beginning to think I was an idiot for not being able to keep this darn pulley in place.
The pto shaft to the gear box has a 2 set screws on top where it shouldn't really be much of a problem but the hanging pulley only has one set screw. Things that make you say "hmmmmmm".

 

[BTI]

The ones that I have had had a 2 set screw pulley on them.
One where the key is and one approx 90 degrees offset.
If you are going to buy a pulley for it, I would do what County Sawyer said.
Those really aren't bad priced and they won't slip.

BTI

 

[coasterez]

Another alternative: drill and tap your existing pulley to add a second set screw.

 

[malk315]

Hi-

I saw your post and wanted to check mine to see how that pulley is setup.

I have a DMM60 which is a 60" side discharge deck. In the manual the exploded parts diagram shows a cone shaped spacer type thing (taper lock bushing in the parts list) w/ slot for woodruff key and "plug" (it says plug in the parts list, but I imagine it functions as a set screw). The taper lock bushing's smaller diameter is at the top (engages bottom of pulley) and larger diameter towards bottom. In the parts list, it says it requires 1 taper lock bushing, 1 woodruff key, and 2 "plugs" which I think are set screws. So even though the picture shows one plug, the parts list says two are required. So I imagine my center pulley is held w/ two set screws and hence the reason I probably haven't experienced problems -- although my deck has only about 10 mowings on it. (purchased tractor a few months ago -- it has about 23 hours on it).

Perhaps you could check if the bushing, key, and "plugs" for my deck will work on your deck. Part #'s:

W3021-34171 - Taper lock bushing (1 required)
W3021-33141 - Plug (2 required)
05811-00519 - Key (1 required)

Other numbers of interest:

W3021-33111 - Bevel Gear box - the entire deck transmission
W3021-34162 - Big pulley that's involved with the 3 parts above

If these are compatible with your deck, you may be able to switch to the parts.

Good luck

-Eric M.

CK20 HST
60" MMM Side Discharge
KL120 loader
23 hours

 

[pilonidal]

Thx for the reply's and idea's, those part numbers maybe the ticket. I'll have to check with the dealer just to make sure they will work also. thx