106 mule drive belt kicking off spring pulley

[zachbradshaw]

Hello all, long time lurker here. I have a cub 106 42 inch mowing deck that I have been working on for a year or so. When I bought it the previous owner said the mower deck would slip the mule drive belt and he thought it was because the pulleys were rusted up on the deck and mule drive. I have wire brushed the deck pulley, replaced both mule drive pulleys. I installed a cub belt part number 490489-R2 through the faq section here. I installed the belt this afternoon and found it was tight going on but I got it slipped on. As soon as I engaged the pto the belt slips off the spring tensioned pulley/ right side pulley of the mule drive. Now the only problem I can see is that my pulley bracket has worn on its pivit shaft to much and allowing the pulley to be canted enough to throw the belt. I do have both pulleys at the correct 90 degrees from the pto even tho the belt is hard to get in when fully unadjusted. Do I have to much tension?? Any help would be appreciated and I hope this makes since. Thanks for your help.

 

[abthomas]

right width belt and right pulleys for belt ? if pulleys are worn and sloppy it will throw belt also ,I had a problem a few years ago with a belt that was 1/2 " wide but needed one 3/8" and would throw it off the pulley !

 

[Beltrack]

I had a similar problem with a 109. A cotter pin let go and the shaft and pulleys disassembled themselves. Many of the bits and pieces were lost in the grass. I ordered new stuff from CCS and began to set things right again. That is when I realized there were at least two ways to reassemble the pulleys - - the right way and the wrong way. I can’t help anymore than to say it took a lot of study on Google images and diagrams from Cub Cadet parts and service manuals to do it properly. As I recall, if done improperly, the belt arrives at one of those pulleys a quite a severe angle which I assume could cause it to jump off. I never operated mine with the improper setup, so I don’t know if the belt would have jumped. I determined just by looking that the alignment didn’t seem right.

 

[Beltrack]

I am referring to the idler pulleys in the above. Should have made that clear. Sorry.

 

[kmcconaughey]

Check the deck subframe for wear, where the front slips into the mower deck clevises. Also check the clevises themselves for wear. If there is too much wear on these parts, the mower deck will be nose down causing the belt to derail. You might be able to readjust the clevises to level the deck but if it's worn badly you'll have to weld up the deck hanger and grind to shape to rebuild the worn area.

Note circled area, there's a second one hidden by the main frame, check both for wear.

 

[kmcconaughey]

Re read your post, the pulley brackets will wear the rod and the hole in the brackets and then they pivot out of alignment. I replaced the rod on one of my deck subframes and welded up and drilled new holes in the brackets to bring them back into alignment.

 

[kmcconaughey]

And, yes, it's possible that you have too much tension.

 

[zachbradshaw]

Thank you for your reply’s. The belt is a 3/8x80 I believe I’ll have to go back and look the part number back up through charlys faq section here. The pulleys are the same as the old ones that were on it. I know they could have been replaced but the tractor as a whole looked to be original when I got it. Now that was last year when I had the mule drive off to do clutch work and wiring harness and a little painting. I think I got them back how they were. I will try and get a few pictures but I believe the circled below is what’s going on. Also is 3/8 x 80 the correct size?

 

[zachbradshaw]

Here are a couple pics with the belt thrown. It doesn’t look to canted now but with the belt on you can tell it’s not straight

 

[kmcconaughey]

Yes, that should be the correct belt. And that pulley does look a bit off, check the brackets and rod for wear. Nice looking 106!

 

[zachbradshaw]

Thank you, I believe I am going to take a trip to tractor supply and see if I can find a sleeve that will fit over the rod and drill the hole out on the bracket for now and that should straighten everything up. Thanks for the help!

 

[kmcconaughey]

If the rod is worn, it should be easy enough to grind the ends, slide it out while removing the brackets, drill any holes for the cotter pins and such in a new rod, repair the brackets, slide the rod back in while installing the brackets, install the pins, and weld the rod in place. Provided of course that you have a grinder, a drill, and a welder...

 

[Greg Riutzel]

This is the 1st I actually seen a number associated with deck belt tension. Thanks Kraig. All my literature shows only the tension gauge or a different style in pulley brackets & tension spring. My drive is missing the gauge but a number now should come in handy, unless different mowers have different belt specs.

 

[zachbradshaw]

Thanks, yea got all that at work I forgot about the rod being welded in I might as well do like you said and do it right. I didn’t know about the tension either. I just had read about pulleys needing to be 90 degrees from the pto to operate correctly

 

[kharvey]

One other thing to try is reverse the belt so it is pulling the opposite direction. I had trouble when i switched from snow duty to mowing and it would throw the belt. Some belts like one direction better.

 

[zachbradshaw]

I will give it try thanks for the tip.

 

[mgwin]

Zach,
Welcome to the forum!

 

[mfrade]

Thank you, I believe I am going to take a trip to tractor supply and see if I can find a sleeve that will fit over the rod and drill the hole out on the bracket for now and that should straighten everything up. Thanks for the help!

I did just that on my 73. The "brackets" the pulleys mount onto had the holes oblong and the shaft had the wear in the same spots, So I removed the rod, found a piece of tubing or pipe to go over the rod, drilled new holes on center in the brackets and sleeved the brackets.Added a spot weld to the sleeve and reassembled. That was maybe 15 or 20 years ago.. works perfect!

 

[dfrisk]

ZACH - One thing else We discussed here years ago is the mule drive belt really needs to be an IHC or Cub Cadet belt. The belt has to be flexible to make the quick direction changes at the speed of mowing. I tried to save some time 30 years ago and went to a Motion Industries store 4 miles away and bought a DAYCO belt that half the price of the IHC belt at my local Cub Cadet dealer 20 miles away. The Dayco belt would jump off that right side pulley in about 2-3 seconds. I ended up going to the Cub Cadet dealer anyhow. That was on a 129 with 44A deck. I know MTD made a change to the mule drive belt for my #72 with 38" 3-blade deck years ago, made the belt narrower a tiny amount, and it fits and runs the deck fine, but with my higher HP engine in my #72 it slips the belt easier, and a slipping belt fails much quicker.
And while your there looking at the mule drive idler pulleys, spin them by hand to make sure they spin free. I've had them shooting sparks I didn't know about till I was mowing after dark. I kept two spares on hand, and one for the 982& 50C deck.

 

[zachbradshaw]

Yea all the reading I have done since trying to restore this tractor I ordered a cub belt. I ended up putting a sleeve in the mule mule on the right hand side and it tightened up the slack a considerable amount. It did fix the belt issue although I ran a couple laps yesterday to make sure the belt did fine. The engine started to big a little after the bearings in the deck heated up so I believe it’s time to replace the spindle bearings and shell more money out to get the yard mowed and I’m done to just this tractor now. Thank you to everyone for their response it is greatly appreciated. As for the mule drive I was kind of in a hurry at work to do the sleeve repair. I’m eyeing a nos drive from ih cub parts to replace it with