42" Mower belt problem

J

Jim in SC

Well-known member
Hi, second post on this part of the forum. I just posted a separate question about steering that I need help with too.

But I need help with a mower problem also. I have a newly purchased '69 Cub Cadet 106 with a 42" mower attached. The mower is iffy. I "patched" some large rust spots on the deck with sheet metal, improvised an left end piece and runner and wheel bracket on the right side, and bought/installed new deck wheels. I pulled the wooden roller on the front of the deck and freed it up and lubed it. Took the mower out for a test spin and it mows fine, but it keeps throwing the large drive belt. I tried tightening it with the adjusting screw on the front of the tractor, which helped some, but it still throws the belt, just not as often. I'm pretty sure the spindles are spinning free. The serial/model number on the mower is 421U1116, if that helps any.

Any advice?

Thanks!

Jim
 
There's several things to look at, all of which have to do with the mule drive assembly. First, lower/remove the mower deck and pull the mule drive assembly off (the hanger mechanism that slides out the front of the tractor) and put it up on a work bench. Inspect the two idler pulleys where the belt comes down from the PTO, makes the 90-degree turn and heads back to the mower. These pulleys wear out quite often, so I'd bet the bearings are bad in them letting them flop around. If they feel ok, then check the alignment of them and the axle bolts that hold them to the mounting brackets. They should be fairly straight up/down, front/back. I see these get twisted in their mounting, so their at a weird angle to the tractor, and/or the axle bolts are so worn that the pulley just flops around. You may have to straighten out the mounting brackets and/or buy new ones, and install new bolts. Also check the rod at the top of the hanger that the adjustment pulleys mounting brackets hang from. Often that rod is worn so bad that even a new mounting bracket will flop around on it.

Next, before you re-assemble things, look at an owners manual to see how it goes. I've seen the pulleys mounted a dozen different ways, and there's only 1 right way. They should be mounted such that the belt comes straight down off of the sides of the PTO clutch, no angles, not out to the sides of the tractor or pushed towards the middle, straight down. Trust me, look at an owners manual to see how the parts go back together and don't rely on "how it was"!

All of these things are pretty much the first thing I look at before re-mounting a mower deck on a Cub Cadet. If any of the above items are not right, it will just keep throwing the belt. I will often just disassemble all of the mule drive assembly and put it back together with new pulleys, bolts, washers, etc.

If all of these things are perfect (and I'm 99% sure you'll find their not), the belt could just be the wrong one. However, if you had it running at all, the belt is likely fine.
 
GLTractorman, thanks! Whew. Got my work cut out for me it sounds like! I'll start out where you suggest and hope for the best. Otherwise I'll wait to tear it completely down after grass mowing season. I hate it, but I guess i'll have to depend on my JD mower to bear the brunt of grass cutting for this year...

I really appreciate your quick and knowledgeable reply!

Jim
 
Update on the belt problem. I took the mule off today (once the rain quit and the sun came out - 1st time in like 2 weeks and after 13+ inches of rain...) and found that the pulleys are okay, but the pulley hanger on one side is bent and the shaft holding it is worn almost half way through. Not good. I suppose I could take it to a machine shop and get it repaired, but am instead on the lookout for a narrow frame front hanger assembly. I have my eye on one from a 124 and THINK it is the same as the one for the 106...

Any thoughts on that?

Jim
 
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