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Shop = My Therapy
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Discussion Starter · #1 ·
Any help is much appreciated. This is on a 60" Cub Cadet 3235 deck.

The deck keeps throwing the belt off (under) the center spindle pulley.


Here is the belt configuration. The problem idler is the one next to the center spindle.


I replaced both the spindle pulley and idler pulley. The old idler pulley seemed out of balance and I think the bearing was starting to go out. The spindle pulley had a wore spot on the bottom edge.


After putting on the new pulleys & a new belt (the idler pulley bolt is perfectly straight) - it didn't change anything when I turn it over. Itthrows the belt almost instantly when under power.

When turning it by hand the correct direction - the belt runs low on the idler which is causing it to slip under the spindle pulley. When I turn it backwards - the belt runs right down the middle of the idler as it suppose to do. See the below video of me turning it by hand in both directions and watch the belt as you will see it change it's line around the idler as I turn it in each direction. The correct way is when the belt is moving to the left around the idler and onto the spindle.
http://s596.photobucket.com/user/du...80-5031-00000A0B62F64760_zps7f0766b4.mp4.html

I also checked the pulleys for being level with each other, They are close. The idler pulley is about a 1/16" off matching the spindle pulley keeping the face where the belt runs a little higher (angle wise) then the spindle pulley.

Spindle pulley:


Idler pulley:


Could that little bit be causing this? If it is, I think I will have to bend the deck surface to fix it.

Thoughts?
 

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Evidently the belt is riding low in the new idler just as it was with the old pulley with the shined / polished look as evidence. Rather than attempting to bend the deck consider determining if a shim would work to align it better. It will need to be tipped enough to keep the pulley edge from grabbing the belt.
 

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The fact that it begins to run astray one way, and correctly if you reverse it, says to me that under load something could be tilting out of level due to torque. Did you remember hitting anything hard, like a curb, rock or stump? Can you think back to a time when this wasn't happening? Something changed by collision or wear.
 

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The fact that it begins to run astray one way, and correctly if you reverse it, says to me that under load something could be tilting out of level due to torque.
This.

But I also think you may be able to resolve the problem by shimming the pulley. As little as 0.032 could make all the difference.
 

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My first observation is that there is not much lip on that idler. Alignment is going to be critical. Another thought is belt tension......how is the spring?? Also consider that a worn belt is not going to stay on track as well as a good belt. When does it generally come off? At start up or under heavy load? If start up is the problem, lower your rpm when engaging the pto. So many factors!!
 

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Shop = My Therapy
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Discussion Starter · #7 ·
Evidently the belt is riding low in the new idler just as it was with the old pulley with the shined / polished look as evidence. Rather than attempting to bend the deck consider determining if a shim would work to align it better. It will need to be tipped enough to keep the pulley edge from grabbing the belt.
I have tried shimming it higher and lower with no improvement. It is running middle to middle right now. I tried turning the pulley over as well.

Is it a cub belt?
No, it is not. But it is exactly the same size 5/8 x 124 as CC parts calls for. I run belts from this company on several deck with 100% success with them. It is just $55 cheaper.

The fact that it begins to run astray one way, and correctly if you reverse it, says to me that under load something could be tilting out of level due to torque. Did you remember hitting anything hard, like a curb, rock or stump? Can you think back to a time when this wasn't happening? Something changed by collision or wear.
I've never used this deck or tractor. I bought it not running the best with the deck off. As shown above the spindle pulley is close to the same level, but not exact. Maybe a 1/16" off.

Everything spins very freely by hand and the tractor starts the deck at low throttle without any issue until the belt flies off within a couple seconds. The belt is not rubbing any where either.
 

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Shop = My Therapy
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Discussion Starter · #8 ·
My first observation is that there is not much lip on that idler. Alignment is going to be critical. Another thought is belt tension......how is the spring?? Also consider that a worn belt is not going to stay on track as well as a good belt. When does it generally come off? At start up or under heavy load? If start up is the problem, lower your rpm when engaging the pto. So many factors!!
New factory CC idler (I thought the same thing). Tension & spring are good. Brand new belt (the one that looks old, was brand new - that damage was done in about 30 seconds the first time I started it). Comes off within seconds starting it at low throttle (just above idle) with no load. Trying it now with another new belt on it.
 

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Discussion Starter · #9 · (Edited)
Another thought is belt tension......how is the spring??
This brings up a good point. Do I have the tensioner spring hooked in the right place? To hook it on the bolt near the right spindle pulley is really hard to do and seems to tight, but maybe that is how it is suppose to be??? I have it hooked to the cover bracket right now. Can anyone confirm where the tension spring should be hooked too?

 

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With those two pulleys being in that close of proximity to each other they will need to be parallel to within a gnat's ***. According to the bubble of the level pictured they are not. Put the new belt on and attempt to place the belt in the center of the idler pulley in question. Now rotate the pto shaft by hand in the normal direction of operation and watch the belt walk to the position it wants to reside in.

When you get the belt back side to run approximately centered in the idler pulley, ( doesn't have to be perfectly centered ) and not travel to the edge and nothing else is wrong with bearings etc. you may be able to use this piece of equipment.
 

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I agree with Senior C.
you said the belts are not rubbing any place...then it almost has to be pulley alignment.....maybe one was replaced and not spaced right ?? its hard if you dont have any history
good luck
 

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Looking at the parts blow up it looks like the tension spring is not at the right location. The spring is showing attached to bolt or pin 17 in the picture. With the pulley's that close together they need to darn close to bang on.
 

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If you cant see it the pic got from artstree 3235 60
 

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Discussion Starter · #14 ·
Thanks. I think I'm going to try to slide a really thin shim under the front edge of the idler mount and tighten the bolt down to get it level with the spindle pulley and turn it over to see how the belt travels. If that works - I can just grind off an edge of the mount to level it up without having to bend the deck surface.
 

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Discussion Starter · #15 ·
Looking at the parts blow up it looks like the tension spring is not at the right location. The spring is showing attached to bolt or pin 17 in the picture. With the pulley's that close together they need to darn close to bang on.
Well, if that is the case - I will try that first. Wow, is that hard to get hooked on that bolt. I will have to come up with a unique way to doing that. Hard to believe that the belt has to be that tight (it's pretty darn tight the way it is). But, if the belt is too loose - that could explain why the belt isn't traveling correctly around the idler.
 

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spring 42 5.06" long. maybe wrong spring
 

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Discussion Starter · #17 ·

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Get a Spring tool for wresting those things around! Using pliers or a screwdriver is a recipe for trouble: Check this monster: http://www.harborfreight.com/spring-hook-95757.html

As far as the belt goes, there is a way to install it wrong.. Are you routing it correctly? (I've done it too..) Check your owners manual for a picture of the correct route. :dunno:
 

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I have a 54" belt and the spring is mounted to a bolt that is a shoulder bolt. It is not used to secure anything but the spring. Hope this helps.

When working on mine I found it helpful to turn the blades by someone other than myself. That way I was able to look carefully and see what was happening.:fing32:

Gene
 

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Discussion Starter · #20 ·
Well, I'm not feeling very bright tonight. I have worked countless evenings on this issue and spent about $75 on parts I didn't need or that I ruined all to figure out that I should have asked a few more questions before and/or trusted my gut when I put this deck back together.

Tonight I tried the braun over brains method of getting the tension spring stretched far enough to hook it over the bolt. After smashing a finger and bruising my leg in a failed attempt I tried the brains over braun method and got it on there quite easy. The belt still ran low on the idler, so I went to work and leveled the idler to equal the spindle pulley level. Still no good - still ran low in the same place when turning it by hand. In frustration, I decided to install the deck back on the tractor and give it one last try before I called it a night.

What do you know - it ran perfect at any throttle position. Since it was late, I didn't try it under load mowing any grass. So, I guess the extra belt tension is all it needed, the belt still runs low on the idler but does not come off!!!!

Thanks everyone for the ideas and help, it helps a lot to have other opinions. Still can't believe it was that simple. I tried to get it hooked on that bolt several times in the past before deciding that it had to be the wrong place to hook the tension spring as it was just too tight.

Another couple lessons learned today! So that make it a good day after all. :)
 
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