PTO belt will not stay on

[RLW_LT2138]

I’m having a problem keeping the PTO belt on my 2004 Cub Cadet LT2138 lawn tractor. Sometimes it works for an engagement or two and then jumps off the pullies. I had a similar problem several years go and it ended up being a bad spindle and went away after I replaced the bad part.

I have to sharpen the blades after each weeks mowing and I grease the spindles each time. The seem to move freely. A couple of weeks ago when it kept coming off, I replaced the belt with a new OEM belt. It seemed to fix the problem even though the “old” belt was not very old. The current belt is slightly looser than it was the first time I put it on, it seems fairly tight and has less than ten hours run time on it.

Does it make sense that the tension spring on might have lost some of its strength over the years and is not keeping the belt tight enough? I’m looking at ordering a new spring, but thought I would run the idea past this group first.

Thanks,
Rich

 

[StarTech]

Check the double puley bearings for play. I just had that ran his CC until the pulley was destroyed because he didn;t pay attention the bearing noise. This pulley is over $100 but both bearings are easily repaced before things gets too bad. The bearings are common 6203-2RS5/8 bearing with the inner seal removed. so you can grease them via the pulley's zerk. No needto pay over $25 each for the CC bearings.

Also check the idler pulley and the idler arm itself excessive play. There is also a pair of idler pulleys on the front of the mower but I have yet to see one of them with bad bearings. Always a possible though.

 

[RLW_LT2138]

Thanks, I will check those spots before I order the spring.

 

[bertsmobile1]

Go to a Cub dealer and look at where the belt sits in the spindle pulleys
Then look at your own pulleys
You will see yours have worn and the belt now sits a lot deeper and feels looser.
So while the spring will have lost a little tension, that will have no where near as much effect as worn pulleys
And the idlers wear grooves as well thus reducing their effective diameters.
Usually I fit a slightly larger flat idler to take up the wear on all the other pulleys & restore the original tension in the belt if the V pulleys have a reasonable amount of life left in them.
Then again my game is to get the customers mowing best as I can for least cost.
The Cub dealer would simple replace the entire pulley set if he was good or the entire pulley & spindle set if he was a rouge

 

[RLW_LT2138]

Thank you for the suggestions.

StarTech - I removed the spindle belt from the double pully and checked it. It turns freely and the bearings do not seem to have any play. I also checked the two pullies by the front wheels. they turn freely. The spindles also turn freely.

Bertsmobile1 - The belt I'm having trouble with is the one from the PTO to the deck not the spindle belt, It does not have any idler pully. If my problem is worn pullies it would be the double pully, the two by the front wheels or the PTO itself.

I'm going to start the cheapest part which is the $20 spring. I'll update this thread with what happens, so it can be useful if someone else has this problem.,
Rich

 

[RLW_LT2138]

I said I would post what I found, so anyone else with this problem could use my experience as guide.

I ordered and installed the new tensioning spring, as the others expected it did nothing. It was tighter than the old spring, but did not solve my problem.
I checked all the bearings etc. and did not find anything worn.
I then carefully cleaned and re-greased the mower blade shafts. This seems to have solved my problem. I had been greasing them at each blade sharping, but I guess they needed cleaned and repacked.

Thanks for all the suggestions and I hope my solution will help someone else.