2003 jd l120 48in 2015 husquvarna 54 inch

pcman888

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Hi this is mike i have a jd l120 48 inch that wouldn't keep the blade belt on.may be fixed now i put the big idler pulley on the deck it looks bigger and taller hope it works.
 

bertsmobile1

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For belts to stay on a mower where the belt run is not in a single plane all of the pulley spindles must be parallel to each other.
Usually the tensioning arm wears and allows the tension idler to tilt
Once the tilt gets too much nothing will keep the belt on.
People rarely lubricate the pivot on the tensioning arm.
SO the hole flogs out oval then the arm itself can twist and the twisting action wears a groove in the underside of the arm which allows more tilt in the pulley spindle .
This is a self energizing set up.

I weld about 30 or so tensioning arms up every season, making the hole round again and the bottom flat again so it can only swing in an arc which is true to the axis of the pivot bolt.
On those JD decks the spindle housings are quite strong so rather than breaking like the Husquvarna ones do , shock loads tend to twist the deck pressings so the pulleys on the spindles are no longer co-plainer .
Of all the mower I repair, the JD decks require the most 10lb hammer rectification.
 

pcman888

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i replaced everthing that was bad or worn ,i missed the big idler cause it 's bearing was okay.i spun it the other day and it was warped.be a week before rain quits before i can try it. thanks
 

bertsmobile1

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i replaced everthing that was bad or worn ,i missed the big idler cause it 's bearing was okay.i spun it the other day and it was warped.be a week before rain quits before i can try it. thanks

Including the idler arm, and bush ?
 

pcman888

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yes i done it first with a new upgraded idlerarm the wheel and the bushing,a new jd belt flew off still.ireplaced all 3 spindle bearing and the spring and that helped it stayed on but still rode up on the big wheel then i seen it was warped.the belt was riding up and wearing the edge and getting hot.
 

bertsmobile1

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I will suggest that the deck is slightly bent at the pivot point so the pulley is slightly skewed.
Stand back a bit and eyeball the pulley to see if it is in the same plane as all the others
It does not take much of a twist to make the belt run off.
 

pcman888

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ok thanks i didn't think of that since it's 16 years old it could be,i will look in a little while and see.the new pulley really looks good though and seems a litte taller i will look and turn it both, thanks alot i have lost 2 belts and this one has been damaged.
 

Catherine

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:welcome:

Welcome to the forum!

I'm going to move this thread over to our John Deere section.
 

pcman888

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ok thanks this was my intro post i guess i should have put it somewhere else.
 
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