mower deck belt problem

[digger2]

Please give me a answer to this,if anybody knows.

I've got a 1987 Bolens ST125 hydro riding lawnmower.Your basic rider-
42" deck,recently replaced engine,new blades and loose steering.
Anyway,for a machine as old as it is it works great except for one thing.
I cant find a belt that lasts on the mower deck.It does'nt chew them up or wear them out.What happens is the inside of the belt,the "v" side,starts cracking shortly after i put a new belt on.My last two belts lasted no more than two months.Actually,one only lasted two weeks before it started cracking on the inside and broke.The outside looked like new yet.
I was told by the guy behind the parts counter that i needed a 'HEAVY DUTY" belt if the belt ran on its flat side on any idler pulleys.Well i have three
idler pulleys like that on my deck where it does run around idlers in the shape of a "U". The belt i last used was their "HD" belt,and it did'nt last as long as their regular duty belt.This belt is 158" long and is'nt cheap if i have to keep replacing one every couple of weeks.This mower is'nt used in heavy grass at all.I've never had this problem with a mower belt.Any answers???
digger2

 

[bontai_Joe]

My first thought was your belt supplier stocked up on your size belt in 1982 and they are cracking from age. But then I got to thinking you didn't mention where you are getting these belts. autoparts store? Tractor Supply Co? Some belts are not manufactured to run on small diameter pulleys as well as others. But I'm not sure where to get genuine replacement part belts as the original manufacturer of your tractor doesn't exist any more... maybe MTD has them?

 

[Eagleview]

I'm assuming the belt is running around the pullies in the correct sequence . It may be worth trying a cogged belt as they are less prone to cracking going around tight radius pullies . Gates or Dayco would be my choice .

 

[alchemysa]

The belt i last used was their "HD" belt,and it did'nt last as long as their regular duty belt.T

Was the belt fabric covered or just plain black rubber?

There are a heavy duty belts made for mowers. The ones I have used are totally encased in green or blue fabric. The fabric is to allow a degree of slippage but I guess it would provide extra strength for a belt that bends 'backwards' around the pulleys (as many mowers do.).

 

[digger2]

I'm getting the belts from a good size lawn tractor dealer-they sell everything from Grasshoppers to Echo weedeaters.
The belt is running correct as theres a diagram sticker still on the deck.
Also,the belts are Gates.They are black but not just plain rubber.They have a canvas covering all around.The last one i got was called a Green Stripe 2.
I know what you are talking about as far as the green belts.My dealer says they cant get this belt in that size(??????).
Somebody told me today that TSC carrys belts for garden tractors made with Kevlar.I'll have to check it out......
digger2

 

[alchemysa]

My dealer says they cant get this belt in that size(??????).

Not that I'd really know, but yes that does sound like a big belt for a ride-on.

I get my belts from a specialist belt/hose shop. Most cities will have one.
They are quite a bit cheaper than the local mower shop.

 

[shot_gun]

Have you checked your v pulleys for wear? It has been 21 years they might not be "v"'s any more. Also idferent belts have diferent pitch to the v and you may not be getting proper contact between the belt and pulley causing the belt to get pinched in the inner portion of the pulley. Just a thought.

 

[dqdave1]

I agree; check pulley pitch; may be getting wrong pitch belt. Might be easier to get pulleys.

 

[studor]

If you have the dimensions of the original belt you can usually get a kevlar replacement at a farm machinery dealer I have a craftsman that did not seem to like to keep belts after mowing a few rocks The deck belt seemed to me to be pretty expensive so when I was getting parts for something else at a farm equipment outfit I asked about belts and blades -- no problem much cheaper and they suggested kevlar (also cheaper than Sears) I have not broken or damaged the belt in over two seasons (and I still mow rocks occasionally
Ps --make sure those pulleys actually turn and the tensioner is functional - sounds like the belt is taking abuse from some part of the setup

 

[zzvyb6]

Cracks as you describe imply that the belt is seeing more curvature than it was designed for. Look for an idler pulley that's too small. This might mean you need to change the belt length as a result. If the deck is not the original, check to see if the pulley width and v-groove is the same as the driving pulley groove. On my Simplicity, the deck pulley was 3/4 and the clutch pulley was 5/8". Somebody added a 48" deck to a system that came with a 42" deck. Oops....

 

[digger2]

I'm not sure guys,but i think i got it.Turns out the belt was making contact with the idler pulley arm.Not alot,just enough to make slight contact and cause some wear.(wish i had a digital camera,it would be alot easier to show than explain).Yeah i know,DUH.You could'nt see it until i did some serious disassembly work.
Also,its possible i had the belt too tight,thus explaining the cracking.Even though i have the original owners manual for this thing,nowhere does it say anything about belt adjustment.(Strange)So me being the kind of guy i am,if snug is good ,tight must be better,right????No,wrong!!!!!! Another DUH.
Anyway i notched the idler pulley arm just enough so the belt would'nt make contact with it and installed a new belt(GATES POWER RATED)and tightened it up just enough so it would'nt slip.So far so good.I inspected it after the first mowing(3.25 acres) and no cracks yet.
The only thing i can say is somebody must have modified a pulley size or something before i bought it as it did have the right size belt on it.(i bought the mower used)And the owners manual absolutely says nothing about belt adjustment.Thats some of the trouble with buying something used.You never know what the last guy(or guys) have changed or modified.Anyway i'm keepin my fingers crossed
that this is the last belt for awhile.............thanks for the advice,digger2

 

[Tim12659]

Pulleys can sometimes cause this ...a badly worn pulley, a "BURR" protrudung from a pulley will cause cutting or if the bearings are worn and causing the pulley to wobble or be out of alignment so bad it will cause this.
As far as belts...find a Auto Parts store that carries GATES Belts. Take your old belt so to get the proper length and tell the people you need the heavy belt. You'll find that the Gates belt will outlast, out perform any OEM Belt on the market.