X320 mower belt keeps breaking.

[Pibster]

I have a 2012 X320 mower. The dealer swapped out the 48" deck with a 42" deck from a X300 so that it would fit in our building. It has approximately 500 hours of mowing time. I have gone thru approximately 10 or 11 belts over the years, 4 this year alone. The belt normally breaks when engaging the PTO but not always. This last time it broke while mowing light grass. The belt always snaps, no obvious wear marks. The dealer examined the deck and didn't see anything obvious, they wanted to see the deck attached to the tractor but I only took the deck in to the shop. There was some slight play in a couple of the bearings but nothing that would break a belt. This has been going on since year 2 so bearings are likely not the culprit.
I'm wondering if there is a chance that the X300 deck is not compatible with the X320. They always sell me a belt from the X300. Maybe the drive pulley on the engine is a different size on the larger mower? How much tension should be on the belt? At $75-$85 per belt, this is getting too expensive. Any suggestions would be greatly appreciated.

 

[beenthere]

:welcome: to TBN

they wanted to see the deck attached to the tractor but I only took the deck in to the shop

Get it to them.. They accepted some responsibility when switching decks to accommodate you, so seems you owe it to them and yourself to take the unit back to them to go over it.. obvious that you are not detecting what the problem is, so need their help.

Or the alternative, is to just keep replacing belts, as I see it. Not meant to give you more hard time. Wish you well in the fix.

 

[tomplum]

You are paying a premium price for a M154621 belt. Know your dealer likes to bump the price even more than JD list. OEM Deere belts are physically beefier than the aftermarkets so stick with them. I have had a couple of people that had the same issue. Every time the deck is engaged there is shock load on the belt. If the belt gets caught up into a guide, the torque applied at the clutch will snap the belt. Real excessive forward pitch can get a belt pinched. Think of a belt drive like this as pushing the belt through the maze of pulleys rather than being pulled through by the clutch and you will look at this a different way.
Two things within an operator's control is to engage the deck at 1/2 to 2/3 Throttle and to use the mow in reverse feature rather than keep engaging/ disengaging the deck. AT 500 hours, you do likely need to freshen the bearings and likely at least the vee idler in the back if not all.
One other item on these that can occur is that one adjuster at the rear of the deck runs close to the belt. I've only seen one that actually could hit the belt though.

 

[Amvcane]

Pibster,
At what rpm are you engaging the pto?
If your answer is at full throttle, I would try engaging it over an area where there is no long grass, thus no load, and at a low rpm, and then throttle up to mow.

 

[jgayman]

You are paying a premium price for a M154621 belt. Know your dealer likes to bump the price even more than JD list. OEM Deere belts are physically beefier than the aftermarkets so stick with them.

That's for sure. As you can see below he's charging you around 25% over JD Parts list price. Also note there are two other lower cost belts that can be used.

Part Number: M154621
Part Price: 58.82 USD
On Hand: 7 Check Other Stores
Description: V-Belt - V-BELT
Package Quantity: 1

Alternative Part
A-M154621 V-Belt - JOHN DEERE BELT - 46.14 USD
B1M154621 Belt - BELT - 1/2" X 146.244" KEVL - 52.12 USD

 

[Pibster]

Pibster,
At what rpm are you engaging the pto?
If your answer is at full throttle, I would try engaging it over an area where there is no long grass, thus no load, and at a low rpm, and then throttle up to mow.

I have been engaging the deck at full throttle. It does sometime break while mowing short grass. The end of one of the deck leveling bolts was about a 1/4" from the belt so I cut that off hoping it would fix the problem, apparently not the problem.

 

[Pibster]

My dealer is charging me $80.81 (Cdn) per belt plus tax. Not the Kevlar one either.

 

[tomplum]

The Kevlar label is on the aftermarket belt. The OEM Deere belt may very well be Kevlar if they felt it best. There are several aftermarket options out there. I have 3 that I deal with. The closest in girth was the Stens. The AE I have no experience with.

 

[Diggin It]

I despise the way the belt slaps on my X-300 when I engage it. I've tried at less than half throttle and I get the same thing, but it tries to stall the engine too. I switched to an aftermarket Kevlar belt I get for under $20, but I've snapped a few of them too. Last time a couple of months back, I went through the deck and found a few things that might have been a bit out of alignment and one idler pulley that was noisy. I guess I'll see if that did any good or not.

I don't understand why there isn't a soft start mechanism of some kind to relieve that initial tension.

 

[FortClatsop]

If you haven’t already an inter web search for “X300 belt breaking” brings up lots of stuff on lots of forums and YouTube. I think it’s specific to the X300 and the 42” deck. I remember seeing that when I was looking for info on my X324.

 

[buickanddeere]

I listened in town one day to someone mowing their lawn and re-engaging the mower 37 times at full throttle after they backed up .
I hope thier mower busts into expensive little bits ASAP.

 

[Richard001]

I don't understand why there isn't a soft start mechanism of some kind to relieve that initial tension.

Well I'm sure that it is possible, however I wouldn't wait for JD to come out with one as they make money selling belts as you are keenly aware of.

It would take some work, but I would think that a electronic device could be made to slowly engage the clutch.

Another possible method would be to have a centrifugal clutch that would be activated by the PTO switch.

What would the market place look like for such a device?

Richard

 

[buickanddeere]

Operate engine with just enough rpm to avoid stalling when the mower clutch is engaged.

 

[jgayman]

I listened in town one day to someone mowing their lawn and re-engaging the mower 37 times at full throttle after they backed up .
I hope thier mower busts into expensive little bits ASAP.

My neighbor mows that way. All you hear every few minutes while mowing is SCREEEEECH.... BWWAAAAAA!!! Over and over again.

 

[radios1]

I've been using belts for 45 years, and NEVER experienced, nor heard of a belt snapping clean.. you must be getting cheap knockoff belts from your dealer, try someone else that sells Gates belts.. I've had the same belt on my mower deck on my LA145 for 5 Years, and always engaged it at full throttle, and it's still good.. I think my tractor has a bigger engine than the X320 also.. I also have the 48" deck.. and electric clutch for the PTO.. no squealing.. there's a good belt here, too.. Stens 26599 OEM REPLACEMENT BELT Replaces John Deere M154958 M11313 - Jacks Small Engines

 

[Deere Dude]

My neighbor mows that way. All you hear every few minutes while mowing is SCREEEEECH.... BWWAAAAAA!!! Over and over again.

Make a friend. Tell him all he has to do is pull a switch and hit the reverse pedal and he wouldn't go through that reengaging nonsense.

I had an elderly friend that bought a JD 300 something and he said he was happy with it. I stopped over to his house one day a couple years later and he showed me his tractor knowing I worked at John Deere. He showed me how it cut and I showed him how to not need to reengage the blades by pulling a switch.

I have a X740 and broke one mower belt last year with the tractor at 750 hours. I engage the mower, or my wife does, at full throttle or whatever she happens to be in at the time. I find it hard to believe there is a belt problem with belts on such nice tractors as the OPs.

 

[4570Man]

Most of the times I have a belt break before it’s time it was caused by a sloppy tensioner mount that’s letting the pulley run at a misaligned angle. I also run after market belts. The 160” long belt on my Grasshopper cost about $50 but the shorter belts are less than $20. I paid $12 for the pump drive belt on my Grasshopper. The belts on my Dixie chopper were about $15. Are you letting the belt guards fill up with trash? That’s another leading cause of bent failure IMO.

 

[4570Man]

Well I'm sure that it is possible, however I wouldn't wait for JD to come out with one as they make money selling belts as you are keenly aware of.

It would take some work, but I would think that a electronic device could be made to slowly engage the clutch.

Another possible method would be to have a centrifugal clutch that would be activated by the PTO switch.

What would the market place look like for such a device?

Richard

They had a soft start system many years ago. It was no clutch at all and applying the tensioner to start the blades. That’s how the old G5200 Kubotas worked. If you have an electric clutch applying it at low rpms is the best you can do.

 

[4570Man]

You are paying a premium price for a M154621 belt. Know your dealer likes to bump the price even more than JD list. OEM Deere belts are physically beefier than the aftermarkets so stick with them. I have had a couple of people that had the same issue. Every time the deck is engaged there is shock load on the belt. If the belt gets caught up into a guide, the torque applied at the clutch will snap the belt. Real excessive forward pitch can get a belt pinched. Think of a belt drive like this as pushing the belt through the maze of pulleys rather than being pulled through by the clutch and you will look at this a different way.
Two things within an operator's control is to engage the deck at 1/2 to 2/3 Throttle and to use the mow in reverse feature rather than keep engaging/ disengaging the deck. AT 500 hours, you do likely need to freshen the bearings and likely at least the vee idler in the back if not all.
One other item on these that can occur is that one adjuster at the rear of the deck runs close to the belt. I've only seen one that actually could hit the belt though.

I find the idler mounts wear and allow it to sit angled. I usually use an open end wrench to bend the bracket so it sits right again. That’s by far the easiest way to fix it.

 

[Diggin It]

Most of the times I have a belt break before it’s time it was caused by a sloppy tensioner mount that’s letting the pulley run at a misaligned angle.

I find the idler mounts wear and allow it to sit angled. I usually use an open end wrench to bend the bracket so it sits right again. That’s by far the easiest way to fix it.

I think that may have been part of my problem. One of the idlers sits on an arm mounted at an odd angle and rotates on a bushing. The hole in the arm had wallowed out quite a bit over time and may have been wobbling while in use. I cleaned that out and added a piece of EMT conduit to make it run more true. Hasn't been long enough to know if it worked or not.

The JD fan boys don't understand that green isn't perfect.