X300 breaking belts

[JHouston57]

Greetings all,

I bought a new X300 from a local JD dealership just before the 2015 mowing season. I mow appx 1.5 acres weekly with an additional .75 acres about every two to three weeks during the season.

Love the mower, I have it serviced "front to back" at the end of each season and it worked perfectly during the 2015, 2016, 2017 and 2018 seasons. At the beginning of the 2019 season, the large deck or blade belt broke after about two weeks of mowing. The belt was replaced and I was able to mow about four weeks when the second belt broke. I have now mowed about 8 - 10 weeks and the third belt broke today!

Has anyone else had this problem? Any suggestions? I just can't understand how the mower has worked perfectly for 4 seasons and now I have experienced 3 broken belts in one season..

Any help or suggestions are appreciated.

JHouston

 

[tom3]

Actual John Deere belts?

 

[bertsmobile1]

Belts, pulley & blades are all wear items
One of them needs work
We need to see the broken belt, in close up at the break.
The type of failure will go a long way to determining the cause of the failure.
Just about every belt maker & mower company puts out a belt failure chart / book

 

[gotomow]

Belts, pulley & blades are all wear items
One of them needs work
We need to see the broken belt, in close up at the break.
The type of failure will go a long way to determining the cause of the failure.
Just about every belt maker & mower company puts out a belt failure chart / book

Spot on. Maybe this video will help: https://www.youtube.com/watch?v=-Df992NOIzU

 

[JHouston57]

Spot on. Maybe this video will help: https://www.youtube.com/watch?v=-Df992NOIzU

Extremely helpful.

I failed to say that the service company replaced one of the pulleys and put new blades on the mower at the end of 2018. It is beginning to look like a pulley and alignment issue.

 

[Deleted member 97405]

Extremely helpful.

I failed to say that the service company replaced one of the pulleys and put new blades on the mower at the end of 2018. It is beginning to look like a pulley and alignment issue.

These decks were notorious for breaking belts. Deere actually put out some bulletins about it. There were several things that could cause it. The main 5 issues I found are:
1. The pivot bushing and tension arm have worn and are sloppy.
2. Depending on your serial number and year of manufacture, the belt could contact the right side adjuster bolt, which will tear the belt. This was fixed on the later models when Deere welded the lift bracket in a different place. If you look at the bolt, you will be able to tell if the belt is rubbing it. Just cut off some of the bolt to provide clearance.
3. I had one where a customer hit a root on the curved piece in the rear center of the deck underneath. If you look under your deck, this the curved piece that is welded to the underside of the deck. This pulled the center of the deck shell down and pitched the main pivot shaft forward, which misaligned all his pullies and kept breaking belts. Even after doing everything listed here, he still was breaking belts. We tried to straighten the deck shell, but it kept returning to the bent position. Only fix was to replace the deck shell.
4. Check your stationery idler pulley mount on the rear of the deck. Remove the pulley and make sure the welded mount isn't twisted. Some of these mounts will twist forward and pitch the pulley at too much of an angle. The fix is to straighten it as best you can with a hammer and add a large washer to give the pulley a more stable surface to sit on.
5. Lastly, your PTO clutch can engage too aggressively. When the clutch plates wear, they can engage too aggressively and 'snap' the belt. The clutch is supposed to slip a bit as it engages. I have replaced several clutches that were still working, but snapping the belt too quickly when engaging.

Most of the time, the issue is a combination of any of the above.

Hope some of this helps! I have worked at a dealership since 1998. These decks are great when they work, but pain in the butt when they start eating belts.
Good luck!

 

[deckeda]

-Will

Deere tech with over 21 years experience. I don't know everything, but am here to share my knowledge, help people help themselves, and learn new things!

Should have said this earlier but I think it's pretty awesome you're here.

 

[Deleted member 97405]

Should have said this earlier but I think it's pretty awesome you're here.

Thanks! I recently moved up to a sales position here at the dealership, and helping folks on here has become my hobby during my break times.
Plus you're never too old to help others or to learn from others!

 

[NorthBama]

Thanks! I recently moved up to a sales position here at the dealership, and helping folks on here has become my hobby during my break times.
Plus you're never too old to help others or to learn from others!

Thank you for sharing your knowledge. I enjoy reading your post.

 

[jackislost1]

I have this same problem with my x300, and have discovered that the j-hook on the right side of mowing deck is clipping the belt every now and then. I am in the process of replacing all the top side of the mowing deck and then some things associated with the lift pedal linkage. I think I got my lift arms back in line but won't know for sure until the rest of the parts come in mid next week. Will put them on and then see how it mows. Hopefully will be back in business. For the life of me I can't figure out where the extension spring that is associate with the lift lever, where it connects on either side. . If the attachment worked it would be #18 on the sheet. Can anybody shed some light on this please??? Thanks