1864 / 54GT deck throwing belt

[amanfrromthere]

1864 w/ 54GT deck

I was mowing the other night and the deck belt came off. Flat ground, no obstacles, no obvious reason why it would. Has never happened before. I pulled the belt off and did find a tear in it, so I figured it was just the belt since I had no clue how old it was.

So I bought a new belt (954-3045) and threw it on. As soon as I flipped the PTO on it threw the belt off. Didn't even get up to speed. Pulled the belt and compared it to the original, same size. When it happened the second time, it also tore the belt the exact same way as the original, so I'm guessing the first one was not caused by a damaged belt, rather the belt was torn when thrown off.

Having already wasted money on one replacement, I'd like to make sure I have all my bases covered before I try again. I'm going to pull the deck tonight for a closer look.

Things I should check/do:

- Balance / Level deck
- Check that mule drive belt is in plane with spindle pulley
- Check for spindle movement
- Check if spindles are in plane with each other

What else should I look at?

The idler arm assembly seems ok, but I don't really have a reference on how it should feel. Is there any adjustment on those? I can pull the one off my parts deck and try it. Can't imagine it's in any better shape than this one, but if it makes any noticeable difference then I'll just order a replacement.



Thanks

[Mike McKown]

I've had it happen several times on 48"-54" decks. In all known cases, it was a chunk of wood stuck in the pulley groove.

In one case, I had a 48" deck out of loan that started throwing the belt. I supplied another deck and haven't looked at it yet. The user said he couldn't see anything wrong.

[Hairtrigger]

Check all pulleys for vertical movement

[R Bedell]

Check all Pulleys, Idlers, and Spindles to see if they spin free.

[amanfrromthere]

Everything spins freely. Tiny bit of side to side play in the spindles, equal amount on all three. Doesn't seem like it'd be near enough to make the belt jump like that, but I'll see if I can tighten them up any.

The tensioner on my parts deck seems a lot stiffer, quite noticeable (even if it is a little rusted). The nut wouldn't budge even with an impact though, the bolt is worn down to a nub and it all just looks fused together. May as well just replace the whole assembly.

[bugeye]

I recently destroyed a bearing spindle on my 54" deck. Hit a stump and broke the bearing housing. All fixed with used and new parts.

Is it possible you hit something and cracked the spindle housing? Is a shaft/pulley deflecting under operational load? Is a pulley deflecting on the shaft?

[amanfrromthere]

Originally Posted by bugeye

I recently destroyed a bearing spindle on my 54" deck. Hit a stump and broke the bearing housing. All fixed with used and new parts.

Is it possible you hit something and cracked the spindle housing? Is a shaft/pulley deflecting under operational load? Is a pulley deflecting on the shaft?

Haven't hit anything recently that even gave the mower pause, so that seems unlikely. I'm gonna power-wash the whole thing this weekend, so that'll let me look for potential cracks.

[ol'George]

Originally Posted by amanfrromthere

Haven't hit anything recently that even gave the mower pause, so that seems unlikely. I'm gonna power-wash the whole thing this weekend, so that'll let me look for potential cracks.

Power washing makes everything nice and squeaky clean it also makes bearings squeaky, and anything else that turns or moves.
Check your idler pulley and especially the pivot and tension spring.

[amanfrromthere]

I replaced the tension spring and shoulder bolt. Belt was noticeably tighter. But, it threw the belt even faster on first go. I think the new spring exacerbated the issue.

It slips off the idle pulley. I can make it slip off just turning it by hand. The pulley has some play and with the new spring is noticeably tilted. But it’s also a bit higher than the spindle pulley next to it. The shoulder bolt is torqued down pretty well. Not sure how much torque that bolt should actually get, is it specified anywhere?

Pics/vids

https://photos.app.goo.gl/rTxUjdkVn6WH6RaK6

[R Bedell]

Looks like one of the Spindle pulleys is angled and out of alignment.