How long do the MMM belts last?

[MAXA]

Mine just broke, after 430 hours of course all that is not mowing time but most of it is.

Just wondering if there is another reason that they can fall apart like a bad pulley or something.

Part of the belt is still on the pulley wheels, i was mowing and seen smoke and could smell something burning before hand i assumed it was just grass build up hitting the belt.

 

[Caden]

Yes, with the belt off you need to try to spin all your idlers and spindles by hand. If you have a failing bearing in one of these components then they may start to get hard to turn or lock up.

This could cause your smoke, if the belt is slipping across a seized idler or such. Obviously increasing wear.

That said, I'd be more than satisfied to get 430 hrs out of a mower belt.

 

[MAXA]

Good to know i will check.

 

[John T]

I've got over 800 hours on my 60" MMM belt.
but I grease the spindles regularly and blowout or hose out and grass or crap everytime I cut.

I DO have all my covers removed.... I find it easier to keep an eye on things and keep it clean.

 

[SDT]

Mine just broke, after 430 hours of course all that is not mowing time but most of it is.

Just wondering if there is another reason that they can fall apart like a bad pulley or something.

Part of the belt is still on the pulley wheels, i was mowing and seen smoke and could smell something burning before hand i assumed it was just grass build up hitting the belt.

Obviously, something was wrong causing your belt to fail.

FWIW, after about 20 years, I changed the belt on the 60" MMM on my 1994 B1750 about 10-12 years ago. It did not need replacement at the time but I needed to remove it to replace a failed spindle bearing and replaced it while replacing the spindle bearing. The Kubota replacement is still in good condition after the past 10-12 years.

 

[MAXA]

ok i see the issue the center pulley (the one with the gear box that PTO shaft connects to) wobbles when you turn the pto shaft.

The wheel the belt goes around has a wobble to it.

Any ideas?

 

[John T]

ok i see the issue the center pulley (the one with the gear box that PTO shaft connects to) wobbles when you turn the pto shaft.

The wheel the belt goes around has a wobble to it.

Any ideas?

spindle bearing.

 

[MAXA]

spindle bearing.

How hard is that to replace?

 

[John T]

How hard is that to replace?

never done it on the bota deck but mower spindles are all pretty much the same and basic.

remove the 4 bolts/remove spindle
work on it on a bench.

usually use a hammer and a drift to knock out the old bearings and tap in new ones..

might be seals in there also....

check Messicks for the parts diagram.

pretty easy.

I'd probably do all 3

PS
grease is cheap. use it often.

 

[PoTreeBoy]

ok i see the issue the center pulley (the one with the gear box that PTO shaft connects to) wobbles when you turn the pto shaft.

The wheel the belt goes around has a wobble to it.

Any ideas?

I think you need to determine whether the shaft is wobbling in the gearbox, or the pulley splines are letting it wobble on the shaft. Post you mower model # and I'm sure someone can advise.

 

[RCW]

I've got over 800 hours on my 60" MMM belt.
but I grease the spindles regularly and blowout or hose out and grass or crap everytime I cut.

I DO have all my covers removed.... I find it easier to keep an eye on things and keep it clean.

I’m not that deep, but haven’t changed the belt on my 14 year old BX mower deck.

I grease regularly (reminds me I’m probably due….).

Take deck off each fall to install snowblower. Belt seems fine each year.

Now I’m going to jinx myself…

 

[MAXA]

I think you need to determine whether the shaft is wobbling in the gearbox, or the pulley splines are letting it wobble on the shaft. Post you mower model # and I'm sure someone can advise.

How about a video!

Dropbox

www.dropbox.com

mower is a rck60-30ba

 

[PoTreeBoy]

Access is controlled. Usually it's best to put it on youtube and post a link.

 

[MAXA]

Access is controlled. Usually it's best to put it on youtube and post a link.

I changed it to dropbox, i did take the gear box off the mower deck the pulley that is on the gear box just fell off.

 

[PoTreeBoy]

I changed it to dropbox, i did take the gear box off the mower deck the pulley that is on the gear box just fell off.

OK, dropbox worked. First, I'm far from an expert on these things. But the video sure looks like a bent shaft. I was going to suggest looking at how the blade tracked. But, since you took it off, you should be able to tell for sure. One minor point, in my first post I said the pulley was splined; it's really keyed.

 

[MAXA]

I was going to ask how does the pulley stay on the gear box? There is only a Feather Key that seems to attached to the two.

 

[PoTreeBoy]

I was going to ask how does the pulley stay on the gear box? There is only a Feather Key that seems to attached to the two.

I'm hoping for some help here. The parts diagrams are not clear on how this all stacks up. You should have had to remove a snap ring, maybe two, to get the blade spline boss and pulley support off. Those snap rings are what holds everything in place on the shaft.

Now that you have it off, turn the input and see how much runout the blade shaft has. Maybe another movie? If I interpret the drawings right, you only have one bearing in the gearbox. The lower bearing is in the pulley support which is not in the picture.

In case you don't know, there are parts diagrams at Kubota and Messicks.

 

[MAXA]

There was one snap ring behind the mower blade i had to take off before i could pull it through the mower deck.

I don't see much play on the gear box shaft but once i attach the pulley there is a ton.


Two vids one with and one without the pulley on. Very hard to keep still as the gearbox is to large to fit in my vice.

Dropbox

www.dropbox.com

Dropbox

www.dropbox.com

 

[PoTreeBoy]

I'm going to punt on this one. With it disassembled you've lost part of the support, allowing the shaft to wobble, I think. The pulley is cast, so not likely to be bent, unless that hub is pressed in.

Let's see if we can conjure up @North Idaho Wolfman or @whitetiger .

In the meantime, what condition was the bearing in the pulley support?

 

[MAXA]

The bearing still looks ok, not sure what could be missing the diagram only shows 4 parts.