Deck belt getting loose

jw11432 · #1 06-12-2017, 11:43 AM

This is a 2135 as best as I can tell (bought used, was repainted so no markings anywhere). I've recently run into the problem where my mower want cutting grass and producing a lot of smoke, which turned out to be a stuck deck belt. I replaced it, and despite it seeming like a good fit, it has loosened up considerably at one mow and even then would not cut unless I went very slow, it seems the grass was preventing it from cutting. Manuals indicate it should be using a 59" belt, but a 57" fit much better. Initially tried a 56", per the inspection of old belt by store employee (no numbers left on it, based on sizing and suspected stretching amount).

I've managed to figure out that the deck belt and PTO belt must be the perfect size, or else one will be too loose. Do I actually need a 56" belt, and is there a common practice of pre stretching these a bit to help counter this problem? Otherwise, any ideas as to what I might inspect? Tensioner and spring seem fine, but I have no real basis of comparison either. Appreciate all feedback!

sir_lancealot · #2 06-12-2017, 12:20 PM

Can you find the ID Plate and give us the model number listed there? We'd all know for sure what model it is that way.

You only mentioned one size of the belt....there are 2 you must follow. You need a 1/2" x 59" belt. If you got a smaller width belt, it might not be holding properly. Also check and make sure every individual item turns freely with the belt removed, then try again once the belt is on. Make sure your PTO belt is proper and all pulleys are spinning freely for that one too. Looks like that one should be 5/8" x 112.25".

Terry C · #3 06-12-2017, 01:17 PM

Make sure the lever that tightens the belts is working properly. It affects the drive and the deck. Make sure it's free of debris and is lubed.

jw11432 · #4 06-12-2017, 04:20 PM

Apologies, yes it is 1/2" by 57" currently in place. I did find where it's supposed to be a 59 but given how loose a 57 has become a 59 is a sure bet to be too big. Where would I find a plate for identification? I have searched everywhere but can find nothing on the machine in the way of identifying marks.

The lever is in fact tight and appears to be fine. Again with no basis of comparison it's subjective to say but I'm very mechanically inclined, knowing my way around cars for about 15 years now.

sir_lancealot · #5 06-12-2017, 04:32 PM

I THINK it would be along the left frame rail somewhere. Might have to remove the engine side panels to find it. If not, it probably got painted over as they were just stickers, not a stamped plate.

If the belt is too tight, it could be causing issues as well. Maybe try the size CC calls for and see if anything changes? Worst case, you have to return it cause it didn't work.

jw11432 · #6 06-12-2017, 09:03 PM

Now that I'm at my keyboard and not my phone, I'll see if I can better explain the situation.

The manual I found for the 2135 indicates a 1/2" x 59" belt. When I compared it to my old belt, it was a bit bigger than my old belt, which presumably had stretched. So I tried the 57" and at first, it seemed to have a pretty good fit on the pulleys. Despite this, I would have to slow way down for it to actually cut (where as before I could go at a pretty brisk pace and it would cut beautifully) indicating to me that the blade pulleys were not being turned. I could also hear a difference in the mower when it was cutting and when it wasn't. So I have two questions:

1) Is there an accepted practice of pre-stretching these belts a bit? I think the 56" is what I need, but it would be very tight so a little pre-stretching seems to be the way to fix it, especially considering how much stretch the 57" got after 45 mins of mowing.

2) Could a bad PTO clutch/unit be an issue here? Further clarification of my thinking: when it hits grass, it doesn't cut well. As opposed to a slipping belt, could it be a PTO clutch on its way out, as in not enough power to keep the blades moving? Looks like they're only about $120 on ebay, so that's not going to be devastating news. I also noticed what appears to be grease zercs (sp?) on the blade pulleys, which I didn't realize were there at first. I don't know what kind of maintenance this mower got prior to my acquisition, but they appear to move freely without a belt on them, so I don't suspect that to be an issue. Perhaps a new idler pulley and spring is in order, they do seem a little wonky.

Thanks in advance, I'm trying to be thorough, but those 2 questions are the most pertinent I can think of. I'll see if I can find any identifying marks/numbers or anything, but I looked it over pretty good already so I'm not hopeful.

Terry C · #7 06-12-2017, 11:04 PM

How does the spindles turn by hand with just the deck belt on? If it turns fine then put the drive belt on and see how it turns. If still ok then I would guess some PTO clutch problems.

sir_lancealot · #8 06-13-2017, 11:06 AM

This is more outside my wheelhouse as nothing I own uses an electric clutch. Hopefully someone will come along soon and give you more insight on that. If everything turns freely and doesn't appear to be binding, you could have a PTO issue.

As for the belts...I do know a good quality belt won't have much stretch to it. Only cheap belts stretch to the extent you're referring to. Keep that in mind if you find yourself going through a lot of "cheap" belts.

jw11432 · #9 06-13-2017, 03:43 PM

Well, admittedly I did opt for the $15 belt as opposed to the $50+ Cub cadet brand. As for the turning test, I would think the drive belt should turn freely even in a normally functioning PTO. My logic here is based on it being an electric clutch, so without the electromagnet engaged, shouldn't it turn freely by design? I'm sure there's a test I can do if I find a good manual, but I may just replace the stupid thing for good measure. I'll update this thread when I get things figured out for future reference for others.

ol'George · #10 06-13-2017, 04:36 PM

Quote:

Originally Posted by jw11432

Well, admittedly I did opt for the $15 belt as opposed to the $50+ Cub cadet brand. As for the turning test, I would think the drive belt should turn freely even in a normally functioning PTO. My logic here is based on it being an electric clutch, so without the electromagnet engaged, shouldn't it turn freely by design? I'm sure there's a test I can do if I find a good manual, but I may just replace the stupid thing for good measure. I'll update this thread when I get things figured out for future reference for others.

A lot of electric clutches when not powered, are in a brake position.
Because the gubber mint has a standard that says they have to come to a stop in a said amount of time after disengaging.
So it might turn, but with difficulty, because of the brake feature.