Repairs MTD Belt Failure

[Steve Smith]

I have a Cub Cadet Model 2186 built by MTD. I have been experiencing pre-mature belt failure of the PTO belt that drives the mower deck. I have been using genuine MTD belts. I have lost 4 if them already this summer. The off-brand belts seem to last longer, but they still fail after about 6 to 10 hours of mowing. I thought my pulleys might be warn. So I replaced the PTO clutch and pulley and the double pulley on the deck. Checked the alignment. Still having failures. At this point, I am thinking that the MTD belts are defective, but am not sure.

 

[platefire]

Hi Steve

I have no experience with a Cub Cadet. So I'll get that out of the way from git go. You checked the alignment and so it seemed ok. What about the tightness of the belt when engaged. Does it feel super tight when engaged and is there a way to adjust tension---or is it controlled by the spring tension on the idler pulley?

If it's in alignment, the belt tension is not overbearing, then maybe check for burrs or deformities on the pulleys. Something is not right for you to go through that many belts! So you might have to inspect extra hard to find it. Platefire

 

[ILENGINE]

What the damage on the belt looks like can give a clue what the issue is. A picture of the damaged belt can help us narrow down the problem.

 

[mechanic mark]

https://www.cubcadetpartsnmore.com/cub-cadet-service-manuals

see pages 152-157 good information, just click on 2000 series 2011 & after service manual.

 

[Steve Smith]

What the damage on the belt looks like can give a clue what the issue is. A picture of the damaged belt can help us narrow down the problem.

I believe that I have thrown all the damaged belts away. If I can find one I will take a picture. The Kevlar jacket comes off. I assume the adhesive is not able to take the temperature from the friction. The belt is very warm. I am not sure if that is normal. The tension seems high to me. It is a spring loaded tension pulley, but the tension seems a lot.

 

[bertsmobile1]

Sound like you have the belt on the wrong side of one of the belt keepers.
That is exactly what happens the covers rip off & the belt shreds in no time flat.
And we have all done it at least once before

 

[Steve Smith]

I found one damaged belt in my trash barrel. It is not an MTD belt but another one that I had tried. This one lasted 6.4 hours before it died. The MTD belts have been lasting about 2 hours before they self destruct. They all look similar with the outer covering coming off. I do know that this belt gets very hot, it always has, but 2 years ago I was getting at least a season of service out of them.

 

[bertsmobile1]

Firstly belts get hot in use, in fact they get very hot
Flip the bonnet on your car after a drive and feel just how hot the fan belts get.
Like all rubber products, when they get hot they get sticky which is good for a fan belt or lathe drive belt but not real good on a mower when you need the belt to slip which is why they are covered.
Did that belt actually break or just start to slip
If it broke a photo of the fractured ends would be good, side on and end on.
I see the back is rubbing but only on one edge.
This happens when there is a bad twist on the belt or the back is running on a V pulley or belt keeper.
On that set up the back of the belt should not have a mark on it as the tension is applied by the lever on the deck.
It should go into the V on the PTO pulley then the V of both of the front idlers so the bet has a 1/2 twist on it the the the deck pulley with a second 1/2 twist.
Thus only the V face ever touches a pulley so there should be absolutely no wear on the back of the PTO belt on any 2000 series Cub

Next is that a 5/8" ( B section ) belt ?
Looks like it has an A ( 1/2") size on it.
If so it will run way too deep in the pulleys.
Your belt should be a B 112.4

 

[ILENGINE]

Belt is rubbing something. May not even be on the deck. Could be something on the belly of the tractor frame. Something bent, something worn and the belt in its normal vibration flop could be making contact with something in close proximity So will need to look at everything that is close to the belt for shiny rub spots.

 

[bertsmobile1]

Had a few minutes to think about it, while feeding the shed cat.
Are you putting the 1/2 twist in each side of the belt so the V is pointing down when running through the 2 V idlers on the front ?
Belts can flex V in or V out without problems but flexing sideways is very bad so if they are running side on through the V idlers you will wreck them in no time flat.
After that the deck lock lever would be my next guess.
They get mangled up and when bent out of shape can foul the PTO belt
It should run under the handle not over.