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I have a 2003 Troy-Bilt Bronco J609. I am on my second drive belt so far this season.

Now when I first start it the belt slips off the idler pulleys, when I go to put it back on I see that the belt has flipped (rotated 90 degrees) on the engine pulley. I remove the engine pulley and put the belt on correctly and check to see that it follows the correct route. The next time I start it the process starts again. I can't figure a way to un-twist the belt without removing the engine pulley, I have no idea how it can twist. There are scores on the outside surface of the belt, don't know where those came from and if it is related to the twisting. The belt is looking worn and stretched.

Any help would be appreciated!!

WELCOME to LMF

The belt may be damaged to the point that it will need to be replaced..
The cause of this is most likely pulley misalignment or a bad bearing on one of them.... check them out and if there is a problem,repair the cause before replacing the belt... :smile:KennyV

I had the same problem on my 05 Bronco. The drive belt would fall off every 15 minutes or when I hit a bump. I called for service under warranty. They put a L-shaped guard bracket on the tension pulley to prevent the belt from slipping out, and the problem went away. Attached picture shows the pulley and the bracket installed.

Interesting, how do you replace the belt with the bracket in place?

lhoo said:

Interesting, how do you replace the belt with the bracket in place?

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You disconnect the spring, then loosen the bolt. The belt should be able to squeeze out. You have to remove the battery to give you enough work space. The belt doesn't wear out that often. I only changed it once, in 08 or 09.

I had the same problem on my 05 Bronco. The drive belt would fall off every 15 minutes or when I hit a bump. I called for service under warranty. They put a L-shaped guard bracket on the tension pulley to prevent the belt from slipping out, and the problem went away. Attached picture shows the pulley and the bracket installed.

Click to expand...

Maybe I should ask for clarification -- did the belt just slip off or did it also flip? Also, my belt is flipping on the front engine sprocket, it is slipping out of the idler pulleys, haven't had problems with the back pulleys.

lhoo said:

Maybe I should ask for clarification -- did the belt just slip off or did it also flip? Also, my belt is flipping on the front engine sprocket, it is slipping out of the idler pulleys, haven't had problems with the back pulleys.

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In my case, the belt just slipped off, never noticed any flip. This is the CVT belt almost directly under the seat.
Are we talking about the same pulley or are you talking about the engine pulley on the engine spindle? There is also a bracket on both sides of the engine pulley. The bracket should prevent the belt from flipping or slipping off. I never had problem with that belt.

Are we talking about the same pulley or are you talking about the engine pulley on the engine spindle? There is also a bracket on both sides of the engine pulley. The bracket should prevent the belt from flipping or slipping off.

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The belt is twisting (flat side towards pulley) on the engine pulley. Yes there are two guides that would seem to prevent the belt from twisting. I have tried to untwist the belt without removing the engine pulley, it is not possible. I can't figure out how it can twist in the first place.

lhoo said:

... I have tried to untwist the belt without removing the engine pulley, it is not possible. I can't figure out how it can twist in the first place.

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If a pulley is bent or out of round, the belt has a broken cord in it or is in any way damaged, If the pulleys are out of alignment or a bearing is rough.... the belt will start bouncing in the open spans between the pulleys, when they bounce at the proper rate they can actually grab better on one side of the pulley... that is what causes them to flip or twist...
The point that starts the twist can easily be damaged and may continue to twist, even after the original problem is corrected... :smile:KennyV

the belt has a broken cord in it or is in any way damaged

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The belt is most certainly damaged, cord hanging out here and there and has heavy scores on the back (flat) side of the belt. I hate to replace it again with a new (and expensive) belt, only to have it ripped up. All the other idlers and pulleys look fine, but it is almost impossible to see much without flipping the mover over

I had a craftsman mower that had a bad ideler pulley it was going bad on top where I could not see it it was also plastic sears finaly gave a metal replacement pulley ran fine since. check your idler pulleys they are not expensive to replace check your belt guides and make sure everything lines up. look on you tube or google there might be a video showing what to look for