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Rotor Belts on a 1680

6751 Views 12 Replies 9 Participants Last post by  redfan55
I have a 1990 1680 and my rotor belt went out on the machine this summer. It was on the machine when I bought it and had ran 2 years before it went out. In quick succession (less than a 150 acres of wheat) I went through 3 more belts. We finally put bearings and everything in the hub and it seemed to run okay after that. The spring was replaced also. I finished wheat (250 acres) and have cut about a 100 acres of milo and the rotor belt is gone again. The dealer has checked the alignment and everything else that we can think of. Is there a possibility the belts are bad or is there something else I need to check. Another customer has had issues with their rotor belts also. I bought a gates belt to put on this time. I am tired of spending $300 + for a belt each time one goes out and I sure don't need the experience of putting another one on!
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You should check the bushings in the driven sheive it should be nice and tight side to side but turn on the shaft easily as it has to turn back and forth for the cam to be able to tighten the belt as it is working the heavier spring only puts a partial tightening on the belt . Also there is a small radial bearing under the spring that allows the spring to turn as the speed changes which tends to get rusted up and won't turn easily this all helps out the torque sensing of the pulleys work , as the rotor needs more torque the driven pulley will tighten itself up on the belt through the cam assembly . they should all move easily and not bind anywhere .
I have done all that you indicate I need to check. The first belt ran about a hundred acres, the second belt ran about the length of a city block, the third belt lasted about 40 acres and the fourth belt lasted about 350 acres. As I said we put the cam bearings in, the thrust bearing under the spring, we check alignment, and the dealer has checked the sheives.
Sounds like you got into a crappy batch of belts . Hope your dealer will help you out . Try another dealer ?
Are you tensioning the new belts as per the manual ?? Had a friend with similar trouble, turned out he was running the belt to loose and it was prematurely failing because of being too loose. Just a thought jeff
have you checked all the vanes in your rotor cage. if they are folded over your rotor belts wont last very long.
ya try a different dealer because i shop at one dealer and on a trip somewhere i stop and get one and they always seemed to work
Some good posts there to check never thought about cage vaves also on belt tightening don't use that stupid guage as it allways gets screwed up when a belt blows there is a good section in the owners manual about setting the limit switches and belt tension using a (i think) 5/8 guage i had milled one down from bar stock and it was easy to use .
Be sure the ramps of the cam are flat with no worn pockets. My 1480 did this and the torque sensor would hang up in the pockets and the belt burnt off. Just a thougth

There is also an updated spring and ramp for the torque sensing pulley that has quite a bit more clamping force to it. I beleive it was changed sometime in the 2300 series, but not exactally sure when. The part numbers may even sub up. Everyone else that has posted have very good points. Bushings, rollers and ramps that are worn won't allow the pulley to keep proper tension on the belt. Items in the rotor, cage area that are worn will cause ecessive power draw and put more strain on the rotor drive. I also should mention that I worked on a couple machines that were getting too much grease and there was grease packed and caked around in the torque sensing pulley not allowing it to operate properly, but I'm assuming that since you have been working on it, you probably would have noticed that by now.
Very basic thought, a moly grease should not be used in the rotor toque sensing unit only a lithium base product. The moly grease will not allow the sheaves to slid properly.
Really redfan?
Never heard that before, wonder if affects all drives?
Or just with IH?
Guess what grease I use?

Yes, been around these things since '78 worked for dealer til 01 now on my own, struggle at times. Were always told at schools and see even on pre-delivery sheet of aleast 04 combines use only CIH 251HEP on torque sensing unit. Have alot of customers with seperate grease gun just up there for that reason. Moly is good on everything else.
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