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Discussion Starter · #1 ·
Have many of you had issues with the countershaft on these machines? We've shelled 850 ac of corn and no beans with this machine this year. It's an 09 with 1100 sep hours.

We parked it 5 days ago with no known issues, got 5 inches of rain and just got fired back up today. I noticed a bad vibration when not under a load and could see a lot of movement on the right hand side of the countershaft where the cylinder variable speed pulley is. We got everything apart and can't see anything wrong with the bearings and when we run it the shaft is definitely wobbling on the right side.

My question, what could cause this. Haven't slugged it this year or had any problems. Im fairly certain it wasn't vibrating last week because it was bad and very noticeable today. We don't have the shaft out yet but I wonder if it's not cracked and causing it to bend because I know if seen other people break the shaft. It just doesn't seem like it should happen now, I wouldn't be suprised if we had been cutting a bunch of green stemmed beans. Thanks
 

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If it is bent do not run it. Ours broke just outside the bearing holder on the right side. It will take 1-2 days to replace depending on how much help you have. The only other thing that could cause the pully to wobble is if the tapper rings were loose.
 

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Discussion Starter · #3 ·
Southern, your statements were very accurate. We shut down as soon as we found where the vibration was and did some other things before tearing into it yesterday afternoon. Finally got it apart at 12:30 last night and sure enough, there was a hairline crack just outside the right hand bearing. Exactly like yours. Knowing the countershaft was bent, cracked or something when we found the vibration, we located a shaft at Zeiglers and they transferred it to a store 2 hrs from us and we picked it up this morning. We got it put back together this evening. It's definitely a big job to do it all and of course, none of it came apart easy. Hopefully all is good with it now.
 

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Make sure the taper rings are tight. My inner one was loose which caused the pulley that drives the long belt that goes back to the rotors to go up and down. This eventually broke the shaft right off. Hopefully you pressed the tapper rings on or made sure they were tight before you put the bolt on to hold them in place. It is not a job I want to do again. Check to make sure your main 7 v belt is not rubbing on the guides. Even though we marked and tried to put it back in the same place we had to adjust the tin guides to make sure it did not rub anywhere.
 

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Southern, your statements were very accurate. We shut down as soon as we found where the vibration was and did some other things before tearing into it yesterday afternoon. Finally got it apart at 12:30 last night and sure enough, there was a hairline crack just outside the right hand bearing. Exactly like yours. Knowing the countershaft was bent, cracked or something when we found the vibration, we located a shaft at Zeiglers and they transferred it to a store 2 hrs from us and we picked it up this morning. We got it put back together this evening. It's definitely a big job to do it all and of course, none of it came apart easy. Hopefully all is good with it now.
midmofarmer did you find any cause of the shaft failure? I had to change my countershaft on my 2008 590 in 2010 before harvest and before I ever used the new to me machine with only 260 hrs. Before I bought the machine it was very obvious there was a major vibration and the cylinder drive pulley on the right side was wobbling 1/2". We replaced the complete cylinder and shaft with a Sunnybrook. The original cylinder was twisted and several belts were burned indicating plugups by the previous owner, even though he told me "nothing wrong with that combine, it's ready for the field!" After we changed the cylinder and all the belts in the area we worked on , there was still a moderate vibration on the right end of the countershaft (main threshing drive sheave). I rejected the purchase until the vibration was diagnosed. After much arm twisting and with my work we measured the shaft runout at .015". Claas said it was within spec but just. I said I wanted it fixed before purchase. They finally agreed to change the shaft and we found a 10" piece of the backing missing on the 7B main drive belt. My point is there was lots of evidence of plugging/abuse. The shaft did not break but was bent. What is the acceptable as shaft runout to be able to check that with a dial indicator when you suspect a problem?? Also I wondered if the higher hp C13 was linked to failures. SouthernSK had a loose rotor drive sheave that seems to be the culprit. Bottom line in one word, is the problem VIBRATION? My 590 has been good since the repairs and 5 years of trouble free running. What do you think about this midmofarmer? What caused your bend/break? Is every plug up a potential shaft bending cause?
 

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Discussion Starter · #6 ·
Transaxial, we have no idea what caused this and that is a bother. The machine is an '09 and we bought it in '09 with 150 sep hrs on it. It now has around 1000 hrs. We don't know what caused the crack (upon further inspection the shaft was cracked 3/4 of the way around so I feel very fortunate that it didn't break and I'd say it wasn't far from it)

The left hand countershaft bearing was "loose". There was some play in it but it wasn't terrible. IMO, these combines do not run very smooth so a problem that causes a small vibration can easily go undetected until it turns into a big one. I never noticed a vibration or movement on the shaft but that doesn't mean there wasn't. I wondered about belts but I don't see any that are missing lugs or backing or any other problems.

We put the new shaft in and looking back, I am really kicking myself for not putting a dial indicator on it. After it is all together the shaft does not run perfect. There is no noticeable vibration and everything feels as smooth as ever. However by watching the header clutch on the left side and the cylinder sheave on the other, neither one runs perfectly true. We also have a 570 and it has about the same movement. I expected the whole thing to be perfect with a new shaft and bearings. That coupled with the fact that we didn't find a clear cut reason on why it happened, I'm a little uneasy about it. I don't know what else to do but run it and keep a really close eye on it.

As machine abuse, we take good care of our stuff and do regular maintenance. It has been plugged at the impeller a few times. The first time I ever plugged it, I dug it out from the front and cleaned out the rotors and chopper. I pulled what I could out from the side of the cylinder and then tried running the separator to finish unplugging it. I wasn't thinking about the impeller being plugged that tight. I ended up having to dig out the impeller to get it cleared. That was the only time I ever tried to power unplug it and that was several years ago. All of the other plugs have been slow motion type of deals where it slows down and then quits. No foreign objects going through and causing an abrupt stop. I've never smoked a belt on it. It all has me puzzled and concerned.
 

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Midmofarmer I think the reality is the shaft is not big enough for the job. As far as I know I don't think they beefed this up for the 780. The only other thing it could be is they could have had a bad batch of shafts. My 590r is a 2008. I guess time will tell on how long the new one lasts. You are lucky you caught it early. Ours damaged the inside pulley that drives the belt that goes back to the rotors. The pulley is worth about $2000.
 

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Midmofarmer I think the reality is the shaft is not big enough for the job. As far as I know I don't think they beefed this up for the 780. The only other thing it could be is they could have had a bad batch of shafts. My 590r is a 2008. I guess time will tell on how long the new one lasts. You are lucky you caught it early. Ours damaged the inside pulley that drives the belt that goes back to the rotors. The pulley is worth about $2000.
Yes Midmofarmer, it is a concern why these machines seem to have more than an occasional shaft issue. I suspect SouthernSK is correct in saying that the shafts are not heavy enough. With all the examples of breaks and bends on both ends of the cylinder shaft, left end of impeller shaft, driven end (right) of countershaft , there has to be a reason. It would seem that the shafts can easily suffer a slight bend and then the resulting vibration starts to do its damage. Sunnybrook says that they have yet to replace either end of a stub shaft on their cylinder so that in itself is a partial fix to an oem problem. The Lex techs I work with seem to want to change the 3 little round wear bushings on all the VS sheaves every year. I think it is overkill but then again if it helps to minimize vibration maybe it is cheap insurance. I still see too much vibration on these big heavy VS sheaves and have to think that is some of the problem.
 

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Sunnybrook credits their lack of shaft failures (probably for any combine color) due to less weight the cylinder imposes down on the concave.
Maybe their shafts are better too...? Is Canadian steel better than Germany's?
 

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The reason their cylinder shaft does not bend is because of all the weight and inertia that it takes to stop it. It eliminates the high torque spikes. I however have been having a dog of a time breaking APS belts. They no longer slip but just break when they hit a slug. I can not figure out of they are bad belts or if the increasd APS clearance is causing this or what to do. I have broke one every evening for the past three nights. My tightener is tightened to book specs. I will continuemto loosen it. I do notmknow what else to do.
 

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Wouldn't they slip before breaking? Everyone says to over tighten the APS belt, and impeller belt.

I have bought some spare APS and impeller belts. Some of them have smooth, glossy backing and "seem" cheap, compared to the more rubbery, textured belt. I think the smooth one said Mexico on it.
 

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Wouldn't they slip before breaking? Everyone says to over tighten the APS belt, and impeller belt.

I have bought some spare APS and impeller belts. Some of them have smooth, glossy backing and "seem" cheap, compared to the more rubbery, textured belt. I think the smooth one said Mexico on it.
I have not noticed the Mexican belts but did notice the Genuine Lexion feeder chains "Made in China". I was some choked at that and still can not get an answer if that is the only source of chain. Years ago I was breaking header auger belts on a L2 Gleaner. Regular farm supply belts for $20 just did not stand up like the oem $40 belt.
How much clearance are you running from the tips of the aps to the concave? As thick as your pointer finger when the main concave is at 7mm? Have you tried increasing that clearance to say, double that? What crop are you in?
I have never tried a North American power band like Gates. Don't know?? Would not surprise me if they do not fit the sheaves though.
 

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Sunnybrook credits their lack of shaft failures (probably for any combine color) due to less weight the cylinder imposes down on the concave.
Maybe their shafts are better too...? Is Canadian steel better than Germany's?
While I was at the sunny brook factory today I saw a few of these stub shafts and I ask them about it and I'm sure they said they get them from class.
 
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