Combines Main Shaft and Bearing on R 52

[Harvester]

The large nut on the right side of the mainshaft needs to be tight... 450 ft lbs tight, otherwise the bearing can fail, and that you should check the torque on this nut at least every year. At a combine school a while back, the fellow said that you don't need an expensive torque wrench to do it, just a 3' cheater pipe and a 150 pound guy at the end. Thought that fits my operation just fine.

 

[natek]

You are right about keeping the nut tight on the right side but I think the torque is up to 600 or 650 ft lbs now with the new shaft. There is a bulletin on this so you can check with your local dealer. We just put one in 2 weeks ago and that is we torqued ours to 600. Hopes this helps natek

 

[NDDan]

Thats terrible. Is shaft being replaced or rebuiltIJ Is bearing actually failing or is it eroding away the shaft fromIJ If it is left side you need to make make sure bearing is free to pivot in bearing holder and bolt is tightened to 350 foot pounds. If it is the right side you need to be sure bearing fits free in holder and holder is square to side frame. Inner race needs to be squished tight to shaft. This is done by tightening nut up to specs. which is minimum of 350 foot pounds. Torqueing up to specs. will not crimp bearing to shaft if hub has been damaged from running loose. You need to check this hub if it is the right side you are having trouble with. There is some chance you can have hub trued up square with the world in a lathe and then use washer to make up the lost material. If you put together and washer next to nut bottoms against shaft you need to increase length of hub. This same thing holds true whenever there is a large nut or bolt holding things on. I don't know how many times I've watched someone put adjustable wrench on nut or bolt and wrap a few times with hammer and call it good. Get this stuff tight in the begining and you'll likely find it won't move even after some use. If it has been allowed to run loose a long time you will likely have hub stuck in that position and tightening the nut will not bring hub up tight against bearing. In that case you could have bearing come loose on shaft before or after it starts to go out on you. I hope that makes sense and please ask if I confused you. Other than a bearing getting tired after many many hours you should never need another mainshaft. Good luck

 

[NDDan]

Sorry I forgot to mention a couple things. Bearing inner race is ussually a just fit to slight interferance fit to shaft. To tight or to loose for whatever reasons needs to be corrected. I can only think of couple places over the years that Gleaner expected interferance alone to keep it tight to shaft. Anyway what I was going to say is we like to use pipe that fits inner race to install bearing. We try very hard not to knock on bearing. If we do have to knock it on we make double sure that seals did not come partially or completely off. Alot of times you can not see the one seal after assembly so we have made tool to pull bearings on. Nothing to special. Just a piece of threaded rod welded onto whatever secures the drive when all together. In the case of any Gleaner I can think of since 1988 on the right hand of mainshaft we use that nut but have to grind down to fit inside the pipe that is pressing against inside race of bearing. Come to think of it (knocking on wood) we still haven't pulled a single one piece mainshaft since '88. Yes we replaced a bearing hear and there but never had any shaft damage so just replaced in machine. That tells me that anyone with shaft failure or worse yet a repete failure has something very correctable going wrong during assembly. Catch ya latter.

 

[Harvester]

Nature of the beast, but the cause is generally the same, unless it happens to be a defective bearing, in that the loss of adequate preload on that bearing will cause it to fail prematurely, hence the need to retorque the mainshaft nut on right side yearly or from time to time. In my book it's 450 ft lbs for the R52 and 600 ft lbs on an R62_R72.

 

[NDDan]

Your R50 and 52 have the same bearing as does the first few years of the N7s. N7s would have in the range of at least 20% more power and the shaft runs about 10% slower. The slower speed would add torque or pull on shaft. N7s can have same problem with bearing wearing away shaft if nut isn't torqued up or hub has eroded away from running loose. In 2000 the shoulder on mainshaft was enlarged to allow 600ft.lbs. of torque on nut. If you had the newer shaft installed you can observe the higher torque. If you have observed the tips given a few days ago you will not lose another shaft. Replacement side sheets or repair panels are available so I would be the last one to say you are the only one that has had a problem. Believe me I have seen a great variety of operators in combines and some won't stop until flames are flying. I am not saying that loose bearing on shaft is extremely noticeable but something should be before side frame gets it. I'm tring to help you get yours right before it happens again and it would be nice of you to transfer what you have learned to the others that have had trouble. I'm worried you still may have problem if your damaged sidewall isn't fixed or hub is eroded away ect. Please look over tips closely and share with dealer if they are involved. Have a good day.