Combines 850 shaker shaft

I assume this is a carryover from the 750's. my shaft broke on an early 750 after a few thousand hours and the replacement shaft outlasted the rest of the machine. It just broke because of age I suppose. apparently this is a known problem with the 750's and I assume 850's as well. I am sorry, I cannot remember if there are any special instructions for replacement

I have parted out a lot of 750 combines and it seems when people have trouble with the shaker shaft it is because the clean grain pan becomes loaded up with dirt and chaff. the extra weight seems to cause problems. We use a pipe with a hoe on the end to keep the pan clean and never have had any problems. Sometimes the bearing on the left side will wear and have slack causing a hammer type action

One thing you might want to check is the shaker shoe I have seen them crack after the shaker arm goes out depends on how soon you caught the problem

Had someone in this area that broke this shaft before. I was combining in the same field,(frozen soybeans and snow) when it happened. Agree with the others in that any play can cause hammering, and hairline fractures which may fail at some point. look closely at pitman, stub shaft for pitman on pulley, shoe and grain pan. Usually excess weight on pan will break pan before shaft, but pan should be hoed off regularly. Check alignment of all components. Incidentally, this guy replaced his with one from Massey and it broke again the following year. At second failure, he had a machine shop build one heavier. Seems to me his broke inside lH bearing, arm and pitman still functioned normally. He never had a problem again. To replace, remove seives and climb inside to remove pivot pins(air hammer works great). Remove pins from grain pan at sides and block pan up. Believe you can pull shoe rearward far enough, and think there is a piece of tinwork to take out at top of fan housing. Shaft should remove out right hand side. Check for any shimming required to align and square shaft in machine.

The later model 850s had the bigger shaft, not sure what serial number. If you fit it you also need the bigger bearing carriers and bearings and that seemed to stop the problem but as a post said above check the pitman arm as they wore around the bottom bearing and caused jerking of the sieve box.