Combines Wobble Box rebuild

[vstk]

Ed, I cant say i have ever put a temp gun to one.....they do run somewhat warm, but put in numbers that sounds hot. Yes, they do set up kinda tight but the first thought i had was , how did you measure the rolling torqueIJ And then how did you set the bearings that are shimmedIJ As for the sickle being free to move that is important but I would bemore worried about a couple other parts of cutter bar that could cause excessive load. All the things you all ready know about.....sections, guards(they some times get overlooked),and wear plates and hold downs. I set my wear plates by pulling them all the way forward and getting rid of the slack and then tapping them back just slightly. I set my hold downs to just clear the sections. I then roll it by hand and make sure it can not bind up in normall stroke. I have sen a lot of heat tranfer from belts. be sure the belt isnt slipping.........this can be a tough one to find some times. I know it should seem obvious, but it some times just slips ebough to get hot. Not sure this helps at all........... how is harvest goingIJ Van

 

[Ed_Boysun]

Hi Van, Thanks for the response. About done with harvest here. Had about 70 acres left when the sickle head pulled in two. This is more of a for next year thing. Setting the rolling torque took some figuring to come up with a method. Book says to put a dial type torque wrench on the small nut and watch the indicator, but we tried that and it looks like a complete joke. The crank is going every which way and I couldn't see how you could get any kind of a reading at all if you hold the trunnion and spin the crank. Funny thing though: if you hold the crank in the vise and slip a 6 inch diameter tube over the bearing studs on the trunnion, it's a nearly perfect fit. You then have a 6 inch diameter circle. I cut about a four inch long section of the tubing and made a place to tie the pull wire to it. Fish scale on the end of the wire and multiply the reading obtained when the thing is spinning by 3 and you're pretty close to the inch _ lbs. of rolling torque. (At least I think soIJIJ We were seeing 8 to 10 max) End capped bearings run perfectly cool until they pick up a little heat from the trunnion. We set preload by shimming until we had measurable end play and then removed shims to come up with .020" preload. Belt and belt pulley seem to be running cooler than the trunnion, so doubt a slipping belt is the cause. An IR temp gun is a very handy thing to have around if you are working on a combine. Old dirt-farmer specs on the trunnion temp is: You can touch and hold fingers there for a couple seconds without burning your finger-tips. Does that sound too warm to what you're seeingIJ Ed in Montana

 

[vstk]

Ed, My first thought is........ya maybe a bit hot......but if you arent seeing discoloration or if it does not look like you are doing the grease any bad things........maybe not. I'll ask what may seem like an obvious question. When you put the center housing together, did you put the pressure relief for the grease back in and how did you position it in the boxIJ And you did pump it full while turning until it "popped off", rightIJ I have never set the rolling torque for the wobble box that way. I have always used a dial torque wrench........and I agree it looks odd........but it does work OK. I have set final drives and other things with your method. It sound like you set up the shims right. When you had the trunion assembled before you put it in the box, the crank preload should have felt similar to the other bearing preload. Yes, I agree, a temp gun is great. I use them more on cotton strippes than combine bearings. All those bearing on row headers are hell to get to. Van

 

[Ed_Boysun]

Finished harvest yesterday and I think it's going to be OK. Temps were running 155 on the trunnion. Bearings were packed before they went on the crank. The seal on the pulley side was left off and it was greased until grease came out evenly all around the bearing. After the seal was installed it only took a couple strokes on the gun until grease came out of the relief port. We didn't take either the port or the zerk off the trunnion housing. Thanks again for the encouragement. last wobble box replacement I did was a dealer rebuild. That one lasted about 3 days and I ended up buying a new one for that header. I inquired about a new one for this header but the parts man was hesitant to price one, so we rebuilt this one. We'll see next year if we're any better than the shop re-builders. Only have to cut with it for another day to beat their record. Ed in Montana