Hi, I inherited an old rotary cutter (about 30 years old at this point). It still works great, but the driveline needs to be replaced, and I can't figure out how to remove it from the gearbox shaft. It looks like maybe it's supposed to be bolted on, but one side of the hole just has a deformed piece of metal poking out and the other side looks empty. I've attached some photos. Can anyone help?
Removing PTO driveline from old rotary cutter
- Thread starter jclr
- Start date
That round smooth top is a pin that is held in place by a spring. Apply some of your favorite solvent (like kroil, PB blaster) around that pin. Maybe tap it with a small ballpeen hammer. It should eventually move down flush with the housing that is on the splined PTO shaft. When the face of that pin is flush with the housing pull the PTO away from the tractor, and it should slide right off.
That pin has a notch carved out of the inner part that allows the PTO to slide on and off the splined shaft. When the pin is released it should spring back as you see it in the picture and lock onto the tractor PTO. ALWAYS be sure that pin is sticking out as you see it in the picture to confirm the connection is secure.
That pin has a notch carved out of the inner part that allows the PTO to slide on and off the splined shaft. When the pin is released it should spring back as you see it in the picture and lock onto the tractor PTO. ALWAYS be sure that pin is sticking out as you see it in the picture to confirm the connection is secure.
Show us the other side of the pin. It looks like a shear pin to me. It may be broken. It is in the center of the shaft. I don't believe it's a quick disconnect. I believe your shaft is round and not splined. If so you may have a snap ring on the end of the shaft as well.
Take a photo from this angle.... to see if there "spines".
Might help to clean up the area but my guess is smooth shaft and this is what is left of a shear bolt. Punch it out from the first photo (get a clearer photo of that first photo).
Might help to clean up the area but my guess is smooth shaft and this is what is left of a shear bolt. Punch it out from the first photo (get a clearer photo of that first photo).
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It looks to me …to be a shear-bolt …which has been snapped… with the Hex-Head portion still inserted.
Use a punch or another bolt, inserted into the hole, and a hammer to drive the half-broken shear-bolt out of the gearbox drive.
(You might make this an easier task to use a wrench on the hex-head to turn the bolt counterclockwise (just in-case someone has foolishly threaded the gearbox shaft.
It never ceases to amaze what some folks do to “farmerize” their stuff.)
Use a punch or another bolt, inserted into the hole, and a hammer to drive the half-broken shear-bolt out of the gearbox drive.
(You might make this an easier task to use a wrench on the hex-head to turn the bolt counterclockwise (just in-case someone has foolishly threaded the gearbox shaft.
It never ceases to amaze what some folks do to “farmerize” their stuff.)
NCL4701
Well-known member
Equipment
L4701, T2290, WC68, grapple, BB1572, Farmi W50R, Howes 500, 16kW IMD gen, WG24
I have a similar age Howse that uses a shear bolt where your “pin” is and a circlip on the end of the shaft to hold the yoke on. The shaft is smooth so the yoke will free spin on the shaft if the shear bolt breaks. The circlip keeps the yoke from sliding off the shaft so the PTO shaft doesn’t become a wildly spinning implement of mass destruction if the shear bolt breaks. To remove the yoke from the gearbox, first remove the shear bolt (or what’s left of it), then slide the yoke toward the gearbox to access the circlip (you might have to disassemble the U joint if that still doesn’t get you enough room to remove the circlip), pop off the circlip, and the yoke will slide off the shaft.
If it has a smooth shaft, pretty confident the above is correct. If it has a splined shaft that pin is more likely a push button release as described by others above. If it’s a splined shaft, there should be a shear pin or slip clutch elsewhere in the driveline. If there isn’t, that strongly implies smooth shaft with shear pin.
I’d start by sticking a finger up in that yoke to see if I could determine for sure if it’s smooth or splined. If that didn’t work, I’d stick a little mirror in the yoke and look at it. If that didn’t work either, I’d look for another shear pin or clutch in the driveline and assume it’s splined if there’s overload protection elsewhere; smooth if nothing elsewhere.
If it has a smooth shaft, pretty confident the above is correct. If it has a splined shaft that pin is more likely a push button release as described by others above. If it’s a splined shaft, there should be a shear pin or slip clutch elsewhere in the driveline. If there isn’t, that strongly implies smooth shaft with shear pin.
I’d start by sticking a finger up in that yoke to see if I could determine for sure if it’s smooth or splined. If that didn’t work, I’d stick a little mirror in the yoke and look at it. If that didn’t work either, I’d look for another shear pin or clutch in the driveline and assume it’s splined if there’s overload protection elsewhere; smooth if nothing elsewhere.
It seems that it's a smooth shaft, with a snap ring. I managed to punch it out a bit (see photo), but it wouldn't budge much more. I sprayed penetrating oil in and I'm going to let it sit for a bit. I think I will be able to get it off now, the trick will be securing a new one, although I imagine that's just a new shear bolt, from all the comments here.
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I believe as others have said it's supposed to be a shear bolt, and someone forced a pin into the shaft. Some do have a snap ring but some have shafts with an angular ring cut into it and a set screw to allow the shaft to slide off, once the pin is removed. Once everything is cleaned up I'd suggest applying anti-seize and a correct shear bolt (Grade 2 or 5 with nyloc nut). Purchase additional shear bolts.
It seems that photo shows a smooth shaft which uses a shear-pin/bolt… and also have a zerk-fitting for greasing…. (might help a bit).
Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
You should have a hole in the opposite wall of the PTO yoke. Someone asked you to take a photo of that to he identify if it was a shear bolt style or not. Since then you have verified that you have the style with the shear pin.
I would recommend not hammering on it too much or too hard unless you put some blocking beneath the yoke to support the shaft in the gear box. There is a bearing in the gear box that you could damage by hammering on it.
I would turn the shaft so the hole is at top (noon) and the pin is at the bottom (six o’clock) and try and apply a generous amount of penetrating oil into the hole. That should help get into where the pin is stuck. Then block the shaft with wood blocks with a steel block on top. Then try to use a punch pin to drive it out. If it doesn’t move much then let it sit for a day or two and try again. You might want to try tapping it in both directions if it doesn’t want to move much. That might get it to get the penetrating oil further into the joint.
If you are in more of a hurry or it doesn’t move then try to drill it out but be careful to not damage the hole by drilling it off center. I think I would try drilling it out through the hole. If not that direction I would try to cut the stub off flat and center punch it and then start small and work your way up in size of drill bit.
I would recommend not hammering on it too much or too hard unless you put some blocking beneath the yoke to support the shaft in the gear box. There is a bearing in the gear box that you could damage by hammering on it.
I would turn the shaft so the hole is at top (noon) and the pin is at the bottom (six o’clock) and try and apply a generous amount of penetrating oil into the hole. That should help get into where the pin is stuck. Then block the shaft with wood blocks with a steel block on top. Then try to use a punch pin to drive it out. If it doesn’t move much then let it sit for a day or two and try again. You might want to try tapping it in both directions if it doesn’t want to move much. That might get it to get the penetrating oil further into the joint.
If you are in more of a hurry or it doesn’t move then try to drill it out but be careful to not damage the hole by drilling it off center. I think I would try drilling it out through the hole. If not that direction I would try to cut the stub off flat and center punch it and then start small and work your way up in size of drill bit.
After many trials and tribulations, I got the pin out! Now I need to try and get the yoke off the shaft. I believe there is a lock ring that I'll need to get off, but even then, I'm not sure how seized it is on there. At the end of all this, it may just be time for a new rotary cutter.
Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Since there is a grease zerk on the PTO yoke you should be able to use that to force grease or penetrating oil into the joint. Hopefully it was greased often enough that it didn’t rust up.
To remove the circlip you have to push the PTO yoke towards the gear box, then the clip can be seen and removed. There should be two ears on the circlip that have holes in them. You can use the proper pliers to remove the clip if you can get a good set with angled ends. I just use needle nose pliers and grab one ear and pull it up and off the shaft.
Glad you are making progress.