Can't remove propshaft from gearhead on rotary cutter.....ideas?

[Flintknapper]

OK guys....I'm not usually one to give up easily.....but this one continues to kick my behind. And yes, it has had an ocean of penetrating oil applied.

This economy level Rotary Cutter came with a tractor I purchased recently. I was wanting to pull the prop-shaft...clean it up and grease it since it looked like the U-joints were fairly dry and the cutter had been attached for quite some time.

Shear-Bolt was bent but not sheared. I had to drive it out with a drift punch and 3lb. hammer. The yoke on the prop-shaft at the PTO end (tractor) came off easily enough. BUT....the end on the gear-head will not budge.

I've tried a punch and hammer....No Go. Tried a brass hammer on the U-Joint yoke.....Nope! Applied some heat (propane torch) and used a steel block and tapered wedge to try to separate or at least get some movement. Nothing doing........

There is no snap ring or anything holding it in place. I believe it has just 'rust welded' itself together. I know copious amounts of heat would help but that might also take out the input shaft seal on the gear head.

Thinking I might get a second steel wedge tomorrow so I can apply more even pressure.....but I am open to ideas.

 

[Jhilde]

Can you flex the u- joint enough to get an air hammer in there? Or better yet split the u- joint and pull the yoke off.

 

[BigG]

I would run a drill bit in the hole where the shear bolt goes in order to clean it up. Secure the mower to a tree. Wrap a chain around the yoke and gently pull on the chain with a come along. Touch the backside of the yoke with a chipping hammer. Should come apart.

 

[ken erickson]

Is the shaft hole drilled/bored clear thru to the u joint side? If so, perhaps a large universal type gear puller would do the trick

. Of course the u joint would have to be removed .

 

[Flintknapper]

Can you flex the u- joint enough to get an air hammer in there? Or better yet split the u- joint and pull the yoke off.

Yoke is too close to the gear-head and too steep an angle to do any good with an air hammer, but splitting the U-joint might be possible, then I can attack it in a completely axial direction with a puller.

I'm not sure the U-Joint doesn't need replacing anyway. This thing has been on there a LONG time from the looks of things.

 

[mcfarmall]

There has to be something to prevent the yoke from sliding off the gearbox input shaft when the bolt shears. You said there was no snap ring, how about a spiral ring or wire ring or a roll pin drilled off center that crosses a groove in the input shaft.
Put a smaller diameter bolt in the hole and start mowing.

 

[Flintknapper]

Is the shaft hole drilled/bored clear thru to the u joint side? If so, perhaps a large universal type gear puller would do the trick View attachment 79644 . Of course the u joint would have to be removed .

This might just be the ticket. I have some large pullers (up to 20 tons) that should move it. I think running a drill bit down through the hole also (if it hasn't already moved any) could be beneficial as well. It doesn't take much of a raised edge or burr to jam the thing.

 

[Flintknapper]

There has to be something to prevent the yoke from sliding off the gearbox input shaft when the bolt shears. You said there was no snap ring, how about a spiral ring or wire ring or a roll pin drilled off center that crosses a groove in the input shaft.
Put a smaller diameter bolt in the hole and start mowing.

There is a shallow groove that looks like it could accept a snap ring of some sort....but there isn't anything there and no other feature to capture it. Its just rusted on there and a fairly close tolerance fit.

 

[ken erickson]

There is a shallow groove that looks like it could accept a snap ring of some sort....but there isn't anything there and no other feature to capture it. Its just rusted on there and a fairly close tolerance fit.

I seem to remember that on my King Kutter yoke there was a snap ring. That is what would insure the yoke stayed on the shaft if the shear bolt broke. Is there any chance that that the snap ring is still there but not visible due to the rust etc? That would be an awfully hard pull if indeed it was there.

 

[NCL4701]

You’re definitely right to get it freed up. If it’s rust welded the shear bolt isn’t really protecting the drive train.

If there isn’t a snap ring or something similar to keep the yoke on the shaft if the shear bolt shears, there’s no way I would run it until that’s rectified. If it comes off the mower end while it’s running the PTO shaft can flail around and bash in your head or some other body part you might prefer to keep. If it doesn’t hit you it’s almost certain to beat the crap out of the back of your tractor while destroying the PTO shaft.

 

[Brandonorr55]

Look closely for a roll pin or Allen set screw. . Had the same issue recently and found it under a bunch of gunk. Knocked out pin and shaft sled right off.

 

[Flintknapper]

I seem to remember that on my King Kutter yoke there was a snap ring. That is what would insure the yoke stayed on the shaft if the shear bolt broke. Is there any chance that that the snap ring is still there but not visible due to the rust etc? That would be an awfully hard pull if indeed it was there. View attachment 79665

There is a groove for one...but it is definitely NOT there. Also the snap ring (when present) would be fully 3/4" out ahead of the yoke. My issue is I can't get the yoke to break loose from the input shaft on the gear head at all.

 

[Flintknapper]

Look closely for a roll pin or Allen set screw. . Had the same issue recently and found it under a bunch of gunk. Knocked out pin and shaft sled right off.

Definitely not one.

 

[Flintknapper]

You’re definitely right to get it freed up. If it’s rust welded the shear bolt isn’t really protecting the drive train.

If there isn’t a snap ring or something similar to keep the yoke on the shaft if the shear bolt shears, there’s no way I would run it until that’s rectified. If it comes off the mower end while it’s running the PTO shaft can flail around and bash in your head or some other body part you might prefer to keep. If it doesn’t hit you it’s almost certain to beat the crap out of the back of your tractor while destroying the PTO shaft.

Yep, that was my concern as well. The shear bolt in it (even though slightly bent) was doing NOTHING to protect gear head because the yoke can not turn on the input shaft.

And even with the shear pin/bolt removed now....I don't want to chance breaking free the yoke by blocking a blade and engaging the pto. Just too risky. Don't want to have to replace a bevel gear.

I really think the issue is that rust between the two surfaces has created a sort of corrosive bond. Apparently the previous owner had never heard of anti-seize.

 

[Russell King]

Try driving the yoke towards the gearbox and then clean up the groove some. I assume that the groove is about a quarter inch back from the end of the input shaft. My mower has a circlip in a groove to retain the pto shaft if the shear pin fails.

Also you may have to get the shaft (and mower) vertical and then fill the yoke with a good penetrating oil like PB Blaster or Kroil or Deep Creep.

If you have been using WD-40 as penetrating oil those named above are much better.

If you can use a punch to drive it towards the gearbox even a bit then you’re sure to get it off. You may have to drive it back and forth to get it lubricated

 

[Flintknapper]

"Russell King wrote:

Try driving the yoke towards the gearbox and then clean up the groove some. I assume that the groove is about a quarter inch back from the end of the input shaft. My mower has a circlip in a groove to retain the pto shaft if the shear pin fails.

The yoke is not moving ANY direction. Not forward, Not Backward, Not spinning. As previously stated, there IS a groove for a snap ring/circlip but no snap ring in place. Which is not the problem anyway. The groove and exposed shaft are smooth.

Also you may have to get the shaft (and mower) vertical and then fill the yoke with a good penetrating oil like PB Blaster or Kroil or Deep Creep.

It has pretty much been 'drowned' in penetrating oil at this point. Part of the shear bolt broke off in the bore of the shaft....effectively plugging it. So I filled the hole many, many times and it seeped out 'somewhere'.

If you have been using WD-40 as penetrating oil those named above are much better.

No....not WD. PB blaster and Clover.

If you can use a punch to drive it towards the gearbox even a bit then you’re sure to get it off. You may have to drive it back and forth to get it lubricated

This is a small Rotary Cutter (4' with a 30 hp rated gear head). Not going to 'wail' on it and damage the bearings and gears inside. Better to use a puller against the shaft and yoke. I agree that getting it to 'move' at all....pretty much insures I will be able to get it off. Its simply corrosion between the two surfaces I believe.

We will see. Thank You for the reply and input.

 

[Motion]

I'd suggest removing the "U" joint ( it's probably time for both to be replaced) polish the shaft between the yoke and gear box and drive the yoke rearward, there's got to be some type of retainer to restrict the shaft from coming off in the event of a shear pin failure. I certainly would operate that type of drive without something. Let that drive shaft come out while operating and you'll really enjoy rebuilding the the PTO section of the tractor, plus the cost of new underware, at 540 RPM it's a real attention getter!

 

[NCL4701]

Sounds like you know where to go from here: chase shear bolt hole with drill bit, disassemble U joint, apply largest puller you can get on it, if that doesn’t pull it off hit it with hammer/air hammer while continuing to pull.

 

[Flintknapper]

Sounds like you know where to go from here: chase shear bolt hole with drill bit, disassemble U joint, apply largest puller you can get on it, if that doesn’t pull it off hit it with hammer/air hammer while continuing to pull.

Well....I have to say 'It put up a good fight'. Getting the Ujoint out was a feat in itself, but finally got that done and down to the yoke. After a couple of broken 1/2" bits (and having to punch them out) I rigged up a carbide burr and was able to bevel the hole in both sides of the input shaft, insuring no metal shards/dings were holding it back.

After that.....I set up a 4 ton/2 Jaw puller and put a LOT of pressure on it. The Yoke didn't budge, in fact...I'm sure I heard it laugh.

Not to be denied....I got the big gun out (20 ton/3 jaw puller) and 3/4" breaker bar.

Even with that....it would build up pressure where you would think the whole darn thing was going to fly apart, then it'd 'Pop' and move about 1/8". Did that the entire way off.

As first suspected....the Yoke and Input shaft had simply 'rust welded' themselves together.

I will install new U-joints and apply a 'generous' amount of anti-seize to the shaft when putting the yoke back on. Don't want to do this again.

 

[Quick]

Hahaha! "Oh, yes you are!"