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Krone 42T - drive questions


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#1 brookfarm

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Posted 10 April 2021 - 09:07 PM

Hi there - I have really appreciated all the information on this forum over the years, but this is my first post.

 

We just bought a 4-5 year old Krone 42T rake.  As I went to hook up the PTO shaft after towing it home, I found that the driveshaft running through the hollow body has about 1/2" of play forward and back.  I am wondering if this is normal or not.

 

The rake is quiet when running, but it has a bit of a "thunk" at start up, even with a "slow start" PTO on the tractor.

 

Now I am also noticing a 3" hairline crack in the casting where the pinion gear sits (it runs across the pinion shaft).  And when I look in the breather hole I do not see any lubricant (although it is hard to see) and the teeth are not perfect.

 

So - if there is endplay in the driveshaft, does that suggest that the pinion gear is able to move, and therefore come out of alignment with the ring gear.  Am I going to chew up my ring gear as soon as I start raking hay?  

 

 

Or is this all normal and the "thunk" is just play in the system?  Our Kuhn certainly has a thunk if you don't ease the PTO on.

 

 

Overall, I am excited about the Krone - it does seem heavily built!  I looked at Kuhn, NH, Claas, and Kubota.  The Claas seemed very nicely designed, but nothing used.  We have been happy with the Kuhn, but again, nothing used.  The NH and Kubota seemed lightly built, and were still more money than the Krone which looks great - but of course I did not see that hairline crack until I had it home.

 

Thank you for any insights!



#2 paoutdoorsman

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Posted 11 April 2021 - 06:52 AM

Couple things to figure out here to narrow down the thunk.  First you need to determine if it's the slip clutch on the PTO shaft ratcheting on start up, or if it's the actual pinion shaft jumping a couple teeth on the ring gear.  If you happen to have a similar length PTO shaft without a slip clutch, swap it on and engage the PTO.  If you still have the thunk, you likely have bigger issues and I can give you more information on what to look at next.

 

When you say 1/2" endplay forward and back, are you talking movement in and out of the frame tube, or are you referring to the shaft rotational movement - left to right.  ie, backlash?  With the PTO shaft completely removed from the rake, grab the PTO stub shaft where it enters the rake frame tube and rotate left to right to feel your backlash.  This should be very minor.  If it is not, you very well could be jumping the pinion teeth a couple times on the ring gear getting it started.  If the pinion teeth look chewed, this could be what is happening.

 

The pinion shaft is captured in the top housing and the ring/pinion backlash is set with shims on either side of the pinion shaft bearings.  Essentially moving the pinion shaft deeper or shallower in the cast top housing to change the mating depth.

 

Krone uses a special grease to lubricate the ring and pinion, not a fluid, so you really do just see the greasy ring gear teeth when looking into the inspection hole.

 

Now, about that crack.  Would you be able to post some pics?


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#3 brookfarm

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Posted 11 April 2021 - 08:28 AM

Thank you - this is very helpful.

 

The play is in-and-out of the frame tube.  I did not check backlash, but I will.  There is no side to side play - i.e. the bearings seem to be fine, just letting the shaft slide in and out.

 

I like your idea of swapping the PTO shaft - I will see if I can make that happen.  I will also try a tractor with a manual PTO so I have a little more control.

 

And I will post a picture of the crack.



#4 brookfarm

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Posted 11 April 2021 - 10:43 AM

Further followup:

 

There is backlash in the driveline.  I am not sure how to quantify it, but it is roughly 1/2 a spline, meaning that if you start with a spline up, and rotate it until it hits resistance, that spline will now be about 1/2 way into where the adjacent valley was.  I guess that is about 15°.

 

I would say that is more than "very minor", but I am not sure.

 

I have not found a suitable PTO shaft to try, but I did hook it to a manual PTO tractor, and by easing the PTO on, as I normally would, I got no "clunk".  If I pop the clutch it sounds horrible, but very briefly - like it is only skipping a couple teeth, or the ratchet clutch is only bouncing once or twice.

 

Finally, I attached some pictures of the crack.

 

Attached File  393D3B4C-C06C-4205-B1CD-39CA1FE2FD62.jpeg   115.75KB   1 downloads

Attached File  C7EB32FF-7656-41B5-882B-5843EB15C5A7.jpeg   124.16KB   1 downloads

 

Thanks again for your input!

 



#5 paoutdoorsman

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Posted 11 April 2021 - 02:14 PM

The play in and out isn't a huge deal and isn't anything that would really cause you an issue.  Check if the lock collar on the bearing on the front of that shaft has come loose.

 

15 degrees is too much backlash.  You need to determine why it has that much.  There is a sight hole on the side of the main frame where it bolts to the cast housing.  Only about an inch or so in diameter.  Just to be sure it's not an issue with the rear universal joint on that drive shaft, look through that site hole while someone else rotates the stub shaft back and forth as if checking backlash.  Make sure that this universal joint appears tight and moving in unison with the person rocking the shaft.  Very unlikely to be an issue, but possible.  If that checks out good, do this:

 

Look at the underside of the cast housing, where it meets the rotor.  Compare the gap where the two meet at the rear center vs. the gap where they meet at the front center.  Are they relatively close to the same, or is the gap at the back a lot less than the gap at the front?

 

Regarding that crack... I've seen these rakes cracked here before.  It isn't really a structural issue if it doesn't keep spreading - however if the rake is going to sit in the weather, it can seep water which will eventually cause you issues.  That moisture will be trapped in the ring gear housing and cause rust or corrosion.  Welding it will both reinforce it, as well as seal the crack.  At a minimum, put a bead of sealer on it if it will see rain. 

 

Do you know what year the rake is?



#6 brookfarm

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Posted 11 April 2021 - 03:31 PM

This is very helpful, thank you again.

 

The lock collar on the bearing does not appear to be tight.  I have not tried to tighten the set screw, but the shaft slides freely through the collar and the screw seems out a bit further than maybe it ought to be.

 

Using the sight hole, I would say the rear universal joint is fine.  There is no apparent slop between the front of the shaft and that joint.

 

 

I think I understand you about the gap under the cast housing, but I'm not totally sure.  The cast part sits on top of a steel "plate" which is conical towards the center.  That conical portion sticks up into the cast housing.  The gap between the stamped steel and the cast housing is not consistent.  It is about 1/4" at the front and much less at the rear.  The paint is worn off the steel in a band as if it is rubbing the casting at the rear - although the band is rusted, so it seems like it is not rubbing just now.

 

I am glad to hear the crack is not terminal.  I hope to keep it under cover, but I can certainly seal it.  I don't trust my welding enough to try that approach.  

 

I think it is a 2016.

 

I look forward to hearing what that inconsistent gap indicates!



#7 paoutdoorsman

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Posted 11 April 2021 - 08:54 PM

Boy, I was hoping you didn't say that...

 

There is a vertical shaft that connects the running gear chassis to the top frame.  It's the only thing connecting the running gear on the bottom to the main frame on the top.  A backbone of sorts.  If the rake was run hard over really rough ground, that backbone can bend.  Even the slightest bend in that shaft will increase the gap between the cast housing and the stamped steel rotor top plate at the front and decreases the gap at the rear.  At the same time the pinion gear moves away from the ring gear, increasing the backlash.  Ideally this is caught and fixed before the ring and pinion gear set sustains too much wear because that's an expensive gear set.

 

The original shaft is pretty stout, but Krone also makes an extreme duty shaft kit if bouncing across rough ground and high speeds are in the rakes future.



#8 brookfarm

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Posted 11 April 2021 - 09:59 PM

Ahh - Well, you confirmed my guess from looking at the parts diagram.  I was hoping there might be some other explanation!  

 

So, what next?  Is it possible to get a service manual for these rakes?  I have not dealt with Krone equipment before but a quick search doesn't turn up anything.

 

It seems fairly straightforward to break it down - maybe a bit time consuming.  But it would be nice to have some guidance putting it back together - particularly if there are clearances that need to be kept, like the meshing of the pinion and ring gears.

 

Anything in particular to look out for?  Is it more complicated than I am thinking?

 

That extreme duty kit might make sense.  Are there down sides to it (other than the price, which I assume is higher)

 

Thanks again for your help - it has saved me hours of head scratching!


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#9 paoutdoorsman

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Posted 12 April 2021 - 07:16 AM

You're welcome, glad I could help.  I've fixed a few of these rakes with this issue, and I was in your shoes at one time trying to make sense of everything.  It's not all that complicated, just a little time consuming.  I'm not sure Krone will sell the service manual or not.  I'm thinking it is intended for dealers only.  I do have a few critical pages as it relates to the ring/pinion backlash.  I'll send those to you if I can find them.  But that is the only thing that you would really need it for.  Everything else is very straight forward, and I can try to help if you get stuck along the way.  In a nutshell, here is your process:

 

1. Unbolt and remove the rear SMV sign and frame from the rear, and the safety guards and curtain from the sides.

 

2. Pull each set of tine arm bolts and pull the tine arms out of the rotor.  I would pull the bolts from 3 arms initially, then wiggle the center arm from those three loose.  After that just work your way around the rotor pulling the arms.  A 16 model should have the folding tine arms, so just stack them in order they were removed, or remember the proper spacing so the folding arms get put back in the correct order.

 

3. Make sure the rake is in the lowered position and disconnect the hydraulic raise cylinder hose where it meets the steel line at the rear of the main frame.  Pull it down through the center tube.

 

4. Remove the PTO shaft and unbolt the bearing retainer flange bolts at the front of the frame.  Slide the drive shaft out of the main frame.  If the drive shaft is tight on the pinion stub shaft inside the frame, just release the bearing lock collar, and pull the bearing assembly off.  This makes it a little more difficult to remove the main frame as you will have to slide it completely over the drive shaft.  Since you said your drive shaft moves in and out 1/2", this should not be the case.

 

5. Now to separate the main frame.  I like to support the under carriage with a floor jack, then if possible support/suspend the main frame from overhead.  A couple of fellas can manhandle the main frame easily enough too and just walk it away and set it down.  Once both are supported, pull the 6 bolts holding the main frame to the cast rotor housing.  Carefully separate the frame from the rotor housing and roll the undercarriage away to the rear.

 

6. Remove the top center screw holding the cast rotor housing to the vertical shaft, then lift the rotor housing up off the shaft.  There will likely be a few shims on the shaft or stuck to the underside of the rotor housing.  Whatever was necessary to set the original backlash correctly.  You may need more or less of these on re-assembly.

 

7. Remove the upper rotor housing, the cam track, spacer, and lower rotor housing.  Depending on the curvature of the shaft, these might be a fight.  :o

 

8. Replace the shaft, and reverse this process.  There were two styles of shafts.  One bolted to the undercarriage with 6 bolts radially around the shaft, and the other passed through the undercarriage and used a big screw similar to the one used on top to secure the rotor housing.  Out of curiosity, which style do you have?

 

To give you a better idea, you can see the curvature of the shaft from the first 42T I had in these pics.

 

42tshaft2.jpg

 

42TShaft1.jpg


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#10 paoutdoorsman

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Posted 12 April 2021 - 09:51 AM

Here are some tear down pics I have from a 46T that I did to give you a bit more of a visual.

 

46T_1.jpg

 

46T_2.jpg

 

46T_3.jpg

 

46T_4.jpg


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#11 brookfarm

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Posted 12 April 2021 - 10:21 AM

Wow - This is super helpful!

 

I really appreciate it!

 

To answer your question: I believe my shaft is the same as the ones you show, with a bolt flange on it.

 

As for the arms, they are not folding.  It seems like this may be an early 2016 - serial 906722.  






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