PTO Wobble

   / PTO Wobble #1  

Madz

New member
Joined
Jun 25, 2015
Messages
15
Location
Australia
Tractor
Kubota BX25D
Guys - I've fitted a post hole auger to my BX25D but am concerned about the amount of wobble in the PTO shaft? Do you think it's okay or is the shaft bent or something else amiss - it doesn't seem right to me, but this is the first time I've used the 3PL?

https://user.fm/files/v2-856ac144323e4ee2b4b7f41b445325e6/PTO Wobble.mp4
(hopefully the linked video works I wasn't sure how to go about that, wouldn't let me attach)

Thanks
 
   / PTO Wobble #2  
I didn’t have any sound with the video, but I would suggest removing the plastic shielding then make your determination. Plastic shielding can be slightly “off” giving the appearance of a bent driveshaft especially on longer shafts.
The plastic shielding may be wobbling, but the shaft could be perfectly straight or have just a slight wobble.

Even if it is bent, occasional use won’t hurt anything. Constant use could affect bearings and u joints long term.
 
   / PTO Wobble #3  
I didn’t have any sound with the video, but I would suggest removing the plastic shielding then make your determination. Plastic shielding can be slightly “off” giving the appearance of a bent driveshaft especially on longer shafts.
The plastic shielding may be wobbling, but the shaft could be perfectly straight or have just a slight wobble.

Even if it is bent, occasional use won’t hurt anything. Constant use could affect bearings and u joints long term.
Very true, my plastic shielding was all over the place, but the shaft was fine.. the video looks like mine, I took the shielding off when I first got it to check...
 
   / PTO Wobble #5  
   / PTO Wobble #6  
Guys - I've fitted a post hole auger to my BX25D but am concerned about the amount of wobble in the PTO shaft? Do you think it's okay or is the shaft bent or something else amiss - it doesn't seem right to me, but this is the first time I've used the 3PL?

(hopefully the linked video works I wasn't sure how to go about that, wouldn't let me attach)

Thanks

The plastic shielding is there for operator etc. safety and is meant to be stationary, not rotating with the shaft.

First secure it as it is supposed to be and see if the shaft still wobbles?
 
   / PTO Wobble #7  
Its just the shroud. if the shaft was bent it'd be shaking like crazy. I guarantee its fine.
 
   / PTO Wobble #8  
You really need to use the PHD at an idle and not running that fast. If the auger encounters something it will immediately shear the shear bolt. Slow it down. Slow also gives you better control.

The wobble is the plastic shield and they all wobble a bit. Some worse some not so bad.
 
   / PTO Wobble #9  
If it was my post hole digger I'd use it with that slight wobble & concentrate my worry's on lack of rainfall in my locale & inflation. At the slow shaft rotation speed that PHD should be operated pto shaft/u-joints should live a long life
 
   / PTO Wobble #10  
The plastic shielding is there for operator etc. safety and is meant to be stationary, not rotating with the shaft.

First secure it as it is supposed to be and see if the shaft still wobbles?

This.
There should be a short section of light chain that clips from the pto shield to the tractor.
 
   / PTO Wobble
  • Thread Starter
#11  
Thanks everyone for such a great response. I'm learning heaps about PTO shafts! I didnt realise the cover should stay stationary, I have greased up the plastic bearings at the end of the cover and looked into the chains. I don't think it's just the cover though as I tried running it with the cover withdrawn and it is still shaking itself to bits (see this vid https://user.fm/files/v2-2c4958d7cb4e6674b0e8085044ff1d1d/my-video.mp4)

So I took the shaft into a local tractor shop but they said they couldn't see too much wrong with it - they didnt think it was bent based on the fact it slid smoothly into itself (expanded/contracted) and there didnt seem to be excessive play in the universal joints.

So I'm still scratching my head a bit here. I'm hoping it's not the auger itself. The only thing I can think of is the shear bolt is a bit small (8mm rather than 10mm) I wonder if that would be enough to cause it? I only have a high-tensile 10mm bolt here, would that be ok given the shaft has a clutch? or does it need to be a "weak" bolt?



You really need to use the PHD at an idle and not running that fast. If the auger encounters something it will immediately shear the shear bolt. Slow it down. Slow also gives you better control.

This is interesting to me as we have a lot of loose rock here and it's definitely going to be an issue - the BX25 at idle though doesn't have any real hydraulic flow/pressure (not sure about the terminology) and the PTO leaver is basically engaged or not, so I'm not sure I'll have much ability to slow it further than shown in that video which was only reasonably low engine revs from memory
 
   / PTO Wobble #14  
Pto post hole augers all wobble, particularly when not in the ground. As was mentioned above, slow and steady is best. Tractor at idle, or slightly above... Go down a little, raise auger, repeat. If you screw the auger into the ground in one plunge you are likely to get it stuck.
Have fun, and be safe.
 
   / PTO Wobble #15  
I think what you are seeing in the video is the u joints working as they should. If you had them level - as in the auger down they would be fine. It looks to me that the u joints are close to the maximum angle when you are in the up position.

g


I would say the U joints in the video are past maximum angle, which is why the clunking noise from the joints!
 
   / PTO Wobble #16  
Most likely the plastic safety sleeve.

I have a 10' Kodiak 2 spindle cutter/mower I bought used. PTO shaft is slightly bent. I just send it. If it were worse, I'd replace or chuck it in a lathe and straighten.

CT
 
   / PTO Wobble #17  
I would say the U joints in the video are past maximum angle, which is why the clunking noise from the joints!
I don't think PHD u-joints are past maximum angle. I wonder if condition of PHD u-joints has been checked lately?

Have you ever wondered similar to me how the u-joints on a 4WD pickup that had a very high lift kit installed survive those extreme angles at high rpm's?
 
   / PTO Wobble #18  
I don't think PHD u-joints are past maximum angle. I wonder if condition of PHD u-joints has been checked lately?

Have you ever wondered similar to me how the u-joints on a 4WD pickup that had a very high lift kit installed survive those extreme angles at high rpm's?



That is a pretty steep angle for regular U-joint shaft which is probably why it makes a clunking sound:

Angle.png



I would not drive a pickup with a regular U-joint driveshaft angle like that - constant velocity, double cardan etc. etc. are a different story.
Each to his own.

Thinking.jpg
 
Last edited:
   / PTO Wobble #19  
Guys - I've fitted a post hole auger to my BX25D but am concerned about the amount of wobble in the PTO shaft? Do you think it's okay or is the shaft bent or something else amiss - it doesn't seem right to me, but this is the first time I've used the 3PL?

https://user.fm/files/v2-856ac144323e4ee2b4b7f41b445325e6/PTO Wobble.mp4
(hopefully the linked video works I wasn't sure how to go about that, wouldn't let me attach)

Thanks
Plaztec quality through and through! I put a new shaft on mine since I lost the front half while not in use and it looked exactly like that when I first used it.
 
   / PTO Wobble #20  
Guys - I've fitted a post hole auger to my BX25D but am concerned about the amount of wobble in the PTO shaft? Do you think it's okay or is the shaft bent or something else amiss - it doesn't seem right to me, but this is the first time I've used the 3PL?

https://user.fm/files/v2-856ac144323e4ee2b4b7f41b445325e6/PTO Wobble.mp4
(hopefully the linked video works I wasn't sure how to go about that, wouldn't let me attach)

Thanks
Hi, Looks like the tractor supply unit I use. That looks normal to me. FYI I learned the hard way not to run it slowly. I work in rocky soil and broke shear pins 1 after another until I talked to Tractor supply support and the fellow said run the rpm up and that he uses his in very rocky soil at high rpm without issue. It works, a little scary though. Those things are tough! I can get hooked on something and it will just kill the engine before I can spill the clutch. Alternately if i hit soft clean digging it will suck right down and lift the front end. Good Luck
1998 New Holland 1630 3 cyl 27 HP FEL.
 

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