BHT Revised: 02 Sep 2013
PTO Shaft Tips
The PTO shaft on the Hawkline auger I just started to assemble is truly an interesting puzzle. Here are some tips to solve the Eurocardan PTO shaft puzzles. Part of the assembly process for the Hawkline auger, purchased through Northern Tool, is attaching the implement end of the PTO shaft to the 40 horsepower gear reduction box. All modern PTO shafts have excellent safety shrouds, shrouds that have one problem, they can be a bear to figure out how to remove! And even worse how to reassemble, sometimes truly a puzzle.
Well what about the shaft's manual?
Well, I did not even receive a manual for the entire auger. One thing I will say is, so far I am very impressed; with how sturdy this low cost auger is. 40 horsepower gearbox and 3 inch (OD) heavy steel tubing throughout. But the only way I know it was made by Hawkline is by the shipping documents that arrived with the PTO auger. Fortunately, I was able to easily find the Hawkline website, which contained a very nice manual regarding this auger.
While there were some specifics about the PTO shaft, the secrets or puzzles, which prompted these tips were not to be found in the manual. I did know it was a Eurocardan PTO shaft. This apparently is an Italian product. While there was product information at the website, I certainly found no actual manual.
Assembling the PTO shaft to gear box
One step in assembling the PTO auger (post hole digger) was attaching the PTO shaft to the gear box. To do this one must somehow gain access to the U joint hidden by the very extended shroud on the PTO shaft implement end. How do you retract this shroud? And there is yet another problem to solve, the PTO shaft safety mechanism (shear bolt) is not implemented in the way the manual implies and yes there is a part missing as well. Fix the PTO shaft retention problem will be another article in itself.
How to properly retract, and reinstall, the PTO shaft's safety shroud (cone) took about four hours of my time to discern!
So what are the shaft's secrets?Here is a close up of one end of the PTO shaft. The PTO shaft cone is marked with a lock/unlock insignia implying that if you rotate the cone with respect to the shaft you can unlock the cone. It is apparent you need to rotate the cone until the three raised areas on the cone align with the three slots on the collar of the shaft, BUT, you cannot rotate the cone that far! It is also apparent the reason for this is a simple plastic key of some kind. Here is where the puzzle begins.
It is obvious when looking along the shaft at the pin there is a screwdriver slot in the pin. (At the time I did not know it was a pin.) One would guess, rotate the pin 180 degrees and somehow magically the cone itself would "unlock" and rotate fully to the unlock position, but no, that does not do it. What an idiot like myself should observe is the hole the pin is in is slightly "D" shaped. So now that you have rotated the pin, hopefully to the right orientation, you can slip a thin screwdriver in the slot "above" the pin and pry the pin backwards as it now will easily slip through the "D" shaped hole.
I show the pin removed so you can see it is a pin. All that is required is the pin be retracted as in the left hand picture. Remember later when reassembling the shaft cone to push this pin back in and "lock it" by rotating 180 degrees with a screwdriver. This pin could easily fall out! Imaging trying to replace a drive shaft shear bolt in the field. I am glad I had to figure this out now.
With the "lock pin" retracted you can now fully rotate the shaft cone to align the three slots with the white collar tabs projecting out of the shaft.
shown in the fully unlocked position, the white tabs aligned with the shaft cone
slots. You must have extended the PTO shaft so there will be
room to slide the yellow collar and shaft cone together down the body of the
shaft. Now on to the next mystery, reassembly!
Reassembling the shaft.
I figured since I was working on this puzzle in my workshop I ought to at least try to reassemble the shaft for practice before I try to attach it to the implement (post hole digger gear box). So I should be able to reverse the order of things and start by sliding the shaft collar and cone back up over the white plastic tabs on the PTO shaft alignment collar.
But no, there is another problem. The weight of the shaft is spreading the white shaft alignment collar apart. So far that the white collar is not engaging in the slots in the shaft itself anymore. So to reassemble the shaft I stood it vertically on end, squeezing the white collar together and into the shaft slots and now I can slide the yellow shaft cone and collar back into place! This could be fairly tough in the field where you must work with the shaft nearly horizontal. Obviously you can remove the shaft at the PTO end as well (more work!).
One more trick, locking the PTO Cone
With the shaft cone slid back up over the shaft body all I have to do is twist the shaft cone to lock it up. But what about the locking pin, HEY, it will not push back in. Yet another PTO shaft tip!
yellow PTO shaft cone and collar have what looks like an access hole, perhaps
for greasing the U joint. (Not in my case because the grease fittings face
the other way!). Well it probably is an access port, but it is also an
alignment aid too. When you rotate the shaft cone to a position where the two
holes align perfectly you may then slide the "lock pin" back into its locking position, NOT forgetting to then rotate the "D" of the pin 180 degrees so
the pin will not fall out.
Do not forget the PTO shaft grease fittings.
You can see the grease fitting on the yellow collar (to the right) in the photo above. You must grease these fitting periodically on both ends of the shaft. Sometimes there is plastic mold flashing that might block this grease fitting opening. Now is the best time to clean this up and verify the shaft is greased, mine was.
While your at it, check the shaft "U" joint grease.
There is always a chance they shipped the "U" joints dry. And they might not have lubed the shaft itself!
And a little dab of grease on the PTO shaft splines.
I did put a small dab of good grease on the PTO shaft splines, BUT, when I went to install the shaft I ran into yet another problem!
When I tried to slide the PTO shaft onto the tractor's PTO splined shaft it would only slide on halfway. I looked inside the collar, there was a machining tailing stuck in shaft locking sliding pin. Some needle nose pliers, and this came out easily. It was a sharp little gotcha too, had I stuck my finger in there the wrong way. All in all, I probably spent 8 hours on this PTO shaft (well including the photos!). This article took additional time.
Hooray, the PTO shaft disassembled and reassembled!
There is yet another tip for this Eurocardan PTO shaft involving safely mounting it on the gear box of the auger, yet another article. I hope these tips helped with your PTO shaft adventures.
by Bob Matheson