Zen-Noh ZB5000- Extracting the Front 4wd Drive Shaft Universal Joint

AussieMate

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Equipment
Zen-Noh ZB5000 (Kubota)
Aug 6, 2010
3
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Wamuran, Australia
Zen-Noh ZB5000- This is a description of how I extracted the front drive (4wd output shaft) Universal Joint without having to split the tractor at the gearbox. At least you get to lay on your back for the whole procedure.

Step 1- I drilled a hole in the underside of the chassis box rail as close as possible to the centreline of the small split roll pin, that secures the yoke to the front drive output shaft (See photo 1).Make the hole just big enough to fit a drift or Pin punch through. This gives a much straighter angle to the pin, because it's impossible to punch the pin out from the normal access hole, the angle is just too radical ( See photo 2). I squirted some WD40 or similar lubricant into the roll pin hole and let it soak for a few minutes, then lay on my back with hammer and 3-3.5mm Diameter Pin punch and give the pin many sharp hits with the punch until it starts to push through. I used many short sharp hard hits rather than huge big hits, you don’t want to break anything. I cut a 3mm diameter piece of bendable wire to knock the pin through the last few mm as the angle was still not quite perfectly straight and the Pin punch wouldn't quite punch all the way through.

Step 2- Now using a 5.5mm drift or pin punch, I punched through the larger split roll pin that secures the other Uni' joint yoke to the long drive shaft that angles down to the front axle assembly (See photo 3). I can access this through the normal access hole. Use many short sharp hard hits rather than huge big hits, you don’t want to break anything. Photo 4 shows the shaft rotated 180 degrees and the large pin almost fully knocked out.

Step 3- After both roll pins are knocked out, just use a flat screwdriver and push the Uni' yoke off the small front drive output shaft at the gearbox (See photo 5) and then do the same to lever the other yoke off the long drive shaft that angles down to the front axle assembly (See photos 6 to 9 in my 2nd forum post- Limit of 5 pics per post!). I held the shaft with a pair of pliers, as it does slide up and down a bit.

Step 4- Extract the whole uni' joint assembly through the normal access hole (see photo 7) and then I can take the whole uni' assembly (see photo 8) and put it in a vice and disassemble the unit joint and replace it with a new one.

Step 5- Importantly I also liberally coated the hole that I drilled in the underside of the chassis rail, with some primer undercoat and then some KILLRUST paint or similar antirust coating to ensure the hole does not become rusted in the future.

Assembly will be the reverse of this procedure and I expect that knocking the roll pins back in will be tricky but not impossible.
Photo 9 shows the pin punches and 3mm wire I used to knock out the split roll pins.
Note, this description is not an approved Zen-Noh or Kubota procedure and I am not suggesting that you should do the same as I did.
Rather it is just a description of how I decided to tackle a problem on my own, rather than splitting the tractor by myself. I take no responsibility for any damage to your tractor or injury that you may incur if you try this procedure.
 

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AussieMate

New member

Equipment
Zen-Noh ZB5000 (Kubota)
Aug 6, 2010
3
0
0
Wamuran, Australia
Part 2 Assembling the Front 4wd Drive Shaft Universal Joint
I managed to buy a new Uni joint at a nearby bearing supplies shop (BSC Motion Technology, Caboolture, QLD, for any one in Australia Ph (07) 54956266). They had them in stock.I then dismantled the old uni joint from the yokes and replaced it with the new uni joint.
Lots of info on the net if you dont know how to do that procedure.

Step 1 - I lightly hammered the 2 split roll pins (large & Small) into their respective holes in the Uni Joint yokes, just far enough to keep them in place. Dont let them protrude into the inner shaft cavity (see photo 10).

Step 2 - Now laying under the tractor I pushed the uni joint assembly up in through the inspection hole and slipped the large pin yoke onto the front drive shaft spline lining up the roll pin hole. Then rotated that shaft about 90 degrees by turning the front wheel, so I could line up the downward facing small hole on the gearbox drive shaft with the small hole in the other yoke (see photo 11).

Step 3 - I punched the large roll pin in first using a pair of multigrips to hold the front drive shaft (see photo 12), as I could access it easily through the inspection opening. Then I punched the small roll pin in by poking the pin punch through the hole I had previously drilled next to the inspection opening (see photo 13) and lightly hammering that one home also. Seems to be easier to use a pin punch that is slightly larger than the pin when drifting them back in. Photo 14 shows the job finished, easy !!
 

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