Kubota mower deck RC60-71B, the gear box oil leaked out

I need to pull the gearbox on my RC60-71H, which has a different gear box (70723-33110) from the RC60-71B in this post. Is removal the same?

I can't tell from the parts drawings if the shaft stays with the deck and the lower spindle housing like the RC60-71B (original post), or whether it comes out with the gearbox.

Thanks in advance for any assistance with this. I don't mean to hijack this thread but I thought it made more sense to collect the information under one heading.

BTW, I'm new here, good forum.

Here is the RC60-71H gearbox parts diagram:

OK, starting to feel a bit like I'm talking to myself but I'm going to post this in case it is useful to someone else. I got the gear box off. The shaft stays with the gearbox on the RC60-71H. First, take off the blade and associated washers. Then remove the circlip and the splined boss on the shaft. On mine the circlip was missing and the boss would not pull off. The next step is to remove the four bolts holding the gearbox on. Having done that, I was able to encourage the shaft and gearbox upward (block of wood and large hammer) driving the shaft up through the boss, at which point the gear box was off. It goes now to the dealer to have the bearings and seals replaced. I feel confident I could do that but they said it is just about one hour labor plus parts and I think it would take me a few hours at least and probably multiple trips for parts, tools (I would need large circlip pliers for this job) and supplies. And it will be good to develop a relationship with the local dealer.

I'll let you all know how it goes.

Yeah sometimes its just easyer and better to let somebody else do it that has done it before and has all the right tools,, even if it costs ya a couple of bucks

Project completed. Cost to have the dealer replace all the bearings in the gearbox and refill with oil was $139. While the gearbox was off I had a local welding shop do major reconstructive surgery on the swiss-cheese portions of the deck. They also primed it, cost $150. So, about $300 total (add $4 for a can of orange spray paint from WalMart and a few bucks for miscellaneous parts) and I'm back in business. I think this was a good way to do it, although in retrospect it might have made sense to go the extra $25 and get a new belt, then keep the old one as a spare.

Here is a "before" picture showing some of the problem:



Here are a couple of "after" shots:




I'd say it looks a bit better in the pictures than in person, but I think it will serve me well for a while longer. And now I need to catch up with the mowing. Fortunately I was able to keep up with the small stuff with my old Murray riding mower, but the bigger fields are calling to me.

One thing about it, that $300 is about a third of the cost for a cheap rider at Walmart. Your Kubota will last five times as long, with minimal maintenance. Bigger decks tend to make more even cuts also.

I am glad that my Woods deck has a belt drive vice a gearbox located under the tractor.

Robert

do you know where to get a new cheap gearbox at for a ZG20 kubota

PJC said:

I have a Kubota mower deck RC60-71B, the gear box oil leaked out and I need a top bearing (first one to overheat) and the oil seal at the bottom of the gear box (where the oil leaked out). I have removed the top bearing no problem, but I can't tell just what to do next to remove the lower bearing(?) to get to the oil seal. Can anyone help me with a short step-by-step explanation?

Click to expand...

Just replacing the bearings and seals will correct SOME of the out-of-balance play and vibration; but not all of it. The gearbox input shaft is very poorly-designed: supported by two 6205 [25x52x15] ball bearings, that are mounted virtually back-to-back. There is only 9/16" separation between them; so their resistance to sideways forces is minimal.

And those sideways forces can be considerable, since the PTO shaft typically operated at an angle about 15 degrees, in the case of my mower. So the bearings wear out quickly, and the resultant play wrecks the seals. Then the oil runs out; and the gearbox seizes. LOVELY . . . .

UPGRADES
1: Make sure the bearings you fit are close-tolerance: at least ABEC-3; preferably ABEC-5. And close fit as well: CM or CN, rather than the usual C3 [loose fit]. That will help - for a time.
2: Replace the ball bearings with cylindrical roller bearings: flanged NJ205 bearings are 25x52x15, so will fit right in. Limited resistance to axial thrust; but much higher sideways resistance.
3: Do away with the oil seal, and replace it with ANOTHER bearing, with its own oil seals. That's a 6205 2RS. That means leaving out the internal circlip, drilling and tapping 5/32" holes around the end face of the gearbox housing casting [I drill 6; you could go to 8]. Making up a clamp ring-plate to bolt round the shaft and onto the casting end. Using that to clamp and hold in the outer of the TWO bearings. If you want, you could then make the inner of the two bearings an NJ205 roller, for more strength - since the two ball bearings will take care of end thrust.
Finally, if you want to back up the built-in seals in the 6205 2RS, you can take a standard 25x52x10 oilseal, grind off the sidewalls [leaving just the flat disc] and install that under the clamp plate as an additional seal.
4: Carry out the same gearbox housing modification as [3] above. But, in place of an extra bearing replace BOTH ball bearings with Taper Roller bearings. The 30205 is 25x52x16.25 so, to get the gear wheel properly positioned, you have to machine 1.25mm off the inner and outer shells of the inside bearing. If you take a wider 25x52x22 taper roller for the outer bearing, and add a 10mm oilseal, that will protrude from the housing, and you use the ring clamp frame to apply the necessary preload - through the oilseal - for the taper rollers.

Four solutions, in rough order of effort needed, and resulting strength.

But God knows why Kubota made such a crappy design in the first place . . . .

spanner48, That description is way over my head but very thorough. So, with that description, if I were to take my gear case to a machine shop, they could build it?

WoW, thats a lot of bearings !! my RC 72 bearings lasted 9 years greased all the time, cut a awful lot of grass ,, the dam deck rotted out , never could get help to do their job right. PS the bearings are still good !!!

I have a B7100 with the RC60-71B mid mount deck. I too am now having this problem, oil leaked out and my top bearing seized up. I have the top bearing out and am about to remove the gear box housing to access the lower oil seal - but I'm having a very difficult time finding parts online specifically for the 71B deck. Finding plenty for the R60-72 and others but not the 71B? Any suggestions where to go to find the right bearing and oil seal?

Thanks.

Are the bearings anything special? Had a bearing go out on an old Woods belly mower. I just went to Napa found a generic one that was the correct inside and outside diameters. My guess is the seals aren't that much different either.

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PJC said:

Answer: remove (4) gear box mounting bolts #310 and the gear box just lifts straight up, and the lower bearing and oil seal comes up and out with the gear box; and the pulley and pulley drive shaft #250 remains in place. You may need to pry slightly between the bottom of the gear box and the top of the pulley to break the slight adhesion between the lower bearing and oil seal, and the pulley drive shaft.

Click to expand...

I'm needing to do this on my RC72-B mower (same gearbox design from what I can tell) and don't see how this is possible with snap ring #150 still in place. I'll report back, hopefully later today