Hello, everyone. On my 7 year old Z726 60inch zeroturn, I heard an awful racket coming from the center of the deck when the blades were on. When I took the blades off, my impact was thumping the whole time on the strongest setting. The threads on the bolt and spindle were shot to hell. I replaced the spindle but the noise is still there. Tomorrow I'm taking everything back and inspecting the bearings. This is new to me because I don't have a lot of experience in mower bearings like this. Can someone please advise me on procedures, and where these bearings will be? Any extra advice or tricks would be greatly appreciated! Thanks!
Bearing, Help!
- Thread starter RCopple
- Start date
whitetiger
Moderator
Staff member
Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
With the deck belt removed, spin each blade spindle and idler pulley one at a time by hand. This will tell you where the noise is coming from.
There will often be two bearings per spindle. One about where it goes through the deck, another a bit higher. There will be a workshop manual that tells you how to dismantle it. It's not incredibly hard, but not incredibly easy either. Generally you detach all the stuff around it, then have to press the bearings off. You want to know that you're doing it right - you don't want to go trying to press the bearing off and then discover there's still something holding it on - then you wreck something.
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Two bearings (30) per spindle with a spacer (40) in between. Bottom bearing retained in hub by internal snap ring (60).
Dan
Kubota Tractor RCK60P-725Z(Z726XKW-2) T00703 Pulley Holder/Blade (Center) | Kubota Tractor
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TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
k
BTW - looks like the Kubota bearing is a good old shielded 6206. (Made in China)
Dan
Is this machine new to you? Just curious how a machine gets the blade nuts that tight. When was the last time the blades were serviced?
Looks like you have all the pointers you need, just take pictures as you go if you are unsure of process.
Looks like you have all the pointers you need, just take pictures as you go if you are unsure of process.
Blade nuts can be easily removed by putting a piece of 2x4 onto the blade and jamming it on the deck to keep the blade from turning. Use an electric impact gun on the mower blade to loosen it.
the bearings are 6206-zz
they're available elsewhere, but generally speaking kubota is less expensive than most everywhere else (unless you buy them in bulk).
You can also use 6206-2RS which is two rubber seals rather than metal shielded. The shielded bearings do a little better with high shaft speeds than RS, but RS protects against dust/dirt a little better.
koyo has a neat little calculator on their site (IIRC) that deals with expected lifespan given the rpm and loading. Worth a look if you have the data. Remembering, radial ball bearings don't do all that well with axial loads (side loads). You'll see this if you look up the specs. And rotary mowers do in fact load the bearings significantly in the axial direction. Woods used a lot of tapered roller bearings in their finish mowers, and they were rare to fail-unless owner neglected greasing them. Power hungry though. Always a trade-off.
Koyo has lasted longer than the OEM bearings, but the OEM stuff is dirt cheap and I don't mind buying them for that reason-I actually keep 9 on hand at all times, buying from the dealer. My dad used to be a dealer for Fafnir bearings-which was a division of Textron (he had a home-based bearing shop)-until they sold out to Torrington in 1988 (?). Torrington sold to Timken as I remember but I don't know what year that took place, we moved in 1989 and left most of that stuff behind.
they're available elsewhere, but generally speaking kubota is less expensive than most everywhere else (unless you buy them in bulk).
You can also use 6206-2RS which is two rubber seals rather than metal shielded. The shielded bearings do a little better with high shaft speeds than RS, but RS protects against dust/dirt a little better.
koyo has a neat little calculator on their site (IIRC) that deals with expected lifespan given the rpm and loading. Worth a look if you have the data. Remembering, radial ball bearings don't do all that well with axial loads (side loads). You'll see this if you look up the specs. And rotary mowers do in fact load the bearings significantly in the axial direction. Woods used a lot of tapered roller bearings in their finish mowers, and they were rare to fail-unless owner neglected greasing them. Power hungry though. Always a trade-off.
Koyo has lasted longer than the OEM bearings, but the OEM stuff is dirt cheap and I don't mind buying them for that reason-I actually keep 9 on hand at all times, buying from the dealer. My dad used to be a dealer for Fafnir bearings-which was a division of Textron (he had a home-based bearing shop)-until they sold out to Torrington in 1988 (?). Torrington sold to Timken as I remember but I don't know what year that took place, we moved in 1989 and left most of that stuff behind.
