Grading Tightening Kubota Mower Blade Bolts

[m7040]

On my ZD 331 it has the same problem. I would put a large wrench on top of the two outside spindles to hold it from rotating and use a torque wrench on the blade bolts. On the center one under the gearbox I would insert a large screw driver in the Ujoint of the drive shaft to hold it. Used to use an air impact wrench but sheared a bolt in the process.
Today I use Milwaukee impact that has setting for torque and number 2 setting corresponds to the Kubota torque

 

[ROUSTABOUT]

Need some guidance from someone who knows what he or she is doing,

I have a BX2350 for which I just purchased a MMM, model RCK5423BX. With the deck I bought a mulching kit. When removing the standard blades I found that blocking the blade with a piece of wood while turning the blade bolt didn't work, so I had to hold the upper spindle nuts with another wrench. No big problem. The center blade bolt came loose with the block of wood trick---fortunately.

THE PROBLEM: When I installed the new blades I again used the second wrench on the upper nuts in order to be able to torque the blade bolts to specs. The wood block won't hold the center spindle, however. The whole pulley/spindle assembly rotates. Since the gearbox is on top of the center spindle, how does one go about holding that spindle? I notice there's a round rubber seal in the top of the gearbox which displays the MMM model number. Is there a spindle nut to grab onto if that seal is removed?

(It would've been REALLY nice had Kubota's instruction manual addressed this issue. Can't believe it hasn't come up before.)

Thanks for your assistance.

Bill

Why can't you hold the drive shaft from turning. I always used a piece of chain tied around the blade and the deck. Air wrench on the blade bolts. I worked at Kubota. Dealer has been there since 1944. Started out as a Ford dealership. I didn't ever replace the cup washers unless the owner asked for me to.

 

[WranglerX]

I have two riding mowers, and one requires blade bolt to be torqued to 110ft-lbs... I always use a 4x4 block and large "C" clamp to wood block in place to keep the blades from spinning (yes all three blades/spindles) and it has never failed me, if your wood block technique is failing you, you are doing it wrong....
Funny thing here is no one has mentioned clamping wood block in place, it would be interesting to me to see the instructions Kubota has written on how to use wood block...

 

[buckeyefarmer]

Block of wood and torque wrench. Or use impact with a proper torque stick.

 

[DK35vince]

Thanks to all who replied. Removing the nuts with an impact wrench is easy, but tightening them is another story. I've never seen an impact wrench whose actual torque was close enough to rated torque--just too many variables

I've been using an impact wrench to remove/install my mower blades for decades.
Takes minutes
Never an issue. (no wood block needed)

 

[Gem99ultra]

Why can't you hold the drive shaft from turning. I always used a piece of chain tied around the blade and the deck. Air wrench on the blade bolts. I worked at Kubota. Dealer has been there since 1944. Started out as a Ford dealership. I didn't ever replace the cup washers unless the owner asked for me to.

The cup washers give me total h*ll. Any problem with not putting them on?

 

[dadohead]

The cup washers give me total h*ll. Any problem with not putting them on?

Yes! The belleville washer transmits the clamp force from the blade bolt to the outer rim of the spindle so it can effectively drive the blade(s).

If the blade has just a round hole (not a star shaped mechanical driver) the install torque is not a big deal because the joint is self tightening. A few rattles from your impact will hold the blades well enough to stay on when the PTO is shut off and brakes engaged (5 second stop per ANSI). After mowing it just gets tighter...

 

[ROUSTABOUT]

The cup washers give me total h*ll. Any problem with not putting them on?

You need them to give clamping force on blade.

 

[zzvyb6]

On My JD deck, mulching blades are a bit thinner, so you need to add provided washers to get them tight. Otherwise, you run out of thread. Pretty close to tight, but no cigar.

 

[AndyMA]

On all my mowers I use my Milwaukee M18 impact, No blocks or chains required.

Andy