Kubota zd326 rear discharge deck

DanBX

New member

Equipment
BX1830, ZD326
Oct 7, 2014
6
0
1
Harrodsburg,Ky, USA
Hello, I bought a Kubota zd326 with a rear discharge 60” deck. It is used and there were things I expected to have to do to it, however I have one problem that I can not solve.
The deck belt broke so I replaced the idler pulley along with bushings, checked bearing noise, any looseness, ect. All looked ok but I noticed the bottom seal on the gearbox leaked.
New belt. Broke new belt about the third time mowing.
I decided to rebuild the gearbox and center spindle.
New belt #2.
Broke belt #2 and noticed the idler pulley spring launched out left side of deck about five feet.
The belts are about $85 so I would appreciate anything I can check if anyone has run into this with a zero turn mower.
One question; the zd326 has a more common deck that is 60” with side discharge. My question is, are the belts part numbers different for the side discharge vs the rear discharge deck ?
The one thing I noticed about the deck belt was it appeared to wobble a lot. It rubbed the top of the deck leaving a black streak wherever it touched.
Thank you
 

100 td

Active member

Equipment
B21TLB (B21, TL421 & BT751) Toyota SDK4 T116 Bobcat
Aug 29, 2015
1,776
8
38
ɹǝpunuʍop
The one thing I noticed about the deck belt was it appeared to wobble a lot. It rubbed the top of the deck leaving a black streak wherever it touched.
Thank you
Bad batch of belts?
I suspect something is wrong, belt isn't tight enough, and/or not aligned correctly, and/or a pulley or spindle is out of round or incorrect belt. Recheck position of tensioner, ensure that it can freely move past the point of maximum tension, set it up, mark it's position, take belt off a pulley and ensure tensioner can easily go past the marked position(tighter). Spin each spindle and pulley and check for runout or resistance. Check spring for stretch.

Also check multi groove pulleys for cleanliness, and when you install the belt, manually fit the belt to each pulley ensuring correct centering of the belt in the grooves.
Grease spindles and tensioner assembly.

Go to https://apps.kubotausa.com/illustrated-parts/ and check you have the correct belt.
YMMV.
Edit: I'm guessing you have a RCK60R-331Z deck
 
Last edited:

DanBX

New member

Equipment
BX1830, ZD326
Oct 7, 2014
6
0
1
Harrodsburg,Ky, USA
Hello 100 td,
Appreciate the advice and yes, the deck is the RCK60R-331Z !
I am going to just complete the rebuild at this point. Parts ordered today and will be here by Tuesday.
 

mikester

Well-known member

Equipment
M59 TLB
Oct 21, 2017
3,125
1,609
113
Canada
www.divergentstuff.ca
Are you routing the belt correctly? Is it rubbing anywhere?

Last time I changed my belt I accidentally put it on the wrong side of a 1/4" pin which sticks out of the mower deck located somewhere underneath the operator deck - hard to see - caused a lot of belt vibration when I turned on the pto the first time.
 

DanBX

New member

Equipment
BX1830, ZD326
Oct 7, 2014
6
0
1
Harrodsburg,Ky, USA
Hello Mikester !

Yes, on the belt. This last time I had the deck off the mower and the belt was the final thing before setting the deck back on the ground and sliding it under the mower. I checked for location and tightness.
This is my first zero turn mower and truthfully don’t drive it well yet. But I have had my BX Kubota for fourteen years and am familiar with the importance of the belt.
Thank you for trying to help me and noticing the vibration of the belt. I will be better prepared when I put the new parts on next week. Hopefully have a better
Time with the deck.
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
4,807
1,575
113
Mid, South, USA
Those belts are rarely replaced at the shop. I think maybe 1 a year. I only stock one of them because it's not a fast moving part. Kommander 100 series? Another story...

Anyway...

Something's going on. Either something is out of alignment, something's shock loading the belt, or whatever. Rubbing a guide pin maybe (have seen that a time or two), have also seen one rubbing the gearbox support because the support was bent.

Is yours a pro deck? I am assuming it is. (RCK60R-331Z?)

Vibration....can also cause problems. Sources are out of balance/worn blades, deck gearbox out of kilter, gearbox drive pulley key and/or shaft worn allowing the pulley to run untrue, idler issues, and the two spindle pulleys having issues, such as bent shaft, etc. #1 cause (at the shop)? Debris in the pulley groove. Causes belt to vibrate, which can hurt it prematurely. Lastly, using it for a rock crusher will hurt parts including but not limited to the belt. I realize not everyone uses their mower hard but I know of people who do....and they're the ones who gripe about "longevity"....when I said rock crusher, I meant it....because I've got customers who use them that way. Rock sticking up in the yard? Mulch it!! :eek: Tree roots? Fair game...you get the idea...

As said those double groove belts are pretty close to bulletproof...so you're going to have to look the deck and all of it's componentry over VERY closely to find the cause. My neighbor (well if you call him that....a mile away), has a 331 side discharge, has the original belt on it, 1900 hours. I know because I do his maintenance and repairs....and have been doing it since it was purchased brand new from the dealer I was working at. The ZG200's also use the same design of belt, and I see those with tons of hours....and sometimes the double vee belt is just two belts and the backing is gone. They last a LONG time, so this is also an indication that there's something weird going on with yours.

When I've got one at the shop...don't matter if it's double vee pulley or a 100 Kommander, without a belt to inspect, it's harder to diagnose. Lots of times you can look at the belt and inspect it's wear or breakage to help diagnose what the cause is. So without seeing your belt, all we can do is give you guidance on where to look.
 

DanBX

New member

Equipment
BX1830, ZD326
Oct 7, 2014
6
0
1
Harrodsburg,Ky, USA
Hello Lugbolt,
I appreciate the motivation !
I get the final parts, and new belt tomorrow.
Don’t know if I have the word power but will give an update in a few days.
Thank you
 

DanBX

New member

Equipment
BX1830, ZD326
Oct 7, 2014
6
0
1
Harrodsburg,Ky, USA
All my parts didn’t come in so I have to wait until next week. I gone over the center pulley and notice it is the only questionable movement I have.
The center pulley “wobbles” a bit on the shaft. The gearbox bearings and seals are all new. Nothing is bent.
I have tried to attach the parts schematic. “1” I have labeled, is the shaft. The shaft will move in to the gearbox, about 1/16 of an inch.
“2” is the center pulley that I can “wobble” on the shaft .
I checked the center pulley on my BX dearbox. There is no “wobble”.
Has anyone run into this ?
It does not look like the shaft is bent or otherwise damaged. I am guessing the center pulley is damaged.
 

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