What could cause an F2100 to start eating clutch disks?

[the mean fish]

I'm about to start tearing down a 4x4 F2100 that I picked up from a buddy who put 3 clutches in it in a matter of a couple months then gave up and parked it in his back yard which is where it's sat for the last year or so. After stilling for all that time it starts and runs great and all the hydraulics work great too. The clutch went out and he didn't want to mess with it again so he bought something else to mow with and parked this thing.

He kept all of the old clutch disks and parts that he took off of it and they all look exactly the same, great looking clutch surface material but all of the splines are ripped out leaving the center disconnected from the clutch outer ring. This last time he replaced it he also replaced the pressure plate and both bearings, the clutch lasted less than 40 hours. The other 2 lasted a little longer but both under 100 hours while the original clutch had almost 2000 hours on it before it broke out the center. He thought about having someone rebuild one of the clutches with something stronger but to me that just means the problem will get pushed somewhere else unless Kubota just had a run of bad clutches or something.

I'm looking at the service manual and I can't for the life of me figure out what could have gone wrong causing it to do this. Can something be out of alignment or bent and cause such a problem? Every time he's broken a clutch disk it happened while mowing on flat smooth ground, never while shifting or anything like that.

This thing has the wide deck up front, could that be putting more stress on the clutch than a smaller deck would? Here are a couple pictures of this beat for reference, I have my work ahead of me.

 

[kuboman]

I'm about to start tearing down a 4x4 F2100 that I picked up from a buddy who put 3 clutches in it in a matter of a couple months then gave up and parked it in his back yard which is where it's sat for the last year or so. After stilling for all that time it starts and runs great and all the hydraulics work great too. The clutch went out and he didn't want to mess with it again so he bought something else to mow with and parked this thing.

He kept all of the old clutch disks and parts that he took off of it and they all look exactly the same, great looking clutch surface material but all of the splines are ripped out leaving the center disconnected from the clutch outer ring. This last time he replaced it he also replaced the pressure plate and both bearings, the clutch lasted less than 40 hours. The other 2 lasted a little longer but both under 100 hours while the original clutch had almost 2000 hours on it before it broke out the center. He thought about having someone rebuild one of the clutches with something stronger but to me that just means the problem will get pushed somewhere else unless Kubota just had a run of bad clutches or something.

I'm looking at the service manual and I can't for the life of me figure out what could have gone wrong causing it to do this. Can something be out of alignment or bent and cause such a problem? Every time he's broken a clutch disk it happened while mowing on flat smooth ground, never while shifting or anything like that.

This thing has the wide deck up front, could that be putting more stress on the clutch than a smaller deck would? Here are a couple pictures of this beat for reference, I have my work ahead of me.

I would wonder if a bearing or something has gone to put the alignment of various shafts out. Not sure of the construction of the unit but something is out of alignment.

 

[the mean fish]

I would wonder if a bearing or something has gone to put the alignment of various shafts out. Not sure of the construction of the unit but something is out of alignment.

I'm thinking along the same lines, I haven't split it yet to take a look inside so I'm not sure what I'll find but I suspect something is either wrong or worn out in there.

 

[the mean fish]

Could the flywheel surface be so bad that it could cause this problem? It seems like the machine vibrates a lot more than I would expect it to when running, if the flywheel needed to be machined back true then that could be causing the vibration and causing the clutch disks to break away from the clutch center right?

 

[kuboman]

Could the flywheel surface be so bad that it could cause this problem? It seems like the machine vibrates a lot more than I would expect it to when running, if the flywheel needed to be machined back true then that could be causing the vibration and causing the clutch disks to break away from the clutch center right?

I must admit ignorance but is the unit not hydrostatic? If so then the clutch you are referring to is the pto clutch...correct?

 

[the mean fish]

I must admit ignorance but is the unit not hydrostatic? If so then the clutch you are referring to is the pto clutch...correct?

It is hydrostatic but there has to be a clutch in there somewhere right? With this clutch out the tractor won't move or spin the blades...

 

[kuboman]

It is hydrostatic but there has to be a clutch in there somewhere right? With this clutch out the tractor won't move or spin the blades...

I cannot help with this one but I would think it is like most other front mount mowers where the engine is coupled direct with a drive shaft to the hydro unit. But, I do not know. Someone else will have to step in here.

 

[eserv]

The F2100 does have a conventional clutch as do most "B" series tractors with Hydro drive. (also ALL "L" series) as for why it's eating disc splines, my guess would be misalignment as in something bent or maybe someone lost the dowel pins when they split the tractor to replace the first clutch?

 

[kuboman]

The F2100 does have a conventional clutch as do most "B" series tractors with Hydro drive. (also ALL "L" series) as for why it's eating disc splines, my guess would be misalignment as in something bent or maybe someone lost the dowel pins when they split the tractor to replace the first clutch?

Well there ya go!! Learn something every day. Should be quite obvious to spot when it is apart.
Why would Kubota bother with a clutch?? Is it to engage the deck drive instead of a hydrualic clutch

 

[eserv]

They don't have a Hydraulic pto clutch, the foot clutch serves that purpose. I kinda prefer the system, it allows precise feathering of the pto, a nice feature when starting large mower decks! The B3030 doesn't have a foot clutch either, nor do the newer Fxx60 series front mout mowers. I think it will be phased out of all the "Bs" in time.
Ed

 

[kuboman]

They don't have a Hydraulic pto clutch, the foot clutch serves that purpose. I kinda prefer the system, it allows precise feathering of the pto, a nice feature when starting large mower decks! The B3030 doesn't have a foot clutch either, nor do the newer Fxx60 series front mout mowers. I think it will be phased out of all the "Bs" in time.
Ed

I agree on the feathering part but it does seem to complicate an otherwise simple system. Hydraulic clutches are generally very trouble free and can be made to feather with very simple valving.

 

[the mean fish]

Thanks for all the info guys, I'm learning more about this thing every day. I'm getting real close to the point where I can tear it apart.

 

[uncle jed]

just checking in. did you get it apart, and what did you find? i have one of the parts manuals on cd if you need it i could send you a copy. PM if you need on . uncle jed

 

[dtruex]

I don't know anything about this beast but I've seen auto engines do this after loosing a crankshaft thrust bearing. This allows the crankshaft to move back and forth and causes the disk to break as it tries to slide in and out on the transmission input shaft. It will also make the engine vibrate. It's easy to check by putting a pry bar under the front crank pulley and pulling forward, then putting it under the flywheel and pushing back. Most engines only have a few thousands of an inch clearance.

 

[traildust]

I don't know anything about this beast but I've seen auto engines do this after loosing a crankshaft thrust bearing. This allows the crankshaft to move back and forth and causes the disk to break as it tries to slide in and out on the transmission input shaft. It will also make the engine vibrate. It's easy to check by putting a pry bar under the front crank pulley and pulling forward, then putting it under the flywheel and pushing back. Most engines only have a few thousands of an inch clearance.

That's some really great information, thank you for sharing

 

[the mean fish]

just checking in. did you get it apart, and what did you find? i have one of the parts manuals on cd if you need it i could send you a copy. PM if you need on . uncle jed

Jed, thanks for the offer. I may be in touch soon, I have the service manual and I think the parts list but it's on paper so the CD may be a lot nicer. I haven't torn it down just yet, I'm moving on Jan 3rd to the property I bought it to cut and I don't have room to store it until then.

 

[the mean fish]

I don't know anything about this beast but I've seen auto engines do this after loosing a crankshaft thrust bearing. This allows the crankshaft to move back and forth and causes the disk to break as it tries to slide in and out on the transmission input shaft. It will also make the engine vibrate. It's easy to check by putting a pry bar under the front crank pulley and pulling forward, then putting it under the flywheel and pushing back. Most engines only have a few thousands of an inch clearance.

Thanks for the info, I hadn't thought about that at all. I'll check it when I get it taken apart.

 

[the mean fish]

Just a little update, I finally got this tractor home so I can start getting it rolling again. I found a guy on eBay parting out an F2100 so I picked up a few extra hard hoses and parts that I wanted to replace.

So far this is what I know I need

• Clutch Disk w/bearings
• Battery

 

[mud from mo]

I have had clutch problems with my b8200. The shaft had too much play in the pilot bushing, it created too much noise when the clutch was not depressed. I replaced the bushing twice with the Kubota part.The pilot bushing that Kubota lists seems to have to large of a bore. I had a machinist measure my shaft were it rides in the pilot bushing and bore my own pilot bushing. I haven't had problems since.

 

[the mean fish]

I actually made some good progress today on the old girl. I took the hood off and got it out of the way. I cleaned out all the grass and weeds that had grown up through the frame and replaced the 2 main battery cables which were trashed. I put a brand new Interstate battery on it and it started up like it was still on the showroom floor. She purrs like a kitten and once I let her get warmed up I saw that the temp and fuel gauges still work perfect. The tach doesn't work nor does the hour meter which is stopped dead at 1900 hours.

The deck lift hydraulics work perfectly as well as the power steering. I talked to my local Kubota dealer/service guys and by using the serial number they pulled up a service bulletin which calls for a clutch upgrade kit. It replaces a coupler and propeller shaft along with a few other parts and it's supposed to improve clutch and bearing life in the F2100 units.

I was originally thinking about doing the clutch replacement myself but given the service bulletin and the amount of time it'll take I'm considering letting them get it right the first time. I'll eventually replace a lot of the wiring, fix a lot of paint and stuff like that but I don't want to dump any cash into it until I know the clutch problem is fixed. The previous owner had trouble with the ignition switch so he replaced the engine kill function with a push button which needs to be replaced along with a bunch of other little things.