Kubota M5091 Poor Clutch Action

[Grizzo]

Hi. I have a Kubota M5091. I'm liking the tractor except for the clutch performance. The take up when releasing the pedal is too fast/ sudden. Because of this, it is very difficult to take off smoothly without jerking forward like you are just learning to drive a manual vehicle.
This tractor has a wet clutch. The free play and pedal range are adjusted properly.
Is there any adjustments or changes that can be made to make the clutch more user friendly?

Thanks.

 

[SidecarFlip]

You should be using the hydraulic shuttle lever to start and stop, not the clutch pedal. The clutch pedal don't link to a 'clutch'; anyway. It links the the same proportioning valve the shuttle lever links to.
Only time the 'clutch' pedal is used is when selecting a different gear.

Because it's a load sensing valve, it will engage abruptly when it senses a big load. Perfectly normal.

I think it's extremely user friendly. Certainly better that having to split a tractor to replace a dry clutch disk. Multiplate wet clutches hardly ever wear out. You can set the lock up pressure. There is an access port on the valve body that accepts a pressure gage but you need a liquid filled gage with a 2100 psi capacity and the special adapter to fit the valve body. My one shuttle tractor has 6000 meter hours on it, I borrowed my dealer's gage and adapter and the pressure was right on the spec so I didn't fiddle with it at all.

The valve body is on the left side of the transmission case, under the fender on an open station and on top the case in a cab tractor.

 

[Grizzo]

You should be using the hydraulic shuttle lever to start and stop, not the clutch pedal. The clutch pedal don't link to a 'clutch'; anyway. It links the the same proportioning valve the shuttle lever links to.
Only time the 'clutch' pedal is used is when selecting a different gear.

Because it's a load sensing valve, it will engage abruptly when it senses a big load. Perfectly normal.

I think it's extremely user friendly. Certainly better that having to split a tractor to replace a dry clutch disk. Multiplate wet clutches hardly ever wear out. You can set the lock up pressure. There is an access port on the valve body that accepts a pressure gage but you need a liquid filled gage with a 2100 psi capacity and the special adapter to fit the valve body. My one shuttle tractor has 6000 meter hours on it, I borrowed my dealer's gage and adapter and the pressure was right on the spec so I didn't fiddle with it at all.

The valve body is on the left side of the transmission case, under the fender on an open station and on top the case in a cab tractor.

Hi, thanks for the reply. I have to partly disagree with you that I should be using the shuttle control to start and stop. Yes it is practical to use it sometimes such as in open spaces, but in any kind of movements close to something or if you need small amounts or a slow movement you have to use the clutch to stop and start. Using the shuttle will not get you precisely enough to where you want to be and can be very dangerous as well. Plus, the shuttle does not take off as smooth as you sometimes need either. If you have the revs up, you need clutch control to take off smoothly.
Another example is say you are working an implement, traveling forward and you want to change to a higher or lower gear, you put the clutch in, stop, change gear, let the clutch out and take off again. Having to use the shuttle would mean taking the lever out of forward, stop, then the clutch to change gear, clutch out, then the lever again. Quicker and easier to just use the clutch only and leave the lever where it is.

The wet clutch is fantastic for it's durability for sure, but it is definitely not user friendly if its so difficult to take off without a great deal of abruptness.

Anyway, would setting/ changing the lock up pressure make the clutch any easier to take off smoothly?

 

[PoTreeBoy]

I'm going to ask the inevitable $64 question - what fluid are you running?

 

[SidecarFlip]

I'm going to ask the inevitable $64 question - what fluid are you running?

Shouldn't matter at all other than a hydraulic fluid rated at the proper API recommendation. It's a gear drive transmission, not a hydrostat.

 

[SidecarFlip]

Anyway, would setting/ changing the lock up pressure make the clutch any easier to take off smoothly?

Maybe, maybe not. Lock up engagement is controlled by the proportioning valve. reducing the lock up pressure below factory spec will accelerate the wear on the wet clutch plates and you don't ever want to replace them. While you can 'see' the wet pack if you remove the rear pto cover, you cannot access it without splitting the tractor as it's located in front of the differential gears and axles.

If it's too abrupt, try dropping down a gear or 2. I would never consider any other transmission and clutch assembly. You'll also find that if your engine rpm is higher the engagement of the pack is slower because the valve is adjusting to load. If I was to purchase a new unit, would be a CVT transmission but even with a CVT, the wet pack is still there.

My one tractor has over 6000 meter hours on it and the other 2000 and neither have ever required any pressure adjustment and both work as new.

They are rats butt for loader work and constant directional changes where a dry clutch is constantly wearing the wet pack isn't.

I use my shuttle lever exclusively and never the foot clutch pedal except when changing the gearbox ratio's. Another nice thing about the wet pack is, half clutching a dry clutch will wear it out quickly. Half clutching a wet pack will wear it as well, but much, much slower and you can 'ride' the clutch without fear of eating up the throwout bearing because there isn't one. Nothing in the bellhousing except a damper plate that negates the shock load to the crankshaft from the transmission and they hardly ever wear out. The damper plate is an inner driven plate and an outer drive plate with coil springs to absorb the shock load (from directional changes).

 

[Grizzo]

I'm going to ask the inevitable $64 question - what fluid are you running?

What the factory put in from new. Tractor is under 50 hours.

 

[Russell King]

Can you visit the dealer and drive a similar tractor and see if you find it operates the same? If it does then that indicates your tractor is “normal “, if large differences between operating characteristics then have the dealer evaluate your tractor versus the test tractor.

 

[SidecarFlip]

If it's that new, even in Oz it will have SUDT in the gearcase.

 

[Grizzo]

Can you visit the dealer and drive a similar tractor and see if you find it operates the same? If it does then that indicates your tractor is “normal “, if large differences between operating characteristics then have the dealer evaluate your tractor versus the test tractor.

Yes, I’m planning on doing that.
thanks.

 

[Thunder chicken]

Hi, thanks for the reply. I have to partly disagree with you that I should be using the shuttle control to start and stop. Yes it is practical to use it sometimes such as in open spaces, but in any kind of movements close to something or if you need small amounts or a slow movement you have to use the clutch to stop and start. Using the shuttle will not get you precisely enough to where you want to be and can be very dangerous as well. Plus, the shuttle does not take off as smooth as you sometimes need either. If you have the revs up, you need clutch control to take off smoothly.
Another example is say you are working an implement, traveling forward and you want to change to a higher or lower gear, you put the clutch in, stop, change gear, let the clutch out and take off again. Having to use the shuttle would mean taking the lever out of forward, stop, then the clutch to change gear, clutch out, then the lever again. Quicker and easier to just use the clutch only and leave the lever where it is.

The wet clutch is fantastic for it's durability for sure, but it is definitely not user friendly if its so difficult to take off without a great deal of m

Good day
You can shift gears using only the shuttle, no need to use the foot clutch pedal, or stop for that matter if you’re rolling along.
ive tried using the shuttle to shift on the road but it’s just not smooth enough like you mention. However your foot clutch pedal should able u to feather it in and not be quite so abrupt. I do lots of loader work/pallets so ya kinda can’t be rammy! If the revs are up it’ll be a lot more jerky though ( like during a regen).
As a side note, my newer Tacoma has/had a hydraulic accumulator in the clutch line. Makes engagement more consistent they say..... takes away your feel more like it...

 

[hagrid]

As a side note, my newer Tacoma has/had a hydraulic accumulator in the clutch line. Makes engagement more consistent they say..... takes away your feel more like it...

There are kits to delete that accumulator.

 

[Thunder chicken]

There are kits to delete that accumulator.

Notice I said has/had?! A simple piece of brake line with the right ends, or simply drilling/dremel-ing out the accumulator itself 2nd Best mod to truck, (best was adding a relay to engage low range while in 2wd)

 

[hagrid]

Ahh...

Very well, then.