Clutch is stuck!

[Tim_D]

Anybody got any ideas for how to free a stuck clutch on a B20 Hydrostat? I took the dealers advice and parked it up against a tree, locked in 4WD-Low and popped the clutch a few times. Well the 4WD works! Dug some 6" ruts really quick! I understand the only sure way to cure this problem is to split the tractor in two for a clutch replacement. I don't want to do that until I have exhausted any/all potential trials to break the clutch free. Any suggestions would be appreciated.
Tim

 

[Henro]

Just for clarity...around here, popping the clutch means engaging it rapidly, which could not be done if the clutch was sticking...so I take it you mean you pushed the HST pedal quickly while keeping the clutch pedal depressed with your other foot, right? The goal being to try to break the clutch free. Important to keep the clutch pedal depressed when doing this...

One thought that came to mind would be to use the tractor doing some kind of work for a while with the clutch depressed. You would not want to do this if you are on hills though...except maybe if you were holding the clutch pedal down with you foot. Even then, having the clutch break free on a hill, and the tractor start drifting suddenly downwards, might not be a good thing, to say the least.

For lack of a better idea, I'd probably try running the tractor a while, on level ground, with the clutch depressed to see what happened. Also, some have reported moving slowly towards a tree and impacting the tree at slow speed with the loader bucket as a way to shock a stuck clutch free...

 

[theboman]

Have you crawled under your tractor and looked for a stick, etc. lodged in the linkage?

 

[Junkman]

If this is a wet clutch, then there is no way to break it apart from the pressure plate. If it is a dry clutch, and there is an inspection plate, possibly you can get something in there to pry the two parts apart. When there is a hydro involved, then there is no way that the pushing on the tree method will work. The clutch is either engaged or not, and the tractor movement is controlled by the hydro, not the clutch. I believe that you are doomed to doing the repair the old fashioned way... take it apart and put in a new clutch facing.

 

[Henro]

<font color="blue"> When there is a hydro involved, then there is no way that the pushing on the tree method will work. The clutch is either engaged or not, and the tractor movement is controlled by the hydro, not the clutch. </font>

Let's carry this thought a little further...

On a hydrostatic transmission tractor, the clutch is still somewhere in the power circuit, between the rear wheels and the engine, isn't it?

I know on mine if I push in the clutch, while the engine is running and the HST is in gear, the tractor will drift just like a standard shift would.

So it would seem to me, if the clutch were rusted to the pressure plate, and the clutch pedal were depressed, and the tractor was against something while the HST pedal was pushed causing the tractor to want to move, then the net effect would be the same as it would be if the tractor were a gear transmission tractor.

I'm not trying to debate the possibility that the HST might not produce the amount of torque on the clutch disk that a gear drive might...but it sure seems to me that it would be possible to break a clutch plate free from the flywheel on a HST tractor, using the same methods that have been prooven to work on gear tractors.

What am I missing?

 

[KennyV]

Henro,
as usual /forums/images/graemlins/cool.gif… you have nailed it.

You are not missing anything.

If he dose as you described it should free up. Using high range will put more torque on the clutch, but hi or low will get it done. KennyV.

 

[Pks]

According to my B2400 HST parts book, the clutch feeds power from the engine to the HST pump. The HST pump then acts like a geared transmission in that the power is connected from the clutch to the rear wheels. Therefore the clutch can be partially engaged which would then feed a proportional amount of torque to the wheels.

FWIW, I think Henro's thoughts are right on the mark.

Are you sure the clutch-fork is engaged against the throwout bearing (not sure how to test that)?

The attachment shows the B2400 HST clutch housing and bearing.

 

[Kiohio]

I heard this from a friend of mine on how to fix it without splitting, at least give it a shot. Drive the tractor alot use it etc get it good and hot. Then when finished press the clutch pedal all the way down and lock it. Let it set/cool overnight. It should be free in the morning. If that doesn't work I would try one more time doing everything the same...get it warm etc. Then go to that tree...let it cool overnight and try to move the tree the next morning. It's worth a shot.
Have fun!!

KO

 

[chucko]

does the cluch not also work the PTO? if so with the pedel in an a good load (like a tiller) on the pto might work

 

[Pks]

Chucko, good point!

 

[Junkman]

I concede that you are correct. After doing some reading and asking a friend that is more familiar with tractor clutch/hydro set ups, he said that the tree method might work and to do it in high gear. He also said that it might just tear the clutch facing off the disk if it is rusted up solid.

 

[Mayhem]

So how does a clutch get "Stuck"?
Is this simply from age and lack of use to where it just rusted up?

 

[RobertN]

From sitting without use, and moisture buildup. While sitting, there can be moisture around and permeate the disc a little. Once that happens, if the the flywheel surface starts to rust, it will adhere everything together.

Things like cars and tractors do not "sit" very well. Moisture builds in the engine, things like clutches and brakes get corosion which binds them, seals dry out and start to leak...

 

[JimR]

You can also try just driving in forward with the cluth depressed and snap it into reverse. I would try it going slow. Another thing to try is to pull a large tree, stump, car, pickup, whatever around with the clutch depressed. As mentioned above, you may tear the face off the clutch plate. At this point in time you have nothing to lose.

 

[Tim_D]

Thanks to all you guys, I knew I could count on you for your valued opinions! Scarie about breaking off the facing of the clutch surface,,, did not think of that.
Yes, I have checked for a stick in the linkage rod, matter of fact I had to take the rod off the tractor to free it up to attempt an adjustment. I have a tiller on the tractor currently, I will try keeping the clutch peddle depressed during my next tilling job.
Thanks again for all your ideas guys!
Tim

 

[NIXON]

Tim .
No suggestions here ! But I certainly hope that your problem is solved without anything costly . Anyway , welcome to TBN .
Hopefully your posts in future will be less stressful to You. John

 

[Junkman]

As it has been pointed out, it is moisture. When a vehicle or tractor with a clutch is going to be stored for a while and moisture is going to be a concern, the best thing to do is use something to hole the clutch pedal down. This way, the clutch lining will not be in contact with the pressure plate and flywheel. The clutch disk is sandwiched between these two parts and when the clutch is released, it transmits the energy from one to the other. Rust is always a major problem with any machinery that isn't used regularly. When I take my old car out for a ride after it has been in storage, the brakes always grab, because of the rust on the inside of the drums. After a few stops, this rust is worn off and the brakes act normally again. The same can happen with clutch linings...

 

[Tim_D]

Hey thanks for your input 'Junkman' and 'Nixon'.
Nixon-it was stressful for me making this discovery after owning it for a month, felt really stupid that I didnt discover it before the purchase. The bright side of all this that the drive powers the tractor as it should, I just do not have the control (of the Clutch Pedal) that is possible. I will live with it for now as I do not plan to use the PTO that frequently.
JunkMan - you must have a vast experiance with these Kubota's and/or mechanics in general. I am the 3rd owner of this B20 so it is hard telling how long the clutch has been stuck. It is possible it has been seized for years. For now I will take the conservative approach here and not force a clutch distruction. I bought the tractor to use not another ($) project !
Thanks again, Tim

 

[Glenn1]

The manual for my B7500 has instructions for using the wood blocks supplied with the tractor to prevent this problems. The maunual says to install the blocks if the tractor is parked more than two weeks. I have been told it is due to the new material for clutchs due the health issues with asbestos.