1983 B7100 Clutch won't disengage after sitting for 5 years

[blake_s]

I'm working with a newly inherited 1983 Kubota B7100D 4WD Gear Drive tractor that has been sitting since 2021. The tractor starts easily, drives, shifts, and otherwise seems to run well, but the clutch will not disengage. The last person who used it regularly remembers the clutch working normally before it was parked.

• The clutch external linkage matches the B7100's specs of 2-4mm free play with 8mm of travel. I can feel the free play and then smooth, steady resistance through the rest of the travel.
• Looking through the inspection opening underneath, I can see the clutch release assembly moving back and forth when the clutch is moved.
• When I changed the transmission oil, it was free of debris and otherwise normal.

Does this sound like a stuck clutch disc or is there something else I should consider? If this does follow a stuck disc pattern, are there any freeing methods I could attempt?

Thanks!

 

[Caden]

I would try first driving the tractor with my foot on the clutch and standing on the brakes. I would assume if its just 5 yrs rusted it would break free before the engine stalls...

 

[North Idaho Wolfman]

Do you have a PTO powered ground engaging implement like a rototiller.
Running that and holding the clutch down can in some cases do it.

 

[blake_s]

Thanks for the responses, @Caden and @North Idaho Wolfman.

Wolfman, I don't have a PTO on hand. Caden, I read about that strategy and tried it today. My approach:

• I set the tractor in 2WD
• Placed transmission in high and F4
• Depressed the clutch
• Started the tractor up on a low throttle and let it start moving and then applied the brakes progressively over roughly 50'

I eventually tried it in F5 and in all five tries the tractor did stall, but no change in the clutch performance. I'm totally up for feedback on how I approached this or a different method.

Thanks.

 

[North Idaho Wolfman]

Try doing it in low gears and 4wd on.

 

[Caden]

Also, instead of slowly applying brakes, try stomping them quickly to a get a better shock.
Maybe increase the RPMs if you say you are at "low" throttle?

 

[airbiscuit]

I had a friend who had a Ford 8n with the same problem. He started it in high gear (fast), went high throttle and stomped on the brakes. it freed up after a few tries. Having it in 4wd is a good idea.

 

[blake_s]

Try doing it in low gears and 4wd on.

Thanks again for the thoughts on this.

I attempted the freeing methods again with the recommended variations (different gears, different RPMs, 4WD vs 2WD) and still no go. I ended up calling the local Kubota shop and explained my steps and results. Their recommendation is to do the split. If anyone here has additional thoughts, I'd appreciate them.

I'm going to attempt to do this split myself. I've watched a handful of YouTube videos. If any of you have videos that you feel great step-by-step guides or highly relevant, I'd greatly appreciate it.

 

[Caden]

A split seems extreme right now, but a dealer knows better than me.

I have two questions:
First, how did you apply the brakes during your earlier procedure?
Second, can you not see/ access clutch from an inspection cover underneath?

 

[torch]

From your description and investigations, I don't think this is the problem, but...

When I got my B7100, the previous owner told me the clutch didn't release properly. Now, mine is the HST version so it didn't take off down the road when started, but the PTO had to be engaged prior to starting.

I found the clutch rod was bent and the lever had been welded to the end of the shaft. The clutch didn't quite want to release fully even after straightening the rod and adjusting it to the maximum throw possible. Looking up through the access hole beneath, things were moving but they just weren't moving quite enough.

When I removed it, I found the lever was not square to the shifter fork, so it was not rotating the shaft far enough when the pedal was depressed. I had to reposition it a few degrees and re-weld it.

Not the best picture, but may help visualize what I am trying to describe:

Even if it is not your specific problem, I wonder if it would be worthwhile for you to temporarily adjust that linkage to the limit, to ensure maximum travel and pressure are applied when trying to break the clutch loose? When and if you get the clutch freed, readjust to specifications.

 

[Chanceywd]

From your description and investigations, I don't think this is the problem, but...

When I got my B7100, the previous owner told me the clutch didn't release properly. Now, mine is the HST version so it didn't take off down the road when started, but the PTO had to be engaged prior to starting.

I found the clutch rod was bent and the lever had been welded to the end of the shaft. The clutch didn't quite want to release fully even after straightening the rod and adjusting it to the maximum throw possible. Looking up through the access hole beneath, things were moving but they just weren't moving quite enough.

When I removed it, I found the lever was not square to the shifter fork, so it was not rotating the shaft far enough when the pedal was depressed. I had to reposition it a few degrees and re-weld it.

Not the best picture, but may help visualize what I am trying to describe:

Even if it is not your specific problem, I wonder if it would be worthwhile for you to temporarily adjust that linkage to the limit, to ensure maximum travel and pressure are applied when trying to break the clutch loose? When and if you get the clutch freed, readjust to specifications.

Good point about looking for linkage problems!

Just a few months ago I was getting ready to buy a clutch and split my non-kubota 8N.
It was dragging and grinding gears.
I figured the pressure plate must be bad and after adjusting all I could I noticed it was at the adjuster linkage.
It was cracked and rotating on the shaft going into the transmission. I removed and welded and full function returned.
I ordered a new aftermarket piece but haven't needed it yet.

Again not trying to go off topic just agreeing that looking over the linkage is a good idea.

Bill

 

[SDT]

A split seems extreme right now, but a dealer knows better than me.

I have two questions:
First, how did you apply the brakes during your earlier procedure?
Second, can you not see/ access clutch from an inspection cover underneath?

Agreed. No need to split at this time.

Dealer just wants to sell OP a clutch job.

 

[SDT]

I'm working with a newly inherited 1983 Kubota B7100D 4WD Gear Drive tractor that has been sitting since 2021. The tractor starts easily, drives, shifts, and otherwise seems to run well, but the clutch will not disengage. The last person who used it regularly remembers the clutch working normally before it was parked.

• The clutch external linkage matches the B7100's specs of 2-4mm free play with 8mm of travel. I can feel the free play and then smooth, steady resistance through the rest of the travel.
• Looking through the inspection opening underneath, I can see the clutch release assembly moving back and forth when the clutch is moved.
• When I changed the transmission oil, it was free of debris and otherwise normal.

Does this sound like a stuck clutch disc or is there something else I should consider? If this does follow a stuck disc pattern, are there any freeing methods I could attempt?

Thanks!

You need to figure out some way to load the tractor while the clutch is blocked down. Ideally, you will simply work it for awhile. Eventually it will free up. Borrow a rough cut mower and go out to mow in a wide open area. Shock loading is ideal.

FWIW clutches should always be blocked down during periods of olther than seasonal storage.

 

[Caden]

FWIW clutches should always be blocked down during periods of olther than seasonal storage.

I've heard that old Kubotas came with wooden clutch blocks. Found this image online. Kinda neat.

 

[D2Cat]

You need to figure out some way to load the tractor while the clutch is blocked down. Ideally, you will simply work it for awhile. Eventually it will free up. Borrow a rough cut mower and go out to mow in a wide open area. Shock loading is ideal.

FWIW clutches should always be blocked down during periods of olther than seasonal storage.

Agree with what STD said. May older machines have a lever by the left toe that flips down to keep the disc separated from the flywheel during long unused times.

 

[airbiscuit]

How many times did you try the go fast in 4wd and mash the brake (with the clutch down)?

 

[North Idaho Wolfman]

The B7100's have such a small clutch that breaking it loose, if it's rusted, is really hard to do.
The split is quick and simple and you probably don't need any parts.
DO NOT resurface the pressure plate or the flywheel.
Just a simple sanding with 120 grit sandpaper and you're good to go.
Reseal the clutch housing with RTV when you reassemble it to help keep water out.

 

[Paul Allwood]

If you do decide to split the tractor, here's a video by Marty T where he supplies a B7100. He's a New Zealander who seems to be really good at getting old machinery running. I've watched and enjoyed most of his YouTube videos.

 

[torch]

I didn't watch the whole video, but the title screen shows it split at the wrong spot to access the clutch. It needs to be split between the engine and transmission for this purpose.