Third B7100 clutch in 4 years!?!?

[GreensvilleJay]

just ONE spare ????? sorry but man I feel for you...

I can't believe this is a well known 'manufacturing defect' otherwise there would be a recall or a LOT of 'upset' owners of that model tractor.
I'm guessing it's some kind of 'mechanical alignment' issue ??

 

[fried1765]

Given the rate I'm going through them, can you blame me? <lol>

No....I cannot blame you, and with your being in Ontario, I understand that parts issues can be a problem.
I had a seasonal residence in NS for 13 years, so can certainly appreciate availability issues.
Defensive parts buying is sometimes necessary!

I had a new side by side refrigerator electronics board fail.
Out of warranty by 4 weeks!
Canadian replacement board was to cost $300+.
It was at end of my season, but I had a weak old basement fridge, suitable to struggle through with.
Bought a new board in USA on E-Bay for $100, to take with me for next season.
Was concerned that new board might not be a lasting fix.

Bought a new small (9 cuft.) chest freezer, in the USA, and a portable external temperature controller for it.
Took the new small freezer, and controller to NS.
(You can use a freezer as a refrigerator, with an external temp. controller).

Upon arrival for next season installed new side by side refrigerator board.
Everything worked perfectly!

Sold property 12 months later, and took the new little freezer back to the USA.
Still have it!
Have never used it!

 

[GeoHorn]

Buying a spare to keep on-hand is a brilliant solution! That way you’ll NEVER NEED THE SPARE!

 

[torch]

Buying a spare to keep on-hand is a brilliant solution! That way you’ll NEVER NEED THE SPARE!

Precisely. Murphy's Law says something else will break, but not the part I have spares for!

 

[North Idaho Wolfman]

Check flywheel for run out / warpage.
Only turn the flywheel if its warped.
If that's good, I use an orbital sander and 50 - 100 grit sandpaper and put a good swirl finish on them.

I don't want to sound like a jerk, but is it using the shouldered bolts on the flywheel?
And because of the shouldered bolts do you notice that you can only put the flywheel on one alinement of the bolt pattern?

 

[torch]

Check flywheel for run out / warpage.
Only turn the flywheel if its warped.
If that's good, I use an orbital sander and 50 - 100 grit sandpaper and put a good swirl finish on them.

I don't want to sound like a jerk, but is it using the shouldered bolts on the flywheel?
And because of the shouldered bolts do you notice that you can only put the flywheel on one alinement of the bolt pattern?

You don't sound like a jerk, and yes, as I recall the flywheel could only go on one way. I believe the bolt hole spacing was slightly off if the flywheel was not correct.

I have not yet split the tractor, but here's a photo from the last time:

 

[torch]

I have 3 L's and 4 B's that have been running setup's from him ( Jeff Cube ) and no failures.

I don't yet know what the quality of the product is, but I can't fault the service. I ordered it just after 8am. 20 minutes later I had an e-mail saying a shipping label had been created. By 12:55, USPS tracking indicated the parcel was in their possession. That boy isn't sitting on his hands, that's for sure! Who knows, maybe it'll be here before the OEM parts.

 

[Vigo]

That flywheel looks great.

Keep in mind the damper springs themselves are not the area that would be flexed by a flywheel runout issue. That’s extremely unlikely anyway, and if you did have notable axial runout you would probably experience it as a noise symptom while cranking because it would cause weirdness with the starter drive.

 

[torch]

Shipping update: eBay order stuck in the USPS facility in Chicago. Kubota dealer called this morning to say my parts are in. Kubota wins that round!

 

[torch]

I got the tractor split today. Same old, same old:

On the crankshaft, flywheel TIR seemed to be 0.003". It was a bit hard to measure since the crankshaft endplay was 0.008". That is within the specified tolerance of 0.006" to 0.012" and well within the limit of 0.20". But I can't find a spec for flywheel TIR in the manual.

I think Vigo is right though -- the splines will easily accommodate 3 thou. And I think if it was excessive, there'd be some witness marks on the splines, but I don't see any.

I'll take the flywheel off and check it for flatness on the surface plate, then make sure the mating faces at the crankshaft are scrupulously clean. But I don't really think that's the problem.

 

[TheOldHokie]

I got the tractor split today. Same old, same old:

On the crankshaft, flywheel TIR seemed to be 0.003". It was a bit hard to measure since the crankshaft endplay was 0.008". That is within the specified tolerance of 0.006" to 0.012" and well within the limit of 0.20". But I can't find a spec for flywheel TIR in the manual.

I think Vigo is right though -- the splines will easily accommodate 3 thou. And I think if it was excessive, there'd be some witness marks on the splines, but I don't see any.

I'll take the flywheel off and check it for flatness on the surface plate, then make sure the mating faces at the crankshaft are scrupulously clean. But I don't really think that's the problem.

I am pretty sure there IS a problem and its not parts quality....

Dan

 

[torch]

I am pretty sure there IS a problem and its not parts quality....

Dan

I agree. I'm just not sure what it is.

 

[Dave_eng]

I agree. I'm just not sure what it is.

Torch
I am trying to "think outside the box" when it comes to your recurring problem. Because it seems it is the torsional springs which are failing I wanted to get you thinking in a different direction other than alignment.
I have in my archives this technical paper:
The Role of Mechanical Clutches
in Dampening Torsional Vibrations

Could any of your modifications be causing significant changes in the engine. Not shaking which would be noticeable but twisting forces.......... a front driven hydraulic pump perhaps.

All of the above are just stabs in the dark.

Dave

 

[ken erickson]

Torch,
If I read your first and follow up posts correctly you installed a new pilot bushing after the first fail with a new OEM bushing. Did you check for proper clearance between input shaft and ID of bushing along with ID runout AFTER it was installed in crankshaft? Like others, just taking a stab in the dark.
Good luck with the new install!

 

[torch]

I will have a look at those tomorrow -- off to bed now. But I'm not so sure that the torsional springs are the point of failure, they are falling out and I think being damaged in the process. In this latest instance, one spring was badly distorted but the other two were just kicking around loose in the bell housing. I think the damaged one got jammed, causing the engine to stall and that is how it got damaged.

I think they are falling out because the plate that is supposed to hold them is fatiguing and failing. But why it is fatiguing is not clear to me.

 

[torch]

Torch,
If I read your first and follow up posts correctly you installed a new pilot bushing after the first fail with a new OEM bushing. Did you check for proper clearance between input shaft and ID of bushing along with ID runout AFTER it was installed in crankshaft? Like others, just taking a stab in the dark.
Good luck with the new install!

I don't think I can directly measure the clearance. But I can measure the installed bushing ID and subtract the shaft OD.

 

[ken erickson]

I don't think I can directly measure the clearance. But I can measure the installed bushing ID and subtract the shaft OD.

I think that will work just fine but checking run out of installed pilot bushing is important also.

 

[GreensvilleJay]

OK, looking at the damage and how it's made..........
I don't know if this is possible but...
if the center spline piece gets 'hung up' or 'stuck' or off center to the rest of the 'plate', could that twist or bend the 'plate' close to the 'hub' ? Some kind of mislignment that after several clutch operations , it bending there fatigues the steel and it fails ? The metal holding the 4 springs seems like 'thin tin', so enough bending and it could fail.
For a fairly new unit, that hub looks 'dirty' to me.
Is there any binding on the splines of the tranny input shaft ? maybe a nick or burr ? Is there too MUCH gap between the splines of the clutch and the input shaft ? Have you replaced the front bearing of the tranny ? If it was 'loose', it could allow the shaft to move ,possibly bind up the clutch ?
If the tranny wasn't dead true to the bell housing, could that be the cause ?
Is the clutch engagement smooth ? No 'sticking' with 'popping the clutch' type stress ?
There has to be some kind of misalignment, without being there it's very hard to see though.

Have you shown pictures to a tranny shop , to see what they say ??

 

[torch]

Is there any binding on the splines of the tranny input shaft ? maybe a nick or burr ? Is there too MUCH gap between the splines of the clutch and the input shaft ? Have you replaced the front bearing of the tranny ? If it was 'loose', it could allow the shaft to move ,possibly bind up the clutch ?
If the tranny wasn't dead true to the bell housing, could that be the cause ?
Is the clutch engagement smooth ? No 'sticking' with 'popping the clutch' type stress ?
There has to be some kind of misalignment, without being there it's very hard to see though.

I should note that the transmission input shaft does not connect directly with the clutch. There's a "propellor" shaft between the two. One end of the propellor shaft has the male splines that engage the clutch (and the bearing surface that engages the pilot bushing). The other end connects to the transmission input shaft via a splined CV joint.

Access is very difficult, but I'll see if I can find any issues with the CV joint. From the clutch end, it seems moving freely without excessive play.

 

[Russell King]

If the pilot bearing was off center in the crankshaft would that be causing the failure?

I recall posts that describe the crank shaft being damaged when the pilot bearing was destroyed. If the repair was done off center then the shaft would be moving in a strange path trying to force the center of the clutch plate out but the pressure plate is clamping it somewhere.. That would cause the fatigue of the steel while driving the tractor around through the compression and stretching in every revolution