Third B7100 clutch in 4 years!?!?

[#40Fan]

If the clutch only controls the PTO, I'd be looking there. Whether that would be from the clutch to the PTO shaft or any implement that you run. Make sure there isn't something that is binding, causing the clutch hub to be loaded against the springs.

While the tractor is split and if you can, engage the PTO and turn the transmission input shaft by hand. See if you can feel any binding. If possible, connect your implements and try turning the input with them attached.

 

[torch]

If the clutch only controls the PTO, I'd be looking there. Whether that would be from the clutch to the PTO shaft or any implement that you run. Make sure there isn't something that is binding, causing the clutch hub to be loaded against the springs.

The B7100HST clutch drives both the HST and the PTO.

I'm not sure I follow the logic here. Loading is a fact of life on a clutch, be it propelling the tractor or powering a PTO attachment. Binding is bad and robs power, but I don't think the clutch cares if the load is caused by friction in an implement, driving up a hill, or blowing snow. The clutch materials should be adequate to the horsepower of the motor. Even shock loads (like churning up rocks with a tiller) should be considered a fact of life for a tractor.

Or are you thinking something is setting up a rhythmic vibration at a natural frequency, as described in Dave's article?

I will say I have never noticed any signs of binding when rotating the PTO output shaft, as when connecting to an implement or replacing a shear bolt. But I'll try if from the propellor shaft and see if that makes any sort of difference. I can't hook up any implements right now though -- I pushed it into the shop backwards before splitting it.

 

[GreensvilleJay]

Ok, copied this from the onlineparts..... 6 would be the throwout bearing, 17 the 'properllor shaft' that thefront goes into the 'pilot bearing', black band is the splines for the clutch assy... so the rear of the prop shaft is supported by the 'CV' joint,that I assume is 'pinned (19) to the input shaft of the tranny.
If that CV joint is bad (missing balls ,rusted, binding...) THAT could allow the shaft 17 to NOT be centered and true possibly causing the clutch failure,flop around...ooopsy....
You said it was a PITA to get to....hmmmm.... how old is it, maybe it's never been serviced ???

I KNOW the CV ( double carden ?) joint on my forklift NEEDS to be replaced. ONLY access is from below and I'm not paper thing anymore ! Without a 'pit' ,just how do you safely raise a 7,000 object up 2 feet ?
sigh...maybe this summer.....

Kinda running out of straws but dang I feel bad for you, pretty sure you need to service the CV joint.

 

[Pau7220]

I’d also check the input shaft for runout, along with pilot bearing to input shaft fit.
Something is not right with those kind of multiple failures.

 

[torch]

I think I found the underlying problem. The engine is not bolted to the bell housing. A steel plate is bolted to the engine via the inner holes then the bell housing is bolted to the plate's outer holes:

The plate was warped, dished in the centre so the crankshaft was not pointed directly at the transmission. A couple of hours and a shop press and it's flat again now.

The pilot bearing was fine, still sporting it's yellow nylon coating. ID was actually slightly smaller than the ID of the brand new one, but it probably compresses when pressed into the flywheel. Bushing ID was 0.009" larger than the shaft OD.

There also seems to be what I would consider excessive radial play in the CV joint by feel. I'll have to investigate that further, and I imagine I will have to split the tractor again to change it but that can wait until after the snow season.

More later, but right now it's off to work. (24 hour shift Friday, reassemble tractor Saturday, 24 hour shift Sunday -- Coffee and Tylenol were involved.)

Thanks for all the suggestions. Happy New Year.

 

[Dave_eng]

I think I found the underlying problem. The engine is not bolted to the bell housing. A steel plate is bolted to the engine via the inner holes then the bell housing is bolted to the plate's outer holes:

View attachment 93273

The plate was warped, dished in the centre so the crankshaft was not pointed directly at the transmission. A couple of hours and a shop press and it's flat again now.

The pilot bearing was fine, still sporting it's yellow nylon coating. ID was actually slightly smaller than the ID of the brand new one, but it probably compresses when pressed into the flywheel. Bushing ID was 0.009" larger than the shaft OD.

There also seems to be what I would consider excessive radial play in the CV joint by feel. I'll have to investigate that further, and I imagine I will have to split the tractor again to change it but that can wait until after the snow season.

More later, but right now it's off to work. (24 hour shift Friday, reassemble tractor Saturday, 24 hour shift Sunday -- Coffee and Tylenol were involved.)

Thanks for all the suggestions. Happy New Year.

Torch
Really great that you are finding issues to account for your rapid break up of your clutch disk.
I still wonder if your loader attachments to the tractor have cause this plate to bend/warp.
Dave

 

[GreensvilleJay]

Wow, at least all your hard work paid off, you've FOUND the problem ! I'm curious what happend 3 clutches ago, though I suspect a 'loader operation' may have caused it. Something 'bent' the tractor in half.
The CV joint is probably OK but like you said, make it a lazy SUMMER project.....you deserve a rest !

 

[torch]

Torch
Really great that you are finding issues to account for your rapid break up of your clutch disk.
I still wonder if your loader attachments to the tractor have cause this plate to bend/warp.
Dave

I think that is entirely possible. I was looking at the framing from post to front bumper and re-evaluating. I think I'll be adding some additional bracing.

 

[woodman55]

I think I found the underlying problem. The engine is not bolted to the bell housing. A steel plate is bolted to the engine via the inner holes then the bell housing is bolted to the plate's outer holes:

View attachment 93273

The plate was warped, dished in the centre so the crankshaft was not pointed directly at the transmission. A couple of hours and a shop press and it's flat again now.

The pilot bearing was fine, still sporting it's yellow nylon coating. ID was actually slightly smaller than the ID of the brand new one, but it probably compresses when pressed into the flywheel. Bushing ID was 0.009" larger than the shaft OD.

There also seems to be what I would consider excessive radial play in the CV joint by feel. I'll have to investigate that further, and I imagine I will have to split the tractor again to change it but that can wait until after the snow season.

More later, but right now it's off to work. (24 hour shift Friday, reassemble tractor Saturday, 24 hour shift Sunday -- Coffee and Tylenol were involved.)

Thanks for all the suggestions. Happy New Year.

Well that's great that you found the underlying cause. Good work.

 

[GreensvilleJay]

FWIW....

If the frame begins at the 'bell housing' area, maybe consider adding supports all the way to the rear axle ?
This effectively builds a 'truss' ,top section being the engine.bellhousing, tranny, read end, the lower section , the original loader frame AND the extension to the rear end. This should prevent the tractor from bending at that 'plate' (aka busted teeter-totter) I haven't seen any pictures of how the loader frame is attached but I did a similar 'extension' mod to my first CJ-5 when we repaired the snowplow harness bolted to the 1st foot of frame.
ATVs with plows do a similar 'full length' frame system.

 

[torch]

FWIW....

If the frame begins at the 'bell housing' area, maybe consider adding supports all the way to the rear axle ?
This effectively builds a 'truss' ,top section being the engine.bellhousing, tranny, read end, the lower section , the original loader frame AND the extension to the rear end. This should prevent the tractor from bending at that 'plate' (aka busted teeter-totter) I haven't seen any pictures of how the loader frame is attached but I did a similar 'extension' mod to my first CJ-5 when we repaired the snowplow harness bolted to the 1st foot of frame.
ATVs with plows do a similar 'full length' frame system.

My subframe does run to the rear axle, but the posts are just rearward of that plate, so the area of concern is from the posts forward. My original design mirrored Kubota's in considering the engine as part of the "truss" as you call it. My thoughts are to take the engine out of the equation. I'm at work right now, but I'll do a sketch some time in the near future to explain my thoughts better.

 

[Lil Foot]

Congratulations on your detective work, sounds like you have the problem solved.
Any idea how much the plate was warped?

 

[GreensvilleJay]

FWIW, the Freeman loader frame on my A-C D-14 is made from 3" OD tubing, front mounted on side of engine side plates, read is on the rear axle. It's really a 'beefy' frame.Perhaps your subframe and be 'beefed up' ??

 

[torch]

Congratulations on your detective work, sounds like you have the problem solved.
Any idea how much the plate was warped?

A lot:

 

[torch]

As I said, I'm at work so I don't have access to my own computer and files. So I'm stealing some images from the internet here. First, this one by Wolfman in 2014, showing the loader subframe mount location for new style B7100HST. Just rearward of the plate:

Here in an image by Lil Foot in 2013, you can see where the gear drive version of the B7100 mounted the subframe, forward of that plate, below the muffler:

In retrospect, I think that while the newer design makes splitting the tractor much easier and allows for use of the forward-facing mid-PTO, the earlier design put far less strain on the plate. I think I want to add some bracing -- perhaps bolted to allow easy access when necessary -- to bridge that engine-to-bell housing joint.

 

[GreensvilleJay]

question.
Is your sub frame from front to back just flat plates or tubing(say 1 by 4 ) ??
There's a big difference in 'flexing'. tubing is like a 'boxed' frame,or truss, dang near impossible to bend.
hard to tell in the photo, but it looks like simple 'bar stock',maybe 1/2" thick, 4" tall ??
Also,where the lower horizontal bar meets the triangular flat plate, the overlap isn't very wide, again could just be the picture.

 

[Lil Foot]

A lot:

Damn!
That IS bent!
Nice catch!

 

[torch]

question.
Is your sub frame from front to back just flat plates or tubing(say 1 by 4 ) ??
There's a big difference in 'flexing'. tubing is like a 'boxed' frame,or truss, dang near impossible to bend.
hard to tell in the photo, but it looks like simple 'bar stock',maybe 1/2" thick, 4" tall ??
Also,where the lower horizontal bar meets the triangular flat plate, the overlap isn't very wide, again could just be the picture.

The photo above was Lil Foot's of the OEM subframe. Mine is doubled 1" heavy wall square tubes stitched together. Here's an image of the front brace, same technique used for the subframe from post mount to axle:

 

[GreensvilleJay]

T, my 'gut' says it's not stiff enough, 1x4 , 3/16 wall or 2x4, 1/8th wall would be a lot stiffer ( less deflection).
maybe one of the guys with a 'Machinery's Handbook can do the 'math'. It should also be one piece from front to back.
You could turn it into a truss by adding a few 2" long .'spacers' of 1" tubing and then a full length, one piece bottom 'chord' of 1" tubing.

 

[torch]

This should hold it:

Now it's bolted to both the FEL mount and the engine. Both sides.