B7100 premature clutch failure

[MMudd]

New to this forum. Just purchased this tractor. 1100hrs. Previous owner just replaced clutch.
I have used it very little -50 hrs?. Since it is Hydro, only use of the clutch is really to engage the PTO for mower deck, whish is all i've used tractor for.

Just before the breakdown, you could hear a roar/growl when clutch pedal was depressed, like the clutch disc was vibrating when pressure plate was released andnoise subsided at lower RPM. few weeks ago, I had to fish a spring out the bellhousing rattling around in there. I figured something was going wrong, but clutch still functioned. A few days ago the tractor stopped suddenly.
Another clutch plate spring came off the disc and lodged between flywheel and the bellhousing. locked everything up.

I split the tractor, and 3 of the 4 springs on clutch disc were out which caused flyweel to bind up against bellhousing! observations:
-asbestos disc Facing looked new
-Flywheel had been resurfaced, could still see the machine marks on all of it.
Throw Out bearing looked new

Pilot busing was shot and did not appear to have been replaced, or if replaced wore down very quickly.
I'm thinking this was the problem all along?
Questions:

Is it safe to assume a bad pilot bushing caused prematur disc failure- Springs popping out of disc?

Is it possible, in, binding up, the flywheel has been deformed in this type of breakdown? I planned to resurface flywheel again, and assume machine shop can tell if it is bent or warped when they go to resurface?

I'm going to replace all of the clutch components while I'm here .

Thanks for any suggestions. Mark

 

[kubotasam]

I don't think you could have bent the flywheel. When you remove the flywheel be careful to make some marks so you can get it put back on correctly. There is no indexing pin and the bolt holes in the flywheel look like the can line up with any position on the crankshaft. There is only one correct orientation for the bolts. If you did not mark it sight through the holes carefully and make sure you can turn all of the bolts in by hand before you tighten them. A bad pilot bushing will allow the clutch disc to flex which could account for your failure.
(not exactly sure about this next bit of info) I think some B7100's have a pilot bushing and some have a pilot bearing. So check into what part you need before replacing. Do you know the trick of packing the hole with grease and hammering in a bolt or metal rod to force the bushing out of the end of the crankshaft?

 

[Dave_eng]

Although this is not the quick answer you would like, I think it would be useful to understand why the springs are present in the clutch disk. Torsional vibration generated by the firing pulses of the engine travel through the drive line and shock the gears. The springs help absorb this twisting vibration and prolong the drive line life. They are not there to soften the engagement of the clutch as you release the pedal.

Something seems wrong to allow the springs to come out. Perhaps the wrong disk and something is pressing on part of the hub to spread the inner layers apart. I would not just replace the springs and put it back together.

Was the pressure plate changed as well, some for the release bearing(s)? Was the disk in backwards?

Dave M7040

 

[MMudd]

Thanks for the replies and tip on getting the bushing out with grease. That was going to be my next challenge assuming it is still in there?

Everything in there appeared to have been recently replaced excet pilot bushing. It was toast, just a thin sliver of metal that was not even a complete circle came out so far. Not sure if there is more left in crankshaft end? It does not appear to be a roller needle bearing. Figured when I get new pilot, I'll have better idea of size and if there is more to get out of crank. Also I will make sure to check fit of pilot on tip of imput shaft,

I had a look at the components with an experienced mechanic.

Imput shaft tip and splines looks good, it was supposedly replaced? I'm going to take it all the way out and make shure it is not bent and I will be sure to check fit of new disc.

Flywheel shows no sign of clutch slippage- circular lines, heat spots etc. can still see all machine marks from resurfacing. This clutch did not get used much since resurfacing.

The metal spring holder center of clutch disc is cracked radially, which allowed springs to come out. The splines on the disc look very worn and fit sloppy on the imput shaft. Very little wear on aesbestos lining though.

I have a feeling they had the wrond disc (or a bad rebuilt?) on there and did not install new pilot bushing and this caused the failure?

I'm replacing all of the components (disc, pilot, release bearing, pressure plate) including the backing plate that is bolted to the engine, which got bent upon bind up. Any other things I should check for?

This otherwise seems like a solid tractor (1100 hrs), and no more than the clutch will get used (its a Hydro), I can't imagine wearing it out only using to engage PTO, unless these things are known for weak clutch?

 

[North Idaho Wolfman]

Do you know the trick of packing the hole with grease and hammering in a bolt or metal rod to force the bushing out of the end of the crankshaft?

That is one great piece of info!!!!

I would bet that they put the disk in backwards and that's why it failed, I've seen that done, the throwout bearing hit's the springs every time you depress the pedal!

 

[BUCKET]

I have just had the same problem on my B7 100.
I split the tractor and the disk was shattered and one of the springs was jammed in behind the flywheel.
I did notice the disk was actually stuck on the spline and not moving .
It took a fair wack with the hammer to get it off the spline.
Should a small amount of grease be put on the spline to help movement ?
Or would this find it's way to the flywheel and cause slippage ?

 

[BadDog]

The disk was shattered to the point that the hub stayed on the input shaft and passed through the pressure plate? I've seen them shed the friction material, but never saw one do that. But that would mean the lever fingers on the pressure plate were gone too. I must be missing something...

In any case, everything in there should be clean and dry. Grease would not only risk migrating to the clutch (which actually makes it grabby rather than slipping) but it would also combine with normal grit to form an abrasive paste initially, and eventually cake into a relatively solid substance that would hinder rather than improve movement. Not that the clutch should be moving much on that shaft anyway.

 

[BUCKET]

No , the disk was still behind the pressure plate and connected to the disk hub , well what was left off it anyway
When I took the pressure plate off to get the disk off it was stuck on the spline .