YM 3000 Flywheel

[chriswheeler]

Hi all,
Installing a new clutch in my YM3000 and wondering if there is a min/max spec out there for resurfacing the flywheel. Step in the flywheel has already been resurfaced as some point in it's life. Measurement I'm looking for would be the min/max from the face of the flywheel to the surface the clutch disc contacts on the flywheel. If this step is to deep, won't matter what new parts I bolt up. Looked in the service manual, ( I have one ) no spec. Also have a JD950, and the service manual for that, no spec. This step on mine now measures .185 deep measured with a depth mic. Would appreciate any info if you have it, thank you,
Chris

 

[Car Doc]

I cant see the flywheel but if it worked before why couldn't you just take a 2" 3m roloc disc on a die grinder and surface it with that? A rivet groove will not hurt anything if its got one fwtw.

I do cars and trucks all the time that way that have hydraulic clutches where you cant surface them if you wanted to and it works just fine on cars that run thousands of miles a month not just a few hours a year. hth :thumbsup:

 

[chriswheeler]

The reason I split the tractor is I had run out of clutch adjustment and the drive was starting to slip. After the split I discovered that the clutch disc and pressure plate were in fair to good shape. Clutch disc wasn't into the rivits and measured almost .300 thick. Looking at the setup hard, throw out, springs, fork and pilot bearing are in good shape. Looking at the flywheel closer, it appears at some time in it's life someone has resurfaced the area the clutch contacts. This area is cut below the flat face of the flywheel by .185 or so. Thinking there should be a spec where the surface would be cut to deep and remove proper pressure from the clutch disc, or with new parts provide much less adjustment for wear. If it was just a matter of resurfacing the flywheel, no problem, I'm a machinist with a lathe at home to do the job just fine. But I realize that at some point this surface can be cut below a usable spec. And that is where the question comes from. Min/Max spec on resurfacing the flywheel. This tractor is a VN recon, so anything is possible. ( you would not beleave what I've found and fixed so far. Still all things considered not a bad deal if you don't mind turning a wrench )
Chris

 

[California]

...is a VN recon, so anything is possible. ( you would not believe what I've found and fixed so far. ...

Considering the source - I wonder if your .300" disc is correct for that model. Maybe you could calculate the thickness of disc you need to restore a normal range of adjustment then find a suitable thicker disc off something else? Or maybe have your disc relined with much thicker facing.

I expect your pressure plate was reconditioned by grinding it down too.


Someday I'd like to read a description of the oddities you have encountered.

 

[Car Doc]

Id ponder turning down the surface the pressure plate mounts on then since you are the guy doing the machining. In theory that will put more tension on the disc and force the PP fingers outwards hopefully giving you more adjustment. A shim between the crank and flywheel may be necessary as well? hth

 

[chriswheeler]

And that is exactly what I'm trying to get done here. If I can find the min/max spec, I can face the outer surface of the flywheel that the pressure plate bolts to and bring it back into spec for the clutch face if need be. Just need to find out what that spec is. Our friend Vanna in Sac didn't have anything to do with this one, most likely came out of the shipping container this way. Think I've got 7 years out of this so far, I've got no complaints. Here is another heads up for all with a loader. Pulled the flywheel to install a new pilot bearing. Found that 5 of the 9 bolts that hold the bell housing to the engine broken off with the heads rubbing the back side of the flywheel. Heads were trapped by the casting with more than 50% of them ground away by the friction of the flywheel. On and off for years I've had a " noise " couldn't locate. Guess what, I found it. Lucky I didn't break this tractor in half !! Drilled and used easy outs to remove the bolt stubs, ran a 10 X 1.25 tap into the block to clean up the threads. Threads in the block are OK. Bolts used on the bellhousing were of a low grade, combine that with the load exerted by the front loader, they didn't last. ( Koyker 160) Thinking anyone replacing a clutch needs to remove the flywheel and check the bell housing bolts. I'll machine a new pilot bearing today and be ready. Sure wish I could get my hands on that spec. Might have to contact Hoye Tractor and see if they can measure a new one for me.
Chris

 

[Car Doc]

I will give you what I have in my 336 manual use at your discretion.


clutch disc measurements

disc od-8.46"
facing thickness both sides-.327-.350" wear limit .300"
rivet head depth-.05- wear limit .112" (this makes no sense but thats what it says fwtw I think thats backasswards)

As far as the flywheel all it says if its not within .008" straight replace it so I take that as there is no surfacing allowed. hth

(now in that lies the challenge as far as I am and I presume you are too concerned Id go for it is my advice!)

 

[chriswheeler]

Car Doc,
The pilot bushing is pressed into the flywheel itself, no setback with the flywheel necessary unless the surface the clutch disc rides on is grossly out of spec. Then the throw out bearing travel becomes a issue. ( good idea though I could sure make that spacer easy enough) Plenty of spline for the clutch plate drive as well. I have enough room to machine 1/8" off the face the pressure plate mounting surface if need be. But don't want to assemble this and find that there is so much pressure that I can't disengage the clutch ?? And there is the issue of the throwout bearing moving in and still getting enough to disengage. Best fix so far, ( if I need one ) would be to find out the min/max on the step in the flywheel. Guess the easy answer might be to just try to buy a new flywheel. Machinist in me would go for a fix first.
Chris

 

[Car Doc]

Hey Chris the shim is more for adjustment in the lever that is mounted in the bell housing where you are moving the PP farther away from the fork shaft CL. :thumbsup:

On the Jap cars I work on even as much as .050" will drastically affect how the clutch acts.

 

[chriswheeler]

Thanks Car Doc,
No surfaceing allowed, I can clearly see lathe tool marks on this one, makes for a new flywheel purchase I guess. Give Hoye a call, see if one is available, thanks for your time and effort,
Chris