Flywheel Resurfacing

[daves1979]

I am replacing a B7200D clutch disc, pressure plate and throwout bearing. The flywheel is good and has only glazing. Is resurfacing necessary and if so, what is the max amount that can be removed. I heard .060 is the maximum amount. Is that correct?

Thanks.

 

[D2Cat]

Dave, I've worked on a few Kubota engines, and I have never had a flywheel surfaced. And never had any trouble later.

But I would also suggest to replace the pilot bearing/bushing if there is one! You're there and virtually no cost.

Here's an easy way to get it out. Get a dowel that just fits into the bearing. Can be made out of any wooden round dowel you have. Fill the bearing with axle grease. Tap the dowel in gently with a hammer. Remove a couple of time to add more grease. Soon the bearing will be on your dowel.

 

[adventure bob]

When you "resurface" there's a couple of ways this can be done by nearly any auto machine shop.
The first is a simple scuff where the flywheel is chucked up and a circular stone is pushed against the face while rotating to give it that factory fresh flat surface. This removes an unmeasurable (at the auto shop level anyway) amount of material.
They can surface the flywheel which uses a cutter to remove material and thins the flywheel by whatever amount of material need to remove defects up to the max dimension of the manufacturer.
They can resurface and lighten, not that I would think you want a tractor flywheel lightened, but it can be done. They remove material form the backside of the flywheel to remove mass intentionally and then they rebalance it.
In the second two cases the flywheel should be rebalanced. I don't know if the motor is internal or externally balanced, but they need to know so they can keep the weight distribution correct for your engine.
If you wanted to get real OCD about it, you could pull the crank and pistons and have them balance the entire rotating assembly. Again, possible, but not sure of the value in tractor. Its not like they spin to super high RPMs.

 

[North Idaho Wolfman]

DO NOT resurface it!
I've yet to run into one that needed turned.
The tolerances on these flywheels are so tight it's not worth the risk.

Just take a simple sander like a DA, jitterbug or orbital, or even just a sanding sponge and give it a good scuff, that's all it needs.

 

[lugbolt]

Exactly what NIH said.

Kubota issued a publication a few years ago that had some flywheel resurfacing specifications. Basically, if you remove more than a thousandth or two (of an inch), it's no longer usable. I assume there is some leeway-though the publication did not specify. I've never had to resurface one. And I just did a clutch on an MX5100 that was the worst I've ever seen...but the flywheel was fine once I chiseled the friction disc off of it. Parts of it were welded to the pressure plate...if that tells you anything. The entire shop STUNK for a week while it was waiting for parts....

 

[D2Cat]

Lugbolt, here's a clutch that was in an L2050. The freeze plug on the back side of the block was partially removed and allowed the moisture to get in there!

I cleaned that flywheel up real good and it worked fine. It is some hard steel.

 

[daves1979]

Thank you everyone for the feedback/advise. I will "scuff" the flywheel as suggested. The flywheel is in very good condition as a straightedge (as accurate as that is) shows it to be even. I will try the grease idea to remove the current pilot bearing, although it looks great. It still has the yellow wax membrane on the inside. I looks as good as the new one i purchased. Is it absolutely necessary to replace? What is the proper tool to use to install the new one. I have seen many pilot bearing driver tools. The specs for the B7200 pilot bearing are:

ID: .550
OD: .630
length: .570

Thanks again.

 

[JeffL]

Yes, replace the bearing every time you separate the tractor. The cost is to low verses the time spent to separate. I have had pilot brgs fail on trucks with lots of life left in the clutch. I replace all four parts every time I pull a transmission. Just too much work not to! Jeff

 

[propuckstopper]

Dave, I've worked on a few Kubota engines, and I have never had a flywheel surfaced. And never had any trouble later.

But I would also suggest to replace the pilot bearing/bushing if there is one! You're there and virtually no cost.

Here's an easy way to get it out. Get a dowel that just fits into the bearing. Can be made out of any wooden round dowel you have. Fill the bearing with axle grease. Tap the dowel in gently with a hammer. Remove a couple of time to add more grease. Soon the bearing will be on your dowel.

If you want to keep things a little cleaner, try using Play-Doh instead of grease. Works like a charm!

 

[Lil Foot]

If you want to keep things a little cleaner, try using Play-Doh instead of grease. Works like a charm!

Never heard that one before! I'll file that away for future use, thanks!