Throwout Bearing Observation

Sun Jun 06, 2004 8:03 pm

I've been thinking about this bearing situation and come up with an observation. First off, I have never used, or even looked closely at a ball bearing "Bates" type bearing. I can't comment either way on whether they use a thrust type bearing or not. If not, that was a serious mistake that should have never happened.

However, there is another fundamental problem besides the type of bearing used. Every ball bearing type throwout bearing that I have ever seen is supported either by a stationary hollow shaft attached to a housing or a sleeve that rides on the clutch shaft. Either way, the throwout bearing is held exactly on the axis of the crankshaft. The Cub linkage inherently does not do this. Even if the Cub clutch release yoke is in perfect condition, the movement of the bearing will be through an arc, not on the straight line of the crankshaft axis. If the yoke is worn or bent, the throwout bearing will be farther away from the crankshaft axis. If the bearing is not centered on the crankshaft axis, the face of the throwout bearing will be moving on the tips of the clutch fingers. The worse the alignment, the greater the movement. Since this is pure steel-on-steel contact, it will not be good. The heat from this friction may be contributing to failure of the bearings themselves. The worse the alignment, the quicker it will overheat (and the more bits of metal fall to the bottom of the bell housing).

The graphite bearing won't be bothered by being a little off center, nor will it matter that the motion is through an arc. I think the only way to put a ball bearing throwout bearing in a Cub is to turn a section of the clutch shaft and add a bearing holder supported by the shaft.

Sun Jun 06, 2004 8:30 pm

I had been thinking on the same lines, but hadn't come up with the right way to express it. The face the clutch fingers contacts is fairly thin and not very large. It doesn't leave much room for error. The sliding of the fingers on the face due to misalignment would be small, but could cause a problem. I think mine failed due to a faulty/wrong type bearing. It failed after after about 2 or 3 hours of moderate use, and when I removed it the bearing turned smooth, but was stiff. I think the clutch fingers were just sliding on the face.

Sun Jun 06, 2004 10:34 pm

Jim ,John, Cub-Bud .Took out T.O.B(Bates type) from my tractor this weekend.Face of Bearing worn completely off.Will see if I can get apic of it tomorrow and post it here before I send it back to Bates.They sent me a replacement but I installed a Case/IH one graphite one.Will keep you abreast on what happens next.My Bearing moves in the yoke ,I can move it fwd and aft (stiff) Bolt tight in yoke.Yoke does not appear to be worn or bent. Old bearing housing had chaffing and worn pins.My observation of the clutch is the same as yours Jim the arc pendulum swing of the it hits the face of the clutch fingers.It was like a meat slicer at the food market."How thick did you want that turkey", sir.

Sun Jun 06, 2004 10:52 pm

The IH graphite style bearing lasted 40, 50 + years (maybe more on some). Why all the discussion to change to a true roller bearing?? The mechanical alignment problems that Jim points out are only the beginning.

If you are truly "burning up" a graphite T/O bearing, maybe you need:

1. A new or a stronger clutch pedal spring.

2. Learn how to "drive a stick" and not "ride" the clutch pedal.

3. Buy a Brand X with a hand clutch and never have to worry...

4. Not own a tractor.

In 50 years from now when the next owner is doing a clutch replacement and finds that they have the B.T.O.B. inside, where are they going to find parts for it?? Not at any IH dealer as it not in any Cub parts book anywhere. This may sound "harsh" but the graphite bearing design served IH well for the life of the Cub, why change?

Mon Jun 07, 2004 4:54 am

Well, my Bates TO Bearing has been in for over a year now with no problem. I have taken off the access cover and found no evidence of metal shavings - yet.

I guess that it is living on borrowed time. So, I am going to buy a new graphite bearing from IH and throw it into the shop until the inevitable happens.

I installed a Bates because I had read so much about graphite bearing failure not realizing that the culprits were not of IH origin.

Bates had a good idea. I guess if people didn't try new and innovative concepts, we would still be riding around on wooden axles lubricated with animal fat. That worked just fine for several thousand years instead of just 50 years, but I sure don't relish the idea of having to split the tractor again.

Mon Jun 07, 2004 9:17 am

Rick ('50, NC) wrote:Well, my Bates TO Bearing has been in for over a year now with no problem. I have taken off the access cover and found no evidence of metal shavings - yet.

I guess that it is living on borrowed time..
If it hasn't failed by now I wouldn't worry aobut it. when the Bates type bearing first became available everyone was happy with them. I first started noticing complaints about them late last fall on the different lists. I strongly suspect that the manufacturer made some changes, either a different type bearing, the way it is mounted, or maybe even different people assembling them, that has resulted in the flurry of failure reports. All the failure reports I've heard have happened during the first 4 or 5 hours of use.

Mon Jun 07, 2004 10:11 pm

Ran cub when I got home from work today.Approx. two hours ,back and foward.With new Carter and Gruenwald orig. Case/IH T.O.B graphite (like the plug Ken!) No wear to face of bearing.No residue in Clutch housing.Works great, Hey I learned my lesson here. I also know this was my only problem I had in this restoration.I have to thank all of the board members and there inputs for this really was fun.Maybe sombody learned somthing from me, this is what it's all about