Cub 149 steering knuckle sheared off
 

Cub cadet 149
The spindle/axel on a steering knuckle sheared off... tire fell off leaving the piece in the tire and broken off flush with the knuckle bracket. Any idea why it catastrophically failed?

I'm going to replace the the entire steering knuckle assembly..hopefully I can find one.

Is there bushings or something else I need to check or replace?
Is this repair as simple as just swapping out the knuckle bracket?

Operator abuse, lack of proper lube and/or wheel bearing adjustment and lube.

Check the parts books for an exploded view.
That will answer all your questions.

In regards to the wheel bearings you mentioned, what is the adjustment procedure? I never done anything besides shooting grease into the zerk, and lubing up the spindle portion of the knuckle, when I have removed the tire.

The 149 has been around a long time, and guessing you are not the first owner, so you have no idea if the usage.
Anything from gentle usage just mowing a smooth lawn to front loader abuse.
the spindles are inserted in the stamped then formed bracket, and welded to it on the inside stub.
we have no knowledge of the quality of the weld, the conditions of it at time of manufacture or how the molecular structure was disturbed by the welding.
Most all spindles work just fine, obviously this one failed.
it could have caught a tree, the corner of a building, some youngster doing "wheelies" etc etc.
We could speculate for many lifetimes the "why" it failed.
They did see the need to go to a larger 1" spindle in later models.
possibly they also used different material for the shaft itself or changed the welding process.
Did it break off leaving a short "stub" in the formed bracket, or did it fail at the point where it was welded on the back side at the end of the stub?
Actually, it doesn't matter, it is "done broked" as is said :bash2:

There is no "adjustment" as such for the bearing, like on a vehicle with a spindle nut & cotter key holding the hub/brake drum or disc to the shaft.
Just replace it and don't buy a lotto ticket for a while. :biggrin2:
You are actually lucky, as it could have decided to divorce itself in an event that was dangerous, or quite embarrassing with 50,000 spectators watching. :bigeyes:

Your right george, its broke.. no need to speculate. Fwiw it snapped right at the weld, flush.

Getting a closer look at damage this morning. The bearings in both wheels are spinning freely, likely the originals or very old... should the be repacked or replaced?

Lucky i got it out of the pasture before heavy rain.. i would had to fix it in the muddy pasture. I was able to use a hand truck/dolly under the broken corner. Its high and dry in the garage now waiting for repair.

Replace all four bearings. Probably way past time.

On the wheel bearing adjustment....

Check the service manual
GSS 15464 w/revision 2
2 Sept 1974 Page 2-15

Pressure from the wheel nut securing the large thick washer must be on the outer race.
If a shim is needed and the washer tightened down on the inner race you will destroy the bearing in short order.
Hence the need for a shim if needed.
Many Cubs that have come across my table have needed the front bearings shimmed.
IMHO, bearings should be serviced yearly, cleaned and repacked.
Was normal maintenance for cars "back in the day" as well.
On of the first things many folks my age learned to do as kids hanging around a garage.

I'm running into the shim issue right now myself. Put in new Stens bearings and they must not be as thick as the OEM bearings, or the flange is thinner. With the washer installed and nuts tightened, the wheels have at least 1/16" of endplay on the spindle.

How can the large washer press against the outer race? The outer race rotates with the wheel, while the washer is fixed to the spindle. It seems like the only way this can work properly is if the large washer (or shim) touches the inner race and clears the outer race. Isn't that why the inner race protrudes out slightly more than the outer?