Steering knuckle failure

[gwdixon]

The guy I sold my L3650 to 4 months ago called today to say the right front steering knuckle had snapped off where rod attaches to the housing.

In looking at it, there was a clean break where the bolt on the rod attaches to the hub. It will cost $1200 to fix. I don't recall hitting the tire or wheel with anything that would remotely cause such a failure.

Did a search and came up with nothing about this problem. The early Hummers from GM had this same type of problem and were recalled if I remember correctly. Anybody know anything about this issue in a Kubota?

I'll try to get some photos if anyone is interested. Thanks for any information or insights.

 

[jlrsn]

A person had her Kubota Front Axle Casting Break while mowing: Complete different machines but.....:

(http://******************.com/kubota/1959-kubota-manufacturing-plants.html)

Substitute "machine-under-ground" without the dashes for the ********* above and right after "kubota" replace "manufacturing-" for the "ing". TractorByNet does not allow the competition to be posted

Good luck,
Jim

 

[jlrsn]

A person had her Kubota Front Axle Casting Break while mowing. I'll send you the URL as a PM as every time I try to put the URL in it gets unreadable by TractorByNet
Good luck,
Jim

 

[gwdixon]

Thanks jlrsn.

Attached are photos of the problem. It appears that the force would have had to come from above or below to snap off the attachment point.

 

[dfkrug]

Wow, GW, that's quite a failure. Thx for posting.

The good news is the tractor is old enough to make finding a used part
at least possible. If I were the owner, I would find out what other tractors
use the same part, too.

There is also little risk to trying to grind some serious chamfers and welding.

Also, those MFWD hubs are not hard to take apart.

 

[SockPuppet]

My first post here!

It looks like the piece was already cracked from the pics and I'm going to guess the tie rod end was over-tightened and wedged the first crack in.

 

[ultrarunner]

I once got wedged pointed downhill between two trees... no matter what I tried, the front tires just deformed and wedged tighter... my first thought is something is going to give and it won't be the trees.

Ended up using some chain and a chain fall to extricate myself...

 

[Adiredneck]

My neighbor had the same break a couple of years ago with his 1992 L3450. He figures there must have been a pebble or something that got wedged into the knuckle & cracked it. Part of the break was rusty, and part was not, so it had been like that for a while.

He unbolted the housing, took it to a machine shop and they welded it for him. The machinist mentioned that there was a high nickel content in the cast and it welded easy. It was a cheap fix for him and he uses his tractor almost every day.

 

[gwdixon]

Thanks for all of the replies and suggestions. Your collective wisdom will be forwarded to the owner.

Grinding a chamfer and doing a 100% weld on that casting would be quite a feat - far beyond my skills but it is nice to know of the possibility of having a machine shop or welding shop do it.

The pictures show a slight discoloration on the upper portion where the tapered bolt goes through the casting. Maybe it was an existing condition or had been cracked for some time. There is no rust in the discoloration however. (The surface rust on the fresh break is from an overnight rain.)

The owner had it hauled to the local Kubota dealer today for a brand new casting. I called and asked him to have them save the old parts. It will likely never break again but it might be interesting to try a "farmer repair" on it just for practice. The taper could probably be re-machined by a machine shop.

 

[Adiredneck]

GWDIXON:

$$That's gonna hurt! Cast is not something I am capable of welding either. My father broke a cast pulley last year on an old IH 300 Utility. He removed it and a friend vee'd out the edges, clamped the pieces together, heated them and did a darn good job reairing it. It's working good. He also welded a broken ATV axle for me a couple of years ago. He welded a little bit, then walked away for a 1/2 hour, then another pass, repeat... Came out good and true.

Too bad your friend couldn't have tried to do a repair first, before paying to have it all replaced. There's not much to taking it apart to bring to a machinist.

I like the picture in your Avatar.