Can't get steering knuckle off Kubota B5200

[lslarry86]

Mowing roadsides yesterday, the left knuckle of my B5200 snapped off, where the long drag link joins the knuckle. I was about a half mile from the house, and couldn't see how to tow it with no steering. So I made this rig to get home. Worked ok, despite almost a full turn of lash in the linkage. But now I can't get the knuckle off. The exploded diagrams look like I should be able to loosen the pinch bolt and lift the knuckle right off, theoretically at least. I have watched the Pitman arm videos on youtube, so I know it can be tough. But this part looks like somebody peened the top of the shaft, or maybe even welded it. Do people do that?

Does this look like a weld to the assembled experts? Should I try to grind it? (click the thumbnail for 400x600 pixel version, look where the knuckle joins the vertical shaft)

Thanks,
Larry

 

[CalG]

Yes people do weld the like. And from the photo, It appears to be welded.

Take your side grinder to it, and see if you can see better when everything is clean and shinny. Filler rod will often display some contrast to the base.

If it is welded, just keep grinding, hope for shallow penetration ;-) Or if you wanted to be fussy, Pick up a Hole Saw/ annular cutter, the diameter of the spindle and cut the parting line. A pilot at the center of the spindle along with a firm and steady hand will be needed for this operation.

OH, Remove that pinch bolt completely, some spindles are relieved to allow the bolt to pass.

 

[lslarry86]

Thank you, Cal. I'll try it tonight after the garage cools off a bit and post results.

 

[lslarry86]

So things got messy. I ended up grinding through the knuckle and breaking it off in pieces. When I finally got to the spindle (aka 66681-56210 King Pin), I found it twisted pretty badly, with no key.

Does it sound reasonable that a previous owner lost the key and welded the top as a substitute? Maybe he turned right a lot. I have only had this thing for a couple of months, but it's about 35 years old.

Would it be reasonable to grind a new keyway around the back of this piece? Maybe take it all the way out and get it straightened at a machine shop?

Is the knuckle a wear part? Should I buy an extra now while they are still available?

 

[KYErik]

Perhaps he slid into a ditch/hit a tree with the wheel turned sideways and the sideways force is what twisted the king pin. There will be some wear on a joint at the end of a steering nuckle through the years, but if greased properly, a new one should last several thousand hours.

When he damaged the joint between the king pin and steering knuckle, he probably figured that he might as well try welding the two damaged parts together, versus buying new ones.

Obviously his repair held up OK. You need a new steering knuckle- hopefully that won't be too expensive. As for the king pin, I don't know that a machine shop could unpretzel that one (its not a simple bend)- If you aren't on a budget, I'd replace the king pin. If it was no longer available and you can't find one at a salvage yard, then I'd consider welding the new steering knuckle onto it. No- its not the "right" way to do it, but if you need the tractor ASAP, it is the most practical solution.

 

[Stimw]

I would look at the bottom of the king pin where it goes into the spindle to see if it can be separated.
If it can be separated then replace just the king pin with generic shaft.

 

[lslarry86]

Thanks for the suggestions. I don't see a way to get the pin out of the spindle at the bottom. Kubota shows it as one part. They may be pressed together. There is no obvious nut or setscrew.

I just went through a MAP canister and could not get the bent end hot enough to bend back, so it won't slide out. Erik's plan is starting to sound better.

Thanks again. I'll post final results next weekend after the new knuckle arrives.

 

[lslarry86]

Today I used a grinder to "untwist" the keyway, making one side more or less vertical. Also rounded off the kingpin top so the new knuckle would slip on. Hammered it all together including a new tool steel key and took it for a spin. Thanks for all your help!