How is Kubota B5200 steering spindle constructed?

[lslarry86]

My B5200 2WD tractor has had big toe-out since the folks here helped me fix a snapped left knuckle (aka "steering arm") last year:
https://www.tractorbynet.com/forums/parts-repairs/381143-cant-get-steering-knuckle-off.html

I have extended the tierod as far as it will go and have just been living with the problem.

Last week it got a lot worse, after I hit a stump while mowing roadsides. I barely got the tractor home. The angle of the right front tire was so radical it was almost rubbing the tie rod end in back, and steering was pretty weird. I have to think that the kingpin is slipping at either the top or bottom, but I can't see how in either place.

The top of the kingpin was welded to the knuckle, same as its neighbor in last year's thread. Even after grinding, I had to pop it off with a six foot dig bar. So I don't see a lot of slippage happening there. The kingpin is twisted similar to the one in last year's post, so it will not slide out of its socket in the front axle. I want to think the twist happened before I got the tractor last year. I guess it's possible that the kingpin twisted last time out, but the impact didn't seem that great to me.

The bottom of the kingpin has no fasteners, setscrews, or anything else maintainable that I can see. The spindle assembly is sold as a single unit. The exploded diagram shows one assembly, "29. Spindle" and I don't see a way to take it apart to realign it.

So does anyone know if it is possible to take the bottom of a Kubota B5200 2WD spindle apart and adjust its rotation, or should I just find a new one?

Thanks,
Larry

 

[zzvyb6]

Tube or solid ? Either way:

Heat it orange+ and bend (rotate) it back into alignment.

Cut and weld it back into alignment.

Is the knuckle a 2 piece parts with the vertical rod swaged into the elbow? If so, also heat and pound off, then back in with a pin.

(Blacksmith tactics).

 

[lslarry86]

Thanks for replying, zzvyb6. The kingpin is solid. I tried heat and twist on the other side last year and could not get it hot enough. Maybe if I could get the pin out of the axle there would be less of a heat sink, but it's twisted...

Is the knuckle a 2 piece parts with the vertical rod swaged into the elbow?

I think it must be something like that, but the parts manual doesn't break the "spindle" down into kingpin/axle/something-in-the-middle.

 

[Agvg]

This is probably a forged piece of steel, how is it twisted? Picture?

 

[lslarry86]

This is probably a forged piece of steel, how is it twisted? Picture?

This is from last year's article, linked in my OP. It's the left side. This year I'm working on the right side, but the twist is the same:

 

[rScotty]

This is from last year's article, linked in my OP. It's the left side. This year I'm working on the right side, but the twist is the same:

View attachment 560440

I don't see any way you are going to be able to untwist that kingpin and end us with anything decently usable.

It looks to me like you are in the market for new kingpin/spindles and new knuckles - probably on both sides. The welding "fix" was a decent try for a backyard temporary repair - but it didn't work. Are there bushings where the kingpin slips through the axle? If so, they need to be replaced as well. The amount of force necessary to twist that kingpin isn't something I'd expect to happen in normal - or even abnormal - tractor use.
rScotty

 

[lslarry86]

Hi, Scotty, thanks for that. I have only had the tractor for a year, and have no idea how the kingpins got twisted. The real problem right now is that the alignment is changing under normal use, so I think the kingpin is probably slipping at the bottom. The twist is a distractor to me at this point.

I have found a new spindle on ebay for $75. To get it in there I will have to grind off the top of the kingpin. I think before I go there I will:
* support the bottom of the spindle
* bang **** on the kingpin top to reset it in the bottom of the old corner
* grind a new keyway in the kingpin top and make everything smooth enough to reassemble
* put it back together with a tool steel key

Realign and see how long that lasts, with the new part in reserve.

If anyone thinks I am asking for trouble with that plan, I'd appreciate hearing about it.
Thanks,
Larry

 

[Agvg]

If the are made as it shows in the part list they are one solid piece of steel, they don't twist. If things adjust them selves I would look at the steering linkage.

 

[lslarry86]

I think the parts list drawing is oversimplified. Photo shows that there is a block at the bottom of the kingpin. I think the pin must be secured into that. There don't seem to be any bolts, so it must be pressed or swaged. Probably not splined, unless the splines have stripped. I'm thinking whatever twisted the kingpins also knocked the spindles out of alignment. The left one has lash - as I turn the wheel, the kingpin turns right away but the axle does not start to move until the pin has rotated 5 or 10 degrees. New spindle coming, more next weekend. Thanks!

 

[lslarry86]

I was lucky enough to find a new spindle on ebay, which fit. It took a wheel puller to get the bearings off the old taper. I used a 3 ton arbor press to set the bearings on the new spindle's tapered axle, but I think you can do it by threading the castle nut too.



The original question is, how is this thing constructed? The corner is cast. The kingpin and axle taper are pressed in. The end of the kingpin is protected by some material, maybe epoxy. It could be welded, but it cut easily on the drill press.