Drug Kingpin

[farmersamm]

More like drugged kingpin:)

Pulled the spindle off the truck (with a little bit of effort;)), and found a surprise

There had been a previous installation. And it was done wrong. Maybe why it wore out??

I'm using a Stemco Kaiser "Plus" kit MADE IN U.S.A:blob3:

The previous installation was done with the same kit it appears.

But the parts were put in wrong

Bushing lip seals at outer end of kingpin (should be on the axle eye end)

Thrust bearing seal assembled on wrong side of thrust bearing, and thrust bearing installed upside down.

To be fair, the parts order can be confusing without the proper diagram. But a diagram is supplied with the parts. Or you can call the tech department. http://www.stemcokaiser.com/literature_install_pkpskr_01.aspx

I did in fact call the tech doood concerning a question about the thrust bearing orientation and thrust bearing seal orientation. I received a return call within 5min. :cool2: It's real nice to talk to an ENGLISH speaking tech person

Moral of the story.............Buy American, and read the instructions:waving:

[Rick V]

Wow... sure made quite a mess. Interesting post.

[dumb as a stump]

That there is a hum dinger of a big bugger.

[denrep]

Yeah Samm... but, if the kingpin was getting a shot of grease now and then, the improper assembly wouldn't mean much. After all, kingpins weren't even sealed, to speak of, for the first 80 years or so of trucking. In fact, I sort of wonder if the bushing being located a touch further outboard would help with handling heavy side loads and actually extend the set's life.

Good Luck

[Dualie]

those Stemco Kaiser Plus kits are the best on the market. Pretty much the only ones i will even bother with. I gotta go with denrep on the grease theory, if they got even a little love once and a while there would be no problem at all.

locating the bushing farther outboard causes twitchy steering, the old center point steering did that along with moving the wheel mounting flange inward in the days before power steering became std.

They pretty much had the center point concept dialed enough that even adding air assist to them made them to twitchy to be considered safe on the highway, at least in my opinion.

[farmersamm]

I think you guys have a point about the grease thing. Little luv woulda gone a long way.

The thing was a greasy mess when I pulled it down though.:confused:

The bushing that wore is in pic #3, the top bushing. It's the one which had the seal placed between the grease zerk and the bushing (it should have been between the bushing and the axle eye at the bottom of the bushing). Notice the tapped holes for the end cover. This is where the zerk is located.

The bottom bushing was in relatively good shape. The previous repair person didn't even install any seal in this bore, so the grease was free flowing from zerk to bushing to thrust bearing.

I know the improperly placed seal would have passed some grease. No seals are truly grease tight (most grease guns put out between 3-500psi I think). Most seals just keep dirt out while letting grease thru, otherwise you couldn't grease the bearing.

I do remember the old style kingpins. They had no seals. It was up to a good maintenance program to grease the thing, and force any contaminants out with the new grease. This is one thing I hate about sealed bearings.....you can't force dirt and water out of the bearing by greasing it:angry:

I'm thinking the improperly placed seal could of rolled out of its groove with grease pressure, and effectively partly or fully sealed the top bushing from grease flow. It is an o-ring type seal. The seal would have rolled against the top of the kingpin with nowhere to go.

Of note is a design change with the new kit.....the new style grease seal is a lip type seal, not an o-ring type seal. I don't know if this type of seal would self seal with pressure on the wrong side of the seal:confused: Something tells me the new design is even more "directional". Allowing grease out of the bore, while resisting any contaminant intrusion. It's absolutely trapped by the seal body, it can't roll