Kingpin suspension confusion

[todds]

I've been trying to disassemble my kingpins and am running into trouble separating the upper control arm outer hinge from it. The big nut on the rear was easy to take off, as was the little nut on the front and the lock plate. I could easily rotate the camber adjustment via the larger front bolt (after paint marking the original position) I figured I should just keep rotating it to get it out, the glenn manual I have is unclear on this part, however when I do this the kingpin itself seems to just screw fore and aft inside the control arm bending the "tangs" of the arm slightly. I didn't turn it too far for fear of braking or bending something permanently. I can see that the caster adjusting washer with the little notches in it rotates with the rest of it. I tried holding it steady with a flathead but either it's frozen or that's not how it works. Can anyone shed some light on how this happens?

[Tomguy]

The eccentric bolt can lock up inside the kingpin due to rust, lack of grease, bending, etc etc. Happened on mine, I had to cut the eccentric bolt and then replace the whole kingpin and eccentric bolt assembly.

[todds]

Well, I think the eccentric bolt is rotating, at least the camber is changing when I turn it and it doesn't bind up. What's puzzling is the way it goes together... There is a threaded shaft which threads into the top of the kingpin itself which the eccentric bolt appears to turn too. Does the eccentric bolt go THROUGH this shaft somehow? is the threaded shaft hollow? How would it normally come apart if everything was okay?

[Tomguy]

The eccentric bolt goes through a threaded bolt/tube/whatever. That threads into the kingpin. This is part of adjusting caster. The threaded bolt can control caster. The eccentric bolt controls the camber.
http://www.allpartsexpress.com/ShopByVehicle.epc?q=1972-MERCEDES--BENZ---80se--4.5--/--V8--45--0cc--4.5l--Gas--Fi-Front--End--/--Suspension--Steering&yearid=1972%40%401972&makeid=MERCEDES+BENZ%40%40MERCEDES+BENZ%40%40X&engineid=1194634%40%40280SE+4.5+%2F+V8-4520cc+4.5L+GAS+FI%40%40280SE+4.5&catid=Front+End+%2F+Suspension+%26+Steering%40%40Front+End+%2F+Suspension+%26+Steering&subcatid=Fr.+Control+Arm+Eccentric+Kit@@Fr.+Control+Arm+Eccentric+Kit&mode=PA

[todds]

Ahh, thanks, that clarifies it. So what has happened is that the eccentric bolt is indeed frozen as you've said. The threaded hollow screw is not frozen in the kingpin however and neither are the ends of the eccentric. What is frozen is the center of the eccentric to the hollow portion of the screw AND to the caster adjuster. I suppose what I can do is hit it with as much PB Blaster as possible and heat up the threaded portion and caster washer then put the big nut on a few turns and pound on it with a mallet. It is supposed to just slide out towards the front.

[Tomguy]

Do this instead:
Cut the bolt.
Thread the hollow screw out.
Buy a new eccentric kit.

Your life will be a lot easier doing it this way, if you have a sawzall w/a metal cutting blade (mini hacksaw blade), or a hacksaw. I couldn't get a Dremel in (it was too deep). Trust me, if that bolt's frozen inside, it's probably not coming out.

[todds]

Yeah, I like the sawzall... sounds fair enough.

Now that I know how it all goes together, I still can't visualize where the actual pivoting takes place when it is operating correctly. When the car is hitting bumps, is it supposed to be pivoting about the threads or about the eccentric shaft?

If it's supposed to pivot around the shaft with the threads remaining fixed, then where does the sliding take place end-to-end? Do the castor washer and rear flat washer stick along with the kingpin and slide on the ends of the eccentric or do they stick along with the ends of the eccentric and slide along with the rubbers seals and kingpin?

I guess it's confusing because it seems like the bottom hinge pivots along the threads as well and slides against the seals.

[Tomguy]

The "Pivoting" from bumps is the threaded part inside the UCA. The eccentric bolt moves the wheel vertically which is camber. The threaded part can go back or forth inside the UCA which controls caster (the angle at which the wheel turns, varying camber at different turn angles).

[todds]

Yeah, that's what makes the most sense to me from looking at the drawings and considering the way my car was frozen since it still operated correctly for the most part.

Since it actually pivots on the threads both top and bottom, doesn't that mean the knuckle moves slightly front-to-back when you hit a bump or pothole? I guess the caster adjustment is pretty slight and depends on the pliability of the rubber seals somewhat.

[todds]

doesn't that mean the knuckle moves slightly front-to-back when you hit a bump or pothole?

Waiiit a minute, do the inner control arm bushing threads screw in the opposite direction of these outer pivots?!? If so that's genius!