identify kingpin washer

[bcjm]

I took my kingpins to a machine shop asked them to fit it for me.  One side needs to be replaced for sure and someone had done the other side before so I asked them to check for me.  They told me the other side is in good shape so they did only one.

I took them home and tightened the end nut to 65 lb-ft on bench.  The one they did can't turn and the good old one turned fine.  I removed the lower carrier from both.  The one they did have a washer inside the carrier housing (photo 1) and the old one did not. Is this the compensating washer?   There IS a washer fitted to the brass bushing inside the steering knuckle on both kingpins (photo 2). Is that the compensating washer?  

Photo 3 shows the new kingpin kit.  The round washer on the left most is bigger than the other two (all have different thickness).  Are the other two the thrust washers?
Can someone tell me exactly which one is the compensating washer?  Was my old "good" pingpin installed incorrectly?



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Download Attachment: kingpin_washer.JPG
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Download Attachment: kingpin_new.JPG
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[BHap]

the compensating washer goes on the bottom of the kingpin setup, between the lower trunion and the bottom of kingpin bushing.  it sounds like your old one wasn't installed properly (be sure the washer isn't just stuck to the bottom of the kingpin bushing).  the new kingpin setup needs a thinner washer, or more likely, the washer needs to be sanded down until the proper amount of torque on the bottom nut still allows the steering knuckle to turn freely.  There are also specs for the up and down free play on the kingpin - which is what the compensating washer is used to adjust.  I torqued mine until the steering knuckle started to bind, then sanded the thinnest washer until the kingpin/steering knuckle turned without resistence and the 65 ft lbs of torque on the lower nut.  doing this on the bench saves a lot of hassle...  be patient and get it right or the steering will feel dead and not return to center as it should....

Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed

[BHap]

the washers in the picture appear to be - from left to right - thrust washer, compensating washer, compensating washer and thrust washer.  the two thrust washers are much heavier than the compensating washers - the kits usually come with three compensating washers of differing thickness.  You only use one of the compensating washers on the lower end and the two thrust washers on top.  be sure to seat the lower thrust washer with the grease grooves pointed up and the washer seated correctly on the pin on the top of the kingpin housing.

Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed

[bcjm]

Two thrust washers go to the top and one of the compensating washer goes to the bottom according to the book.  The left most washer in the picture is bigger and thicker than the two on its right.  Are you sure that is the thrust washer?  If the two smaller one are compensating washers then one of them needs to go to the bottom then.

[BHap]

Yes - from what I see in the picture, the left most washer is a thrust washer - the other thrust washer has the grease channels.  Both of the thrust washers are much heavier and seem to be hardened steel...  the compensating washers are much thinner and can be "easily" sanded down to fit....

Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed

[bcjm]

1. How do you "sand" a washer?  So hard to grab not to mention sanding it.
2. Is there a special way to line up the upper and lower control arms with the kingpin?  Lifting the bottom control arm up and down does not seem to do the trick.

[enochbell]

bcjm,

I just went through this repair, so I will try to help, but please read bhap's first note, it is spot on and will help you understand what is going on with the king pin.

I had trouble sanding the compensating washers, I was luck enough to get one that worked for me from my local independent.  The trick is to use a compensating washer that is small enough to allow a tiny amount of end play (the BBB specifies the amount of play, but I found it impossible to measure: the key is to make sure there is enough to prevent any restriction in the axial movement) in the king pin, after proper torque is applied to the retaining nut.  This will be by trial an error on your bench.  Once you have that set up properly take it apart and install it in the control arm.  The book would have you use a special alignment tool to line up the upper and over bushing carriers and then install it, but I took a shortcut and installed the bushings (lower first) along with the king pin WITHOUT tightening the lower retaining nut.  Once assembled I then torqued the nut.

Hope that helps,

g

'64 230sl, fully sorted out...ooops, spoke too soon

[BHap]

I used a pair of old leather gloves to use while sanding - helped keep the ends of my fingers from rubbing the sand paper. I used coarse sand paper - 100 grit until I had removed enough material, then finished with 320...  Be sure you are starting with the thinnest washer...  it is a tedious job, but not one you want to compromise on...  Mercedes shows about 6 different sizes for compensating washers so if you have a way to measure the thinnest one that is still too thick - you might be able to buy the next couple of smaller ones from Mercedes  - but I'm not sure if they are available.

Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed

[bcjm]

I put two thrust washers on top, with no compensating washer, the kingpin locked up with little torque.  I have to use one of the smaller/thinner washer on top, with no compensating washer to torque to spec.   Is this safe?  The machine shop says it is fine.

[BHap]

thrust washers are hardened steel, compensating washers are soft - it will not wear, or work correctly... something isn't sitting properly...  there is a very small guide pin on the top of the kingpin "housing" - where the upper bushing is pressed in - where the thrust washer sits.  This pin is very soft - brass? - and can be easily crushed if you assemble the kingpin with the lower thrust washer in the wrong position.  There is a small cutout on the lower thrust washer where the guide pin is supposed to be located.  If you can't see the guide pin, look for a small "nub" on the surface where the thrust washer sits - (ask me how i know) - if you've crushed it, take a chisel or other "crafting" tool and try to get it back into some sort of shape so that the thrust washer sits perfectly flat...  another thing to be sure of is that you are only using a very, very thin amount of grease...  the tolerances/torques on the kingpin are in thousandth's of an inch...  if you are not successful in getting the two upper thrust washers in position with the thinnest of compensating washers, I would try to find an independent mechanic familiar with the old kingpin setups and have him take a look - it is not worth putting together wrong and regretting it...

Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed

[bcjm]

I paid extra attention to the pin on the top.  The thrust washer sits correctly.  Is it possible to use one thrust washer (the one with grease grove) and one compensating washer instead of two thrust washers and no compensating washer?

[BHap]

the thrust washers are designed to work together, they create the "joint" that actually pivots the weight of the car - I would not use a compensating washer on the top - do it right, do it once.

Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed