Kingpin preload

[t56tr]

I have a 54 3b - assuming it is the original front axle...

I am rebuilding the front axle.

On drivers side I am reusing everything, but installing new kingpin bearings and wheel bearings.

On pass side it needs new knuckle, spindle, axle, hub and new kingpin bearings and wheel bearings. For this side I bought an omix knuckle new, reusing old kingpin caps.

Question about the preload.

1) It has been a while since the tear down so I forgot if the bottom kingpins had shims. So, I just set preload with shimming the tops. It didnt take many shims on each side (drivers and pass), maybe approx 50 thou.

Question is, is it ok to shim only tops, or should I be shimming top and bottom?

2)I didnt have a scale, so originally I tried to set the preload by feel. I set each side to what I would describe as pretty tight feeling - ie, you could not just slap it with your finger tips and move it, you had to pull or push it with a little force.

I decided to go to fart mart and get a scale. When I checked my preload it is about 6lbs per side.

If I am correct, I have read that it should be 10-14?

I can de-shim and bring them up to that, but I am assuming that it will feel rediculously tight, is that correct?

PS The readings are with no knuckle seals/tie rods etc, but I did pack/grease the bearings for testing. Also, I checked the scale by weighing a gallon of paint. 12.5 with the fish scale, 13 on a bath scale, so Id say the fish scale is accurate enough. I had the scale in the tie rod hole of the knuckle for tests.

Thanks

[Rus Curtis]

t56tr,
In my Service Manual, Section M Front Axle, it describes the Pivot Pins (Kingpins) not having lower shims after the CJ2A model. It states that starting with the CJ3A model, .058" was added to the lower shim face eliminating the need for shims on the bottom.

You are smart to get a tool to measure correctly your preload. For the same reason you use a torque wrench to torque bolts, you need a scale vs. trying to figure it out "by feel." As you found out, it isn't the same.

My SM indicates preload should be between 12 and 16 lbs. No seal from the knuckle tie rod arm just like you did. The reading you want is just as the arm begins to move.

Remember this is for your jeep's preload, not your "by hand" feel. When assembled and working, your steering will be even tighter due to the seals also. However, the steering wheel, the steering box and the other steering components give you a mechanical advantage that will easily overcome the tightness. This tightness needs to be there to avoid this component developing/contributing to shimmy.

I like your technique of greasing the pivot bearings. I did this also.

[t56tr]

I got them tighter to about 11 lbs and left them at that (which seems pretty darn tight).

I had two new discoveries.

On one side I distored the cage on one of the bearings by using a bolt that was too long... I was doing my tests with out the hose plate installed and that little bit made the diff on that side.

On the other side I realized I forgot to polish the ball on the axle end (the knuckle seal surface). I took the knuckle off, removed the cages and cleaned all the grease out of the bearing cups so dirt wouldnt stick when polishing.

Would you belive that the cups already showed very slight contact marks from the bearings. Nothing you could feel but you could see discoloration marks the shape of the bearing rollers. Wonder what it would look like at 16lbs.

Anyway with the seals on it reads 22lbs.