The Stovebolt Site Forums The Shop Area Driveline Kingpin/bushing question

I'm currently working on my steering on my '53 Chevy 3100 1/2 ton. I've replaced the tie rod, tie rod ends, new ball studs on the steering arm and pitman arm, and have a new kingpin set from LMC that I'm replacing.

My question is how much play should I have with the spindle and the kingpins? I feel like I have a lot of slop. I'm guessing grease alone is not enough to make it tight. Would it be worth it to take my spindles to a machine shop to ream out the opening, and then make me some new oversize bushings?

The short answer is none. You should not have any slop in the kingpins.

I just went through this on my 58. It felt like there was just barely enough movement to feel when I replaced the wheel bearings, so I lubed them up and put it back togetheonce I worked the new grease around and into the bushings, they got extremely floppy.

When I pulled them apart, the wear was 75% on the bushings and 25% on the kingpins themselves. I did not have to ream them for oversized bushings and they have zero play now.

Check your service manual about reaming. The TF 3100/3200 trucks do not require reaming the new bushings, but the larger ones do. I don't know about the AD setup offhand.

The one issue I ran into with the kingpin kit I got from Speedway was that it didn't have enough of the right size shims for me. The details are in the link in my signature, but my gap was too small for the thick shims and too large for the small shims they provided so I had to get some extras. Even with the extra shims, they were still cheaper than LMC and they had it all in stock.

Just trying to make myself clear for everyone to figure this out. I understand my truck should be just a slip fit for the bushing's and not have to press them in. My question was to wether to have the spindles reamed out to accept an oversized bushing. Not to ream out the new bushings. I understand they are already reamed for fit.
Here is what I currently have:

Old kingpin measures .877 inches
New kingpin measures .866 inches

Old bushing measures 1.05 inches outer diameter; .866 inches inner diameter
New bushing measures 1.05 inches outer diameter; .860 inches inner diameter

Spindle opening measures 1.05 inches inner diameter.

Hope this helps!

Something doesn't add up there. Your old kingpin OD is 10thou larger than your old bushing ID.

That aside, if the new bushing OD is correct for the spindle ID what would the reason be to ream it for oversized bushings?

The service manual for the 58 said to press the new bushings in with two thumbs (lubricated with lard) and if they were loose/fell out then ream the spindle for oversized bushings.

I don't see any indication that you have an issue?

Edit: is it possible that you are measuring the dirty surface of the old kingpin and that is affecting your measurement?

Doug, Your measurement for the "old" kingpin of ".877 inches" most closely matches the dimensions for a .010 OS (oversize) kingpin set. An original GM .010 OS king pin replacement kit (GM# 609882) shows the king pin dimensions to be .876" X 5.31" long in the Master Parts Books. Trying to replace an already oversized king pin with the original smaller diameter king pin will leave you with an even worse wobbly condition. If the king pins are sloppy with the old kingpin and bushing set, where exactly is the slop? Is it in the bushing to pin fit, or is it in the pin to axle bore fit? I would suggest you check the fit of the old pin in the axle shaft hole and see how tight/loose that fit is before moving on with more questions.

I would also mention that the math doesn't seem to work with the old pin diameter (.877 inches) and the old bushing inner diameter (.866 inches). The pin wouldn't fit into the bushing if the inner diameter of the bushing is smaller than the pins outer diameter. A typo perhaps?

Edit: Fibonachu beat me to the punch on this last thought.

Sorry guys don't know where that dimension came from. Just re-measured and came up with .88 for the inner diameter of the old bushing. After reevaluation, I think I misinterpreted what I thought was play in the kingpin/bushing to probably needing a shim between the knuckle and the main bearing. I'll see if I can find one that works and report back to you all.

There should be a thrust bearing on top of the knuckle (under the axle) and a shim between the top of the axle and the bottom of the knuckle. The spec for the gap at the top is 0.005" when lifted from the bottom to fully compress the thrust bearing. I strongly suspect that by the time you get it far enough apart to add a shim, you aee going to find it to worn to safely out back together.

I am sending you a PM about some parts.

I apologize guys for the delays. I came down with Covid for a short while, then the holidays hit. So I ended up putting in two thin shims, totaling .135 in to get the knuckle very secure. I just assumed that kind of play came from inside the king pin shaft on the knuckle.

Thanks to all that replied!

When I took mine apart, all of the play was from wear on both the pin (1/3) and the bushings (2/3). Putting in a new kit got me nice and tight.

Sounds like yours did too.

Out of curiousity, what disk brake conversion do you have on that?

I'm actually not sure. I bought the truck and had the conversion already done. I can get you better pictures of it.

Looking at your picture, is your hub/rotor seated properly? It sure looks like the seal is just kind of hanging out there with a pretty big gap to rotor. I am worried that either your wheel bearings are not seated properly or the back side is open to the elements.

Either one would cause rapid wear and failure.

Thanks for pointing that out! I see what you mean. How can I ensure that the bearings/hub get seated properly?

How mechanically inclined are you?

I can't tell from the pictures what the overall problem is. It could be that just the seal got dislodged during removal/reinstallation and the rest is fine.

I would start by taking the hub/spindle off and reinstalling the seal. Then you can look at the bearing surfaces and bearings and make sure that everything is in good condition and lines up properly as you install it.

Do you know how to do wheel bearings in the general sense?

Well, I'll certainly give it a shot and check back with you guys.

I finally got around to pulling the hub back off. Found the rear seal improperly installed. Hope this looks right.

That looks much better.

Were both sides installed incorrectly? This picture is the passenger side and the earlier picture was the driver side.

Correct, both hubs pulled off and corrected. Just the side I took the picture from.