The Stovebolt Site Forums The Shop Area Engine Shop KING Pins

Well, what I thought was just loose wheel hub nuts turns out to be a little bit of play in my king pins. The top of the king pin housing can move in and out approximately 1/8". Is this cause for concern? I do not know if it is worn king pins or the I beam front axel. I looked it up in my 1946 Chevrolet repair manual and it mentions a bushing but does not say if there actually is a bushing in all models or not. I see Jim Carter sells .010" oversized king pins.

Who has replaced king pins? Is it a real nightmare? In your opinion, do you think mine need to be replaced or is there always that much play in them? I'd hate to change them and there still be the play in them.


My current frame of mind is saying to leave them alone and once the truck is on the road see if it causes issues and replace them then. But on the other hand, they are so accessible right now.

Think about it, 1/8" is 0.125". a .010" oversized pin isn't going to make a difference. I don't know anything about king pins, I just see numbers.

That is at the very top of the king pin. The 1/8" play is closer to the mid point where the I beam axel and the wheel hub assembly meet.

My tires are California Racing Mags which are a good 10-12" wide so the king pin play may not even be able to tilt these tires/wheels unless I'm doing some hard cornering I would assume.

Just don't drive on roads with ruts. There is a tech tip on this I think, and if you do a search, many people have replaced theirs. I don't believe that there should be too much play.
I believe that when you replace the kin pins, you also replace the bushings they go through.
I bought a set, with bushings etc, but have not put them in yet. Rebuilding the front end, is my last (yeah right) big job left on the truck. Someone else will chime in with more experience.

1/8-inch at the king pin seems like a lot of free play to me. With the front tires installed, and the front of the truck jacked up, grab each tire with your hands at 12-o'clock and 6-o'clock. Rock the tire back and forth. If the surface of the tire at your hands moves more than about 1/4-inch, your king pins are worn out and should be replaced. Think about it. Every time you turn a corner or reach highway speeds, that much free play will translate to stability problems and safety issues.

The hardest part about replacing the king pins is getting the old ones out. One of mine popped right out and the other I needed to take to a machine shop to press out. After that, it's an easy weekend job. Most of the truck vendors (and probably local auto parts stores) will carry king-pin replacement kits. The kit includes a new pin and a new bushing above and below the axle. The bushings are usually what wear out and cause the play. Under severe conditions (previous owner did not grease the axle), the hole through the axle can also be worn. This is more difficult to fix because the hole might need to be machined and you might need to use the oversize king-pins.

I agree with Norcal49er, In our chassis class last year they told us king pins should not have more than .115 of vertical play and that king pins will also have a minimum of 2-3 degrees of scrub radius(vertical angle in degrees the king pin sits). Depening on the type dont forget about the locking pin. There should be a tiny pin halfway up the housing of the actualy king pin itself. knock it out with a screw driver or what ever will fit. Then knock the pin out. good luck.

Getting pins out can be as easy as tapping them out or as hard heating the axle red hot and using a pin press. You can never tell if one side will almost fall out and the other never comes out. Your best bet is remove the axle and bring it to a good automotive machine shop.

Completely agree

Did mine like this.
1- Removed the Axle
2- Had it sandblasted (didn't care about rust... I painted with Por-15)
3- Took to NAPA (They pressed out the old pins & installed new bushings in the knuckles)
4- Painted
5- Installed new kingpins and keeper pins (Be aware that the keeper pins are made to go in only one way. Made this mistake and tried to force them... That wasn't fun)

NAPA ordered the kingpin set... The set plus labor cost around 120 bucks (Pin set was $90 if i remember right, making labor $30)

Did the King pins on my '50 half ton earlier this year -it's a straightforward job, as others have said, getting the old kingpins out can take a bit of time, and may need some heat on the axle eye as you press or drift the old kingpins out.

You will only need the oversize kingpins if the Kingpin hole in the axle beam has become worn due to the nuts on the kingpin retaining (cotter) pins being allowed to come loose. Then you would need to ream out the axle eyes to accept the oversize pins -I would try and find another axle setup to work on if I had this problem.

The kingpin set comes with all the parts you need. The Moog (Federal Mogul) part number of the kit for the half ton trucks is 8294B. Your nearest NAPA should have these, but I found that they were cheaper from Jim Carter or Classic Parts of America (Chevy Duty).

Stuart.

drivers side wheel on my '52 had alot of play.ordered new pins before i took it apart and after it came apart,easy,i knew it needed oversize pins.put the standard in,daily driver,just did the one side and ordered oversize and adj. reamer.easy 2 hr.job and perfect tire wear with no pull,easy to do front end align.with tape meas.and string.a good align.shop has oversize pins of diff.dia.