The Stovebolt Site Forums The Shop Area General Truck Talk king pins & front axle

Looking for some help. Changed the kingpins in my '53 chevy 3100 and thought things were alright. Everything felt tight when I finished. When I went to get the front end aligned I was told the kingpins were bad. I knew this was incorrect since I had just changed them less than a 100 miles ago. After checking them again, I found the axle bores were a little big for the pins. Not much but enough to show a little play. I've read about oversize kingpins. I know I need to have the axle and spindles re-bored. Has anyone experienced this problem. What can I do and where do I find the oversize pins and bushings?

blkhrn,

I don't know how your luck runs, but maybe your truck already had oversize kingpins in it and you put standards back in when you did your work...not that lucky!

The best bet would be to go back to the store you purchased your last set from and get a oversize set.

The axle eye will have to be bored to accept the oversize pins, but the spindle, being a 1/2 ton should just be hand assembly.

Oversize pins will come in several different sizes. The size you order will depend on how worn your axle is. The shop that bores your axle should be able to help select the proper OD pins.

The spindles do not need any machining. Make sure your axle isn't already over-bored with std pins first..keep your fingers crossed.

Stuart

Stuart has covered just about everything. However, the worser-case scenario is not uncommon. If the king pins have been loose for a while (and they have, or the axle-bores would not be loose), then the bushings in the spindle bores might be wallowed-out. This problem is far more difficult to deal with (and, it is not uncommon).

However, if the pushings you installed were not loose in the spndles when you installed them (and they are still not loose when you take the kingpins out), then the spindle bores are most likely OK.

Keep your fingers crossed in hopes that the axle is the only problem and that a standard over-sized kingpin (readily available) will be tight in the rebored/reamed axle. Let us know what you find.

Thanks for the info. Would the oversize kingpins look different than the original. If only the axle needs boring wouldn't that make the kingpins odd-shaped with the original bushings? Wouldn't the kingpin have to be the same diameter from one end to the other. Just asking.

I am pretty sure with the 1 Ton setup, where the bushing are pressed in, that oversize kingpins requires reaming of the axle and the spindles.

truckernix is correct:

For Advance-Design trucks:
- 1/2 ton kingpin-bushings are "floating type", they do not have to be reamed and they do not need to be press-fit into the spindles.
- 3/4 ton and larger trucks have press-fit bushings that need to be reamed.

blkhrn,

The set of oversized kingpins (2 oversized pins) includes four bushings with oversized holes. Thus, the larger holes in the axle matches up with the larger diameter kingpins; and, the larger diameter kingpins fit in the larger holes inside the bushings. The bushings' outer diameters are the same as the originals'.

Tim

Is there something like bushings with oversized outer diameter for 1/2 ton?
I have kingpins fitting snug inside the axle, but I still got play on the spindles with a new kingpin set.

On the road again,

I am not sure! Even before the tapered pin is inserted into the axle, the pin fit should be "very very snug"...a hard hand press fit.

If your spindle bores are actually worn, they wouldn't be worn concentric, so would need to be re-bored in a precise manner. This would lead me to believe there are no standard OD-plus bushings in a over the counter set.

There are lots of combinations of king pin sets with press fit bushings, floating bushings, spiral bushings etc. If this is actually kingpins, and not wheel bearings, I think you would need to disassemble your spindle/axle and make sure what exactly you have.

Re-boring and bushing the spindles would be cake walk for a machine shop....there might also be sets that DO have oversize 'OD' bushings, who knows!

Stuart

Sounds like new or hardly used spindles are the way to go.

The previous owner(s) never did any repairs and the spindles are worn out by the bushings.
The kingpins fit very tightly into the axle and are not the problem - bearings are also perfectly tight.

I'm glad I read this post - I always thought oversized kingpins also come with oversized OD bushings...

Thanks as always for all the knowledgeable advice.

Are you sure the play is in the king pins & not the wheel brgs? It can trick you sometimes. Did the lock pins go in all the way? Sometimes the flats don,t line up. I drive a long tapered punch in before the lock pin. This gets the king pin in the right possition. If the looseness is in the bushing where it floats in the spindle & is minor amount I would leave it alone. I take it you greased them thouroly. You don,t need need an alignment shop. The only adjustment is the toe in. There was a post & discution about setting the toe a week or 2 ago on this websight.

You have gotten some VERY good advice!
The bushing play at the spindles can be "deceptive" due to machineing tolerances. Rule of thumb is if the bushing is dry it will "stick" when you put it in the spindle, but will "slide" when it is lightly lubricated. Also, I think the play SHOULD be minimized when the spindle/bushings are shot FULL of grease. Another factor I have noticed is that some places sell kingpins that are .861" in diameter which will cause slop in the axle bores. From the factory, the kingpins were .8660"-.8665"
However, if you do in fact have worn out spindles and/or axles,(or just do NOT like how they feel) any quality machine shop should be able to fix your problem; Here is a stovebolt link to how one guy did it:
http://www.stovebolt.com/techtips/spindlebushing.htm

Thanks again for all the good useful info. I think I found the problem to the play in the spindles. The top of the axle bore has somehow gotten wallowed out. The bottom of the bore is still tight with the kingpin inserted. The old pins were regular not oversized. The pin fits snug in the spindle bushings. Now, I just need to get it repaired. I appreciate the info that you all shared.