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King pins

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Happy New Year!


My 1930 Dodge Brothers DC has a bit of vertical movement in the left steering knuckle. It appears the thrust bearing is collapsing. I expect I can buy a thrust bearing here in New Zealand, but not sure about the king pin. So I have two questions - maybe I can get something by size rather than application. I want to have the parts in hand or at least sources lined up before I dismantle. I am hoping someone will have a set on the shelf...


1. What size is the king pin - diameter and length and where is the locking pin groove?


2. What are king pins made of? If necessary I should be able to turn one up out of suitable steel.


The king pins (part no. 42656) and the bushes, bearing, expansion plugs, shims and lock pin were also used in the following:


Dodge Brothers  DD, DE, DF, DH, DC, DJ, DG, DL, DM;

Plymouth  '28 Q, 29-U, 30-U, PA, PB (thanks to ply33.com for that);

De Soto  6 and 8, '29, '30, '31;

Chrysler  66 ('30-'31), 1931 six.


Oh, a 3rd question. What are the bushes? Oilite or brass with a hole in them to let the grease in?


Thanks for your help.

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   I have a 1936 King Prod Co catalog that lists your set;  King Pin (aka steering knuckle bolt) their then #K963 lists as .749 OD, 61/4 in length under head...King Prod is long gone; someone here noted who took them over but i failed to note it...HOWEVER, a 1941 McQuay-Norris catalog USES EXACTLY THE SAME NUMBERS which your parts houses may be able to cross index...

   FWIW, my catalog lists what appears to be a wider? set of vehicles using this set:

    Chry--28-33---models 52 (4 cyl with 4 wheel brakes), 66, CJ, CM, CI, CO 6s;

    DeSoto---28-33---K, CK, SA, SC, SD 6s, CF 8;

    Dodge---30-32---DM 4cyk, DD, DF, DH, DL 6s, DC DG 8s (no DE, DJ),

    Dodge Trk---30-32---Merchants Express, UF10 4cyl, F10 6cyl 1/2Ton;

    Plym---28-32---Q, U, 30U, PA, PB.

   King Bolt Assembly kit # KA4 (both catalogs) includes

    2 K963 king bolts

    2 KB9433 upper bushings

    2 KB9633  lower bushings

    2 K1075 lock pins

    3 T963 steering arm and tie rod ball

    4 M42 expansion plugs

    4 M71 shims

    2 unidentified thrust bearings in the 36 catalog, listed as M41 thrust bearings in the 41 catalog

   I have no info re' your other questions...Bud..



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There is a set on E-bay--listed for the 31 Plymouth PA ---not very cheap ---but they have it listed ---Allan

Wow, I can make them far cheaper than that! And they call them selves Car Parts Discount! Huh!


It looks like the locking pins are parallel sided. Does it matter which way I knock them out - to front or back?

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Wow, I can make them far cheaper than that! And they call them selves Car Parts Discount! Huh!


It looks like the locking pins are parallel sided. Does it matter which way I knock them out - to front or back?

I believe those pins are tapered if I remember correctly when I rebuilt mine in my '31 DB. Look very closely at each side of the pin. One side should be smaller.

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OK, I have taken it apart. There was a surprise!


I pushed the pin out with this rig:



Pin removes to rear, the right in the photo. A few copper faced hammer taps on the pin on the left, once tightened, released the pin. This is an el-cheapo bearing puller set.


The king pin came out easily, downwards. It is in reasonable re-usable condition and is 0.749" dia. and 6.25" long, as Bud stated above. The thrust bearing was the surprise. I have not seen one like this before




A pin in the axle yoke locks in the top of the bearing and a ridge on the steering knuckle locks in the slot on the bottom.


The Plymouth PA and PB set listed on ebay do not have the locating holes, nor do any others I can see on ebay. Two part numbers are listed, one for export and one for domestic. I wonder if this is the export version?


I assume I can just remove the pin and ridge on the axle and knuckle and use an ordinary thrust bearing?


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Spinneyhill your king pins appear to be very similar to my 29 Chrysler.Very complicated way to remove the cotter pin , normally a hammer and punch will shift them.My thrust bearings are the same, they cleaned up and feel good so will be re used, I bought bronze bushes from the local bearing suppliers, drilled the hole and used the die grinder to make a small spiral groove for the grease. Intending to make my own king pins, can source some 7/8 chromed medium tensile shaft, but not sure if this is suitable, what do you think?

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I tried the club hammer and punch on the pin with no success. I didn't want to keep hammering it because once the pin was belled it would be harder to get out.


Like you I would make my own king pins if I had to. I haven't looked at the steel to use but the one you mention sounds suitable. Just polishing suitable 0.75" steel would be fine for me. Timken T76 will work for the thrust bearing although it will need thick shims.


I shall be buying bushes as you have but I was not planning on putting in grease grooves. I have read they just provide a channel for the grease to get to the outside without being forced around the area to be lubricated. T76 is 0.760" ID so there is space for grease to get inside it.


I could probably use the old bearing at a pinch but it is pretty sloppy. It runs smoothly as far as my non-expert hands can tell but is clearly very worn. There is a gap around the bottom of the shroud where dirt can get in. There was a floating piece of metal on the bearing when removed - I suppose it was the remnant of a shim, the rest having broken up and fallen out. I could push 25 thou in before dismantling.

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I asked a machinist forum what steel to use for king pins. The thread is at



It looks like the hardness is important as well as the strength. 4140HT is 28-32RC, a lot less than the last couple of posts talk about. I wonder if 34 FORDOR's suggested steel is strong and hard enough. The chrome might strip off in shear so probably not a good idea.

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I bought a metre of 5/8" (or was it 16 mm?) silver steel from Bay Engineer's Supplies in Tauranga, for my water pump shaft. But I don't know the properties of it, except it is pretty much tool steel and can be hardened to make cutters etc.. I will find out what it is. Otherwise, currently I have two avenues of approach. My engineering mentor (used to own a machine shop) and a machine shop -  they may recognise the type of steel and may have suitable offcuts or bar in stock.

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The supplier of the silver steel I bought was probably Milsons in Palmerston North. They are wholesalers, not retailers. They sent me the properties sheet for it, however.


Silver steel is often known as drill rod in the US, or tool steel, but is probably not the same (American drill rod will be made to a different standard). SS is made to BS1407 and supplied in ground finish rod in 1 m lengths. 3/4" is available. I didn't ask about 7/8". They deal with most steel suppliers, Steel and Tube, Steelmaster etc.. Just ask your local favourite supplier.


Here is the spec sheet. They supply 61 HRC steel, which means a tempering temperature of about 200 °C. Now I have the spec's, I'll ask the machinist forum what they think. Typical uses include axles, tools, cutters and so on.



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Visited my engineering mentor today. I will use a new bearing, make up a shim for it (0.109-0.110" thick) and grind off the pins. I may put in new bushes. I'll look again at them and the play. The king pin will be re-used. He pointed out the X shape on the king pin inside the top bush: rust marks. So water had been in there and not enough grease. The top expansion plug (commonly known as frost plugs in the shops, or core plugs) was there but just sitting there. The bottom plug was gone. Installing them should make a huge difference to the ability to keep grease in the bushes. I'll make the shim on the lathe from a piece of 38 mm rod.


As far as the silver steel goes, it would need further hardening after grinding the locking pin groove.

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34 FORDOR, the home machinist forum tells me silver steel is not suitable. The latest recommendation is something like AISI/SAE 8620 which is suitable for case hardening. Atlas call their version Impacto, but 8620 is a more common designation. This job probably needs to be professionally case hardened.


The process seems to be that given by "hermetic" at post #7 on my thread:



So it is not as simple as I naively and ignorantly assumed.

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