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King Pin Bearing Material for '22 Paterson?


Guest Paterson Chris

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Guest Paterson Chris

Hello All --

The above barn find has excessive slop in the driver's side king pin bushings. The king pin itself, no wear of note.

My question: what sort of material should I replace the old king pin bushings with? I searched previous posts and can't find anything. I was surprised to see that the old ones are made of steel (I double-checked with a magnet). I thought they would be bronze or brass? In looking through my McMaster-Carr catalog, I see that I have a multitude of choices. There's oil impregnated bronze, graphite impregnated bronze, cored bronze rounds, along with brass, steel, etc. By the way, lubrication points are via flip top oilers and an oil can so this won't be greased. What's the most durable that will make for the least amount of wear on the king pin? Finally, in these parts -- high Sierra Nevada -- paved roads are rare, so that's why I'm giving this some extra attention.

Thanks.

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I have four cars with steel kingpin bushes. 1911 Lancia Delta has bushes that are not hardened, even though one is compound, part of it being also one side of the vertical thrust ball bearing. (This is badly Brinelled, of course). 1923 6 cyl 6 litre cuff-valve Peugeot is similar, and will also have to be remade. Two Roamers, 6 and 4 cylinder have Stanpar axles with hardened bushings as well as hardened pins, and they aare in good condition.

I guess I have become more particular as I have gathered more capability in my workshop. And I decide between replacement, use, and compromise with a micrometer. Best reference which you could trace if Antique Automobile has a complete index now is a restoration guide by Tom Reese about 25 years ago, based on Inspection, Repair Or Replace As Necessary. Hypothetically, if I had a similar situation (and I had a lathe but no ability to grind), I might make new steel bushes, then build up any wear on kingpins with nickel bronze ( by oxy torch), and finish to size on the lathe. The nickel bronze is work-hardening. You generally find that disimilar metals in contact give better sevice. Ivan Saxton

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Guest Paterson Chris

Okay, I do have a lathe (two, actually) and appreciate your comments on remaining with steel, but in spite of that, am still set on using bronze replacements. The old ones will be saved for posterity. I just want someone to tell me what sort of SAE hardness grade I should ideally go with. Or will the hardware store oil-impregnated (also known as sintered bronze?) ones be enough to last me the next few years? It only takes me an hour to change them out start to finish, but I don't want to replace them with something so soft that I'm replacing them every six months either.

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McMaster-Carr lists about a dozen bronze alloys. It calls #936 the premier bearing alloy. Personally I would not use sintered bronze due to it's "spongyness" under shock loads. They sell the alloys in solid and cored rods.....Bob

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Chris, I would pick one and go with it. Remember, all right, write down which one you used and see how long they last. I've made a few soft drill rod king pins and bronze bushings for diferant projects. With the few miles and type of driving I doubt you will have any problem with whatever you choose. Keep them lubriacted. I've found the steel pins usually wear faster then the bronze bushings, VW used king pins until '65. I do agree with not useing sintered bronze because of the shock may break them. McMaster-Carr would be my first choice. Just an opinion.

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Guest Paterson Chris

Thanks guys for your input so far. I ended up ordering alloy type #932 bronze bushings (SAE #660), received them today, fitted and carefully reamed them to fit. Beautiful. Enough to bring a tear to my eye. HOWEVER, holy shukin' fit batman, what's THIS?!? The top of the spindle bore that the kingpin resides in is sorta, well, oval shaped. Not good. It's roughly as much as 0.040" out of round. So that's why the wheel was so wobbly....

A new question for y'all then:

Will carefully drilling the spindle kingpin hole from the good side (bottom) the next size larger (13/16", up from the stock 3/4") then fitting it with a sleeve made on my lathe be an acceptable fix? By me drilling it a sixteenth of an inch larger I'm not too critically weakening things am I?

Thanks again!

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Guest Paterson Chris

Sorry, by me referring to spindle kingpin bore I'm really referring to the steering knuckle kingpin bore. I rarely work on this part of a car so I sometimes get my terminology cofused.

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Guest Paterson Chris

Thanks, I'll do that. I've resigned myself to cobbling up some sort of sleeve to fix the hole. The most difficult part will be in first drilling the bore hole oversize as it's such an odd shaped part to secure on the drill press table.

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There is another way you can tackle this out-of round, which I learned from Arthur Lang and have used a number of times since when there has been little other alternative. The 180 Inter truck which Arthur bought for $10 without an engine,( and built up to use for the first time for a trip to outback Queensland in 1968), had loose kingpin eyes in the front axle. That occasion they were loose, but not oval, so he heated the inside of the holes with the big oxy torch end, while an assistant kept the outside quenched with water replenishment on a wet rag. WHen a hole is oval, I turn up a piece of shaft to the exact size the hole should be, then heat the outside of the eye to plastic state, then tap the material in onto the mandrel. When it cools, it shrinks down tight and round. If it has streched out of round, it probably means it was soft in the first place. Pretty much any bearing bronze is fine, but if you want to look up materials it is good to get a copy of Machinery's Handbook. Some of the older ones may be more interesting, and you should have little trouble getting what you want from abebooks.

Regards, Ivan Saxton

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I think I would go the sleeve route. I think that careful alignment and a boring bar head on a vertical mill (Bridgeport) would be the best and safest way to go. That would be accurate enough that you could then go for a good press or even shrink fit with the bushing. Plus you would not have to worry about a heavy duty clamp set up as the tool loads would be very light. Just my 2 cents worth, several ways to skin this cat....Bob

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You are right Bob, that there are many ways. I have personally never liked the separate sleeve option because it takes away material. Two other options are to use a steel/epoxy like Devcon to fill the gap. I have seen this done on heavy earthmoving gear with complete success. (I have Metco metal spray equipment and materials so I always use this on larger jobs.) The other thing you can do is make up a bush larger in OD and smaller in ID. Mark where you need to take off material around the circumference to bring it back to the original bore size where it is not worn. You make the bush slightly over-length so you can turn an index of the correct diameter on both ends. Then with a good file you cut to the same profile as the worn hole. Naturally it should be too tight to go in. If you take a thermos to the nearest medico you should be able to get some of the liquid nitrogen they use to freeze off skin spots. (You can alternatively use dry ice and alcohol, which mixture is not as cold, --minus 70degrees centigrade from memory). High school physics, the coefficient of linear expansion, is very useful. Then you ream for fit.

To quote what Henry Leland famously said to the English who were amazed that he could make single cylinder Cadillacs with interchangeable parts and spare parts: --- "you have to decide what you want to do and how you are going to do it; then you do it the way you decided". You have a few alternatives, Chris; and only you will be able to know which is the most suitable. Good luck with it, and have fun driving the car; because that is the most important part.

Regards, Ivan

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Guest Paterson Chris

Thanks gentlemen for your input. I decided to go with the sleeve route. I lopped off a length of common 1/2" galvanized pipe, chucked it up in the lathe, and roughly turned it down to size and drilled out the inside to almost fit the kingpin. At the same time using a set of adjustable reamers (there's almost no reason not to have a set -- the stuff coming out of China and India is so cheap even if only used a few times) and using the bottom of the steering knuckle as my entrance point and guide (since that had the least wear), I then reamed out the bore of the steering knuckle until it was perfectly round again. I then went back and turned down the outside of the sleeve until it was about 0.001-0.002" larger than the bore it goes into. I was able to then press it in using a length of threaded rod, nuts, and washers. I then chased the inside of the sleeve with a reamer and fitted the kingpin for fit. Still a little tight -- which is good -- but as I want to be able to easily remove it for maintenance on occasion, then finished up by honing the inside of the sleeve with a small brake hone and some valve grinding compound. Nice. Finally, there's a drift pin hole that secures the kingpin in the knuckle so I filed the inside of that hole (because it was now partially obstructed by the new sleeve) and finished by chasing the hole with a drill bit and cleaning the hole of any burrs. I finished by mounting it back on to the car, lubricating certain points, mounting the wheel, etc. -- all basically a non-event. All done! Yay! I'll end by writing that the walls of my sleeve are only 1/32" larger than the original bore so I feel that by removing so little metal I haven't compomised the structural integrity of the overall part in any significant way. Patience was key with this. I had about 20 hours and $30 in expenses into it. God knows what it would cost me to have a mechanic/ machine shop do the work. Having an older bench top South Bend lathe pays for itself with just this job alone.

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