King pin fit

Rich Bowes

Rich Bowes

Member
How should new king pins fit in the spindles. Should they be very tight, or should there be any play? should there be any clearance around the king pin, between the king pin and the spindle?
 
Guten Abend Rich. The fit is correct when the oiled components glide smoothly. This corresponds to approximately 5/100 mm clearance.
 
I ream both bushings together to .003-.004". Some specs will say .001" but I find them too tight to take grease.
 
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After pressing in new bushings new king pins will not fit until the bushings are reamed to .8125 inch. After reaming the pins should slide smoothly with no perceptable play. The actual clearance is probably less than .001 inch - like wrist pins. When reaming, a good practice is to press in a single new bushing and ream it using the old remaining bushing as a guide to ensure the bore is reamed concentrically, then press in the other bushing and ream again. When reassembling be sure to shim the assembly so the entire load is on the thrust bearing. Take your time and do the job right !
 
Best practice is at the machine shop and only if they have a Sunnen pinfiting machine or equivalent from Italy This will hone both bushings at the same time in alignment. Wheel cylinder hones can get out of round and no alignment. The special reamer, some alignment but no control over the final clearance.
 
Based on the price from Snyders I would think it would be cheaper to have a machine shop do it.

Why buy a $160 reamer if you are only going to use it once or twice.
 
How come in is not addressed in THE book : Model A Ford Service Bulletins Complete?
Didn't they ever change King Pins? HA! HA!
 
Have a Machine Shop do it.


I recently bought on eBay an old adjustable hone set specifically made for King Pins. It came with a whole box of new abrasives which will hone all the king pin bushings I will ever want to do and then a lot more. I paid about $35.00 and it really works well.


Before I found this, I always had my local machine shop hone the bushings.


Chris W.
 
Hello precision mechanic.

As a low-cost compromise, I rub the bush bearings with a hone stone brush (+/- $ 15.00) for hydraulic brake cylinders. They are very cheap. But they are sufficient for such simple requirements.
 
years ago I bought a king pin reamer from Bratton's that is long enough to ream both bushings in line. I have rebuilt six or seven front ends and used the reamer. I have never used a hone. I seem to have had good results with just using the reamer. The problem I had was trying to figure out what to do with all the bearing shims. I spoke with Les Andrews and he educated me about the geometry of the front end. The attached article is a para-phrase of Les Andrews conversation. The procedure has worked for me.

Tom Endy
 

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The best way I've found is to reem the bushes with a pilot on the reemer so they are in line. I stop while they are still a little too tight and use some valve lapping paste on the unworn part of the old king pin(the part that was in the axle) to bring them to a point where I can push the new king pin in with my finger. Clean the bush thoroughly before final assembly. If it is too tight, the car will be all over the road and you'll have to take it apart and do it properly (after you change your underwear!).
 
Rich Bowes said:
How should new king pins fit in the spindles. Should they be very tight, or should there be any play? should there be any clearance around the king pin, between the king pin and the spindle?
Click to expand...

Hello Rich:
The pin fit should just slide in: to quote a "Perfect fit"
Any machine shop that has a Sunnen hone can do them for you to achieve the perfect fit.
 

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  • king pin honing.jpg
    king pin honing.jpg
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I just brought my king pins to a shop that has a Sunnen. Mine slide in with a tiny bit of friction.

They charged $45 per side.
 
Was going to get mine honed until I stopped into A&L to pick up some parts and he gave me a nice piloted reamer to use. It worked great and the surface finish looks nice. Test fit of an NOS kingpin confirmed a nice tight fit.
 
old31 said:
I just brought my king pins to a shop that has a Sunnen. Mine slide in with a tiny bit of friction.

They charged $45 per side.
Click to expand...


$90 seems pricey for 2 spindles but then if they charge an hour of labor minimum I guess that makes sense.
 
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