The Stovebolt Site Forums The Parking Lot Tons 'o Fun Replacing Kingpins

I am trying to replace my king pins on my 49 3800. In all of the looking around for parts I found that there are two sizes of kingpins to put back in. I ordered the regular size pins and when I got them I was eyeballing everything to see if it felt right and the bushings appeared to be correctly sized but when I tried slipping the pin in the axle it had a little bit of play between the pin and the hole in the axle. Pulling out a caliper it looked like my old pins were about .922 and the new ones were about .917. I decided that I probably needed the over-sized kingpins. I sent the regular sized back and found the over-sized at Classic Industries. When they arrived I tried the pins in the whole and there appeared to be even more clearance. The bushing are about double the thickness but the pins are smaller. Can it be that I actually need the regular size pins and that the .005 that they appeared to be off is within the tolerances? How much play is allowed/expected between the pin and the axle? The shop manual made it sound like they should be snug.

pin and axle should be quite snug, no tighter than tap it in with only a whack or two with a rubber mallet snug, definitely not slide on through with their own weight.

The bushings will need to be installed in the spindles and then reamed to fit the king pins, light press fit with your hand.

If the largest available oversize kingpin (only one oversize option?) is a loose fit in your axle you should look for a better axle beam. If the oversize pin won't fit you can ream the axle beam to fit the pin, that's standard practice when correcting a worn original to use oversize pins.

There is standard size & .010 oversize. When you use the oversize the axle has to be reamed or honed out. There should be an interference fit where it goes in the axle. I don't understand your situation. Maybe you are already 10 over & the second set is not right. The manual is right. They need to be snug.

Rockauto sells over-size kingpins in two sizes; .010 and .020 over-size (in two brands: AC-Delco and Raybestos)

http://www.rockauto.com/catalog/raframecatalog.php?carcode=1486934&parttype=7340

I had my King Pins re-done on my at-the-time 1946 One Ton Pick Up, back in 1979.

Anyway, the place I took it to was a bunch of old skinny chain-smoking guys who had been doing front end stuff since the 1940s.

They took the Axel ends apart, heated the King Pin 'Eye' ends to a good Cherry 'red', Dollied them 'in' all round, then once cool, reemed the Holes, and put the new King Pins in.

Turned out perfect!

I put over 400,000 miles on them afteward and they were still excellent and snug ( I always Lubed every 2,000 miles or sooner ).

Initially mine were wallowed pretty bad and past what the available 'oversize' would correct.

Plus, when wallowed, they are no longer 'round' inside and will need to be at least reemed, and to have over-over-size pins ( which one can make or have made if need be )...or, one heats and Dollies it all in and then reems for standard or as one pleases.

Thank you tclederman. I've ordered what should be the correct ones from rock auto and can't wait until they get here.

old49joe,

Please let us know how this ends up.

Thanks,

Ordered another set of pins from Rock Auto but embarrassingly enough I ordered the wrong set again. It turns out that my digital caliper needed one more decimal place of precision. I've taken it into a local machine shop to have them take care of it for me now.

Machine shop got it all sorted out. The truck did have oversize pins and apparently I was shipped a pair of regular size pins when I ordered oversized. The new pins fit perfectly and there is no play at all.