The Stovebolt Site Forums The Shop Area Driveline Kingpin Problem

Well, I was doing fine and then everything got screwed up. I am rebuilding a 1956 3600. I pressed the old kingpings out and drove the old bushings out of the spindles. I then drove the new bushings into the spindles. Heavily greased the thrust bearings and spindle bores and placed the new kingpins in the freezer for a few days to make them easier to press into the spindle bores. I went to drive them in with a drift and 3 lb sledge and after a few good whacks I could tell something was wrong. The new kingpin didn't press into the spindle bearing at all but instead destroyed the upper spindle bearing. Skewing it to one side and gauging the hell out of the bearing surface. It is now ruined. I stopped at the one side. Now I guess I have to order an entire new kingpin set just for one bearing and am stumped on how to drive in the new kingpins without destroying the bearings. Any and all suggestions welcome. How do you do this?

Dd you follow the procedure in your 1956 Shop Manual?

The 1955-2nd series Shop Manual procedure should be similar to 1956. Did you ream the new bushings?

I followed the procedure except for the reaming. I have read conflicting reviews about if the new bushings need reaming and I measured the new kingpins with a caliper and they don't appear to be tapered.


I am now thinking that is the problem and the spindle bushings need to be reamed first. What is the spec on the reamer that I need? The shop manual says 0.923" reamer but I have never seen a reamer like that before that will pass through both bushings.

Can you elaborate please?

Put the new bushings in the spindle. They then need to be line reamed so the pin can be pushed through with light pressure. If you don't have a reamer you can take them to a machine shop & have them fitted. This is on your 3/4 ton. Some 1/2 ton trucks have floating bushings & don't need to be reamed.

I just ordered parts today and saw no 1/2 tons sporting anything but floating bushings... and boy was I ever glad I didn't have to buy a reamer! that would of been a trip to the shop for me. I think I got all my king pins and spring pins and bushings for the price of a reamer from the google search... and the there's the ebay link.

1947-59 1/2 ton GM trucks' king pin bushing are floating - no reaming the bushings.

Larger 47-59 GM trucks king pin bushings need to be reamed.

This applies to standard and over-sized bushings.

Of course, if you have to use an over-sized king pin because the king pin is loose in the axle, you will have to drill/ream the holes in the axle to fit the larger diameter of an over-sized king pin (for all sizes of trucks).

Thanks everyone!

I got it all put back together last night. Picked up a new bushing set and an adjustable reamer from grainger.
http://www.grainger.com/Grainger/WESTWARD-Adjustable-Hand-Reamer-4LGT4?Pid=search

Then went to town reaming with some cutting fluid. My kingpings measured 0.9215 so I bored out the spindle bushings to 0.001 interference or a 0.9225 ID. It took about 30-40 min per spindle but it is done and seems to fit very nicely. FYI the bearing ID measured 0.8995 before which was quite a bit of material to remove.

I installed the spindles with thrust washers and shims and everything is very smooth and easy to steer. It was very stiff before with spots were it was binding.