The Stovebolt Site Forums The Parking Lot Big Bolts King Pin Bushings - What size reamer?

Hello bolters!

Got the king pin kit from Chevs of the 40s for my 1939 Chevy 1 1/2 ton fire truck. I know we could just take it to a machine shop, but I wanted us to ream out the new bushings ourselves. Anyone know what the exact right size is?

OR, do we just measure the new pins, and add a couple thousandths?

Thanks in advance,

-Michael

I believe the service manual is online at oldcarmanualproject.com. Should be in there. I have the 38 manual at home, and can take a look and see if its listed.

Hy Mikestem, I don't know the size, I just wanted to mention that the two bushings must be reamed inline with one another, either with the special two cutter long reamer shown in the maintenance manual, or with a reamer with a long extension on it which can be centered with a cone shaped adapter, hope that helps.

Hi
I have done this on my '47 1.5 ton. I had an adjustable reamer, and as 3B said above, an extension and a cone shaped adaptor that centred the extension dead centre of one end while I reamed the other end of the spindle.
From memory the clearance is .002" and I set mine to about .0015", scared if I tried to get it closer I would go over.
Kingpin size was .921"??

I set up the spindle in a vice and used a dial guage to check the clearance. I inserted the kingpin, and held it against one side, top and bottom, and zeroed the dial guage. Then I would move the whole kingpin over to the other side and hold it there tight, and the dial guage would tell me how much play there was in the spindle.
It was exacting work but it did come out perfect. I had to carefully ream each end out to just big enough, and take both ends out in stages, oneafter the other, for the measurement to be accurate. It was slow work.
I got my kingpins off Truckandcarshop. No problem overall but one of the kingpins had a .003" taper over the last half inch, this is incorrect, and it would seize in the spindle when I inserted it and did a bit of damage. I was able to lathe it correct. Watch for that although I bet its rare.

If you use an adjustable reamer, disassemble it first and clean it perfectly so theres no swarf in the channels. Work out what the change in size per turn is, and be conservative when adjusting. you only get one chance to get it right.
On the plus side, mine are perfect, and I am a beginner- so it can be done.
Good luck.

Reaming them both inline is the goal, a piloted reamer lets you do it. I ream them just large enough to slip the king pin in with a push of your thumb.

Grigg

Thanks, you guys - you have, as usual, educated me, and given me greater confidence.

My mechanic and I surfed for a suitable piloted reamer. The only one we found we were comfortable with was $155.00 at McMaster Carr, and it didn't seem worth it for something we may never need again.

Dropped the kingpins, bushings, and steering knuckles at a local machine shop I'm confident of. May live to regret not doing it in-house, but life is risk!

Will have them back Thursday - will advise about the quality and cost!

Thanks, all!

-Michael

As a follow up:

Picked up the machined bushings today. Dropped them off Tuesday late afternoon, was called Wednesday at 10:30 and told they were ready. $80.00. I would have been happy with anything below $100. Well worth it.

-Michael