The Stovebolt Site Forums The Parking Lot Tons 'o Fun KINGPIN REAMING

my question has to do with the process of reaming the new kingpin bushings in my 1 ton gmc.it seems that by the time i remove enough material for the kingpin to fit in the bushings i have removed almost all of the bronze sleave from the steel outer shell is this normal???????

Hy amabolter, welcome, kingpin reaming is done with a special reamer setup so that you are reaming straight through both bushing bores. If you don't ream both bores inline then you have to ream at least one oversize so that the pin will go through. If you are reaming them properly, then as long as you have some bearing material left, and hopefully some grease channel, you should be good to go, hope that helps.

thanks for your reply,I have one side done with a brake cylinder hone.It fits well with a firm thumb push and no play up or down.It just concerned me that so mucn material had to be removed.I read in my service manual that the 1/2 ton trucks use a bushing that is machined to finish size,no reaming required.Is the system used on the larger trucks better,stronger? Or are us larger truck owners just being discriminated against????

The larger truck method of reaming after installing is better, even though it is more work.

If you want them to last it is important that they both be on size and have the same centerline when done.

To accomplish this there are piloted reamers.
Or supposedly better yet is to have them professionally honed to size (and parallel) at an auto machine shop. They say honed king pin bushings last longer than reamed.

You can ream or hone one without referencing the other, and the pin may "fit" but the results may not be desirable, they may not last long.
Ideally you ream/hone one bushing with reference to the other bushing.

Grigg

Thank you for your reply,I agree that line boring both kingpins inline is prefered in a perfect world.It took me a few hours of carefull honing to get a good fit.What a pain in the #ss but well worth the bill at the machine shop I would have paid.That money will be spent on the many little things that pop up when restoring a 60 plus year old truck.Besides the real fun is doing it yourself when you can.It is alot more entertaining than watching Television exept for the recent election results.Man that was almost as good as when I got the engine running in my truck before I tore it down.

Last time I had kingpins honed at the machine shop it was quite cheap. I forget the exact price, but it was certainly a "no brainer" decision. And I have my own general machine shop, even have plenty of adjustable reamers, some with pilots, and like to do all I can myself. But when someone else can do a better job faster for little money I'll go for the better results.

Did you check the price at a few of your local automotive machine shops?

Grigg

Grigg,

What would you say to $400 for reaming a 1/2 ton axle for over-sized kingpins? That is what my local NAPA machine shop quoted. I bought a real nice adjustable reamer for less than $50 (delivered - eBay). I was very slow and careful - took me about 1 hour to do both sides.

I'd say you need to find a new machine shop.
Wow that's a lot of money, for what you know is reasonably simple!

Even to carefully set up the axle in the mill and accurately bore the hole larger taking the kingpin inclination angle into account shouldn't take that much time/money.
Must have been a job they didn't want to do, and instead of telling you as much they give an exaggerated price, possibly now keeping you from coming back later...?

Grigg

Same price at a big truck repair shop in the area.

I agree - they were telling me that they both did not want to do it (I had figured $75-$150).

Hello fellow bolters as a newbie to antique truck restoration I hope I did not offend any one with my questions or replies.I seem to have opened up a can of worms as to the choices of doing a simple but time consuming job of fitting kingpins into the bushings.My origional question was if it normal to have to remove soo much material from a brand new bushing?I just thought a new bushing should be machined to fit the new kingpin that came in the same box.I guess when we are dealing with vehicles that were built 60 plus years ago some fine tuning is to be expected.Getting ready for the sandblaster coming over to do frame tomorrow ,can,t wait to get frame done because now I can start putting parts back on!!!!!

Don't think anyone is offended?

Back to the original question,
"Is it normal to have to remove so much material from a brand new bushing?"

How much exactly is "so much"?
What was the ID before you started and what is the pin size?

But as mentioned earlier basically if you still have well defined grease groves on the inside of the bushings then all is well, you removed what you had to to get the pin to fit, and the bushings were likely the right ones.

Again, it is normal practice to ream kingpin bushings after they have been installed, just as your service manual said you'd have to do (except for 1/2 ton).
This allows for any small inaccuracies in the spindle bores and their alignment to be of little consequence because the bushings are then reamed together with the same centerline, for a snug and long lasting fit ion the pin.

The point we were trying to make is that if you ream or hone the bushings individually you very likely miss out on the whole design and plan of ream in place king pin bushings.

Grigg

I understand and thanks for all your help.The front end is all assembled and ready to install on frame.Absolutly no play up or down and nice and smooth turning left to right,all new tie rods drag link,etc.My sandblaster came by yesterday and did frame.My homemade rotiserie worked out well and made spraying the POR-15 a breeze.The frame looks like it was powdercoated i,m very impressed with the product will see if it holds up to their claims. Thanks again for everyones help and support this website is great I will try to post more pix soon. p.s.Ihave yet to figure out how to post pix on this site but have some on old gmc trucks.com

The half ton trucks use a "floating" bushing which I think is inferior. The bushings themselves can move around and I think it is common to end up with wear in the spindle itself.

While on the subject of kingpins I have a question on a '51 1/2 ton spindle it appears the bushing stuck on the kingpin and wore the spindle bore slightly. I have noticed there are .010 over kits are available. What is oversized in these kits the OD of the bushings or the OD of the king pin ? What is the allowable
"looseness" of the bushing to spindle bore ? I thought about
using Locktite RC640 or similar product to bond the bushings to the spindle bore with pins installed for alignment. Any thoughts or advise appreciated.

Oversize king pin kits are usually or always the pin diameter, not bushing OD.

If not to sloppy using loctite bearing retaining compound on the bushing OD sounds like a great idea to me, and for sure have the pins installed for alignment during setup.
I've done it once, and it seems to work out well.
I think the factory plan for the 1/2 ton busings to be completely floating, and therefore wearing the spindle bores is a really lousy idea. By fixing the bushings in the bores you're left with the exact same setup the larger trucks use, and no more wear in the bores in the spindle.

Grigg