Kingpin diameters

[FORDification]

Have a question for those of you who have a bit more experience with this area than me: Are the kingpins all the same diameter during all the Twin I-Beam suspension years ('65-'79)? I was under the impression that they were all the same diameter, but I've recently been told that sometime in the mid-'70s the diameter changed.

I was at the parts store today and had them look the parts up in their book and was told that there were two different part numbers, one used for '68-'74 and another used for '75-'79. Of course, the book doesn't say WHY the numbers are different, so that really doesn't tell me much. Also, are there any differences in kingpin diameter and/or design between the 1/2, 3/4, and 1-ton trucks?

Once I find this out for sure one way or the other, I'll be posting this info on the website for future reference.

[dotcentral]

I thought I'd read somewhere that there was one diameter for 1/2 tons and lower GWR 3/4 tons, and a larger diameter for heavier 3/4 and 1 tons. Might be getting that confused with something else though.

[Tim P.]

Keith have you learned any more info on kingpin dia. my parts store stated that there are two styles one with nylon type the other brass and they must be honed to fit kingpin dia, Im really confused about this as i have been discourage in venturing in to this project, one garage quoted 600.00 to do the job, it looks easier in theory

[FORDification]

Yes, I spent an evening doing research into that, and posted what I found on the DISC BRAKE TUTORIAL. Take a look there....but basically, there are three different kingpins with different diameters and lengths. Each can be gotten with either nylon or brass bushings. Nylon goes in a lot easier (don't have to be pressed or reamed) but wear out a lot faster. I'd highly suggest going with the brass, so that you'll virtually never have to worry about them again.

Replacing the kingpins yourself isn't that big a deal. You can drop your front end in about 30-45 minutes, disassemble it most of the way in about another hour....down to the bare I-beam/spindle combo. However, just to make it easier, I think I would suggest then dropping off the I-beam/spindle assembly at the local machine shop and having them press the kingpins out, the new brass bushings in and reamed, and the new kingpins installed. The kingpin set (enough for both sides) will run you about $50, and you're looking at another $75-100 to have the machine shop do the removal and reinstallation of the kingpins and bushings. Then another afternoon's worth of work putting everything back together into the truck. Piece of cake...relatively speaking, of course. And that's assuming you have a good set of tools.

[Tim P.]

Ok Keith I didnt think to look in the disc section as i dont have them on my truck and not ready to look at that at this time as far as a change over is concerened and yes a good set of tools are essential in front supension work all ready had the replaced the coils and radius bushings ,,,,that was a piece of cake so the rest will be easy and yes i would take to a shop for the pin fitting stuff there better suited for that type of work as you suggested. Thank You For reply. Tim P. Oh PS Im lookin to buy a good block from Vern here shortly,, Thank You again.

[oldschoolrods]

Keith, I did them myself on my 69, some 69's came with nylon bushings, so you don't have to have them reamed, you can drive the kingpins right out.

[michaelbrainard]

I replaced the king pins on my 69 - which had nylon bushings so that is what they were replaced with...it was a southern truck so it came apart nicely.

As far as diameter I know for my 1977 there are different diameters and lengths. The single piston disk brake king pin is around .85"...the dual piston is closer ( or over ) one inch. Go to www.partsamerica.com and do a search, by vehicle and it will give you several options. I was there last night. Turns out my truck has the dual piston front disk brakes, so I guess I need the larger king pins...