Kingpin Front Suspension - 1954 Pontiac
Original Kingpin suspension
Original suspension drawing except that the swaybar is mounted under the front frame rails not on top.
This is the passenger side spindle, upper control arm and lower control
Driver's side original steering - top is front of car
Passenger's side original steering (notice sway bar mounting at top of screen)
Rebuilding the Front Suspension
I was originally going to rebuild the front kingpin suspension. There's nothing wrong with kingpins except that you have to grease them routinely and there's 12 grease nipples per side! You can purchase complete rebuild kits from Kanter's which stocks tons of parts for older vehicles (pre 70s typically) or National Chevy Association which specializes in 49-54 Chevs. Another site for parts is Chevs of the 40s. What's really nice about these sites is the online catalogs. They have detailed pictures of the components!
Stainless Steel Brakes has what they call "Royal" kingpins which eliminates the old style brass bushings and replaces them with needle bearings. The primary kingpin is a heat treated shaft that requires no machining for installation. You use your existing uprights.
You can get dropped spindles from FatMan Fabricators There are several sources for 2" lowered uprights (the part that the spindle/kingpin assembly bolts to) and they are all about $450 Cdn. If you lower the front, you have to replace the steering arms with ones which compensate for the 2" difference otherwise you get bumpsteer!
You can get a front disk brake kit from Engineered Components Inc that uses mid 70s Camaro and Firebird rotors. I purchased one and had the chance to trial fit everything. It's a an easy and pretty slick install.
Who uses kingpins?
Corvettes used kingpin suspension til 1962 and Triumphs TR6s until 1976. I owned a 72 Triumph TR6 and it handled pretty damn good. So whoever says that kingpin suspension can't handle, think again! I think that it is the sloppy steering gear that is actually to blame and not the suspension. Replace the steering with a rack n pinion unit from out of a 1990 Cavalier or Sunbird and you can have a pretty nice ride!
Interestingly, modern Ford pick-ups, Rangers, vans and broncos use their split I-beam suspension which is basically a kingpin suspension design. Gives you food for thought doesn't it....