Recently, while at an alignment shop, I asked a technician if he could do alignments on old cars, explaining to him that they were cars of the 40s and 50s and were of king pin design. I told him I had all of the specifications and would have replaced and checked all of the front end components before I brought the car in. He told me that he could to it, but sometimes it might be necessary to heat and bend some of the steering components and that could be dangerous. Could be dangerous? That IS dangerous!
When I got back to my studio, I couldnt wait to go through the motors manuals. I wanted to be open minded, but the story I remember about re-heating heat-treated parts was about a Packard guy who wanted to remove the rear brake drum on a 48 Packard Custom 8. These drums are pressed on and have to be removed with a heavy duty 3-fingered puller. He didnt have one, so using a torch, he heated the drum and axle and beat on them with a hammer until the drum came off. Then after putting on new shoes, he took the Packard out for a test drive. You guessed itthe axle broke, the wheel came off, slamming him and the car against a retaining wall!
As I went through my manuals looking up alignment for king pin cars, alignment procedures were similar. Heres what I found. First, Id like to give a quick review of what a king pin alignment consists of. It assures that the wheels run true on properly adjusted bearings and that the steering system is properly lubricated. I am choosing information from a Chevy manual, since it is a good representation of most king pin systems.
KING PIN INCLINATION: The amount in degrees that the king pin tops are inclined toward the center of the vehicle. This helps to provide steering stability.
CASTER: The amount in degrees of the backward tilt from vertical of the king pin and knuckle support, also contributing to steering stability, similar to a bicycles front forks backward tilt that makes the bike self-steering.
CAMBER: The amount in degrees that the front wheels are tilted outward at the top from a vertical position. Tilting the wheel out at the top tends to make it run out from the vehicle. In other words, the left wheel pulls to the left and the right wheel pulls to the right. When a wheel is tilted out too far at the top, the result is wander and hard steering. Excessive wear on the outside will show on the tires. The car will pull in the direction of a wheel that is tilted more than the other. When wheels tilt in, tires wear on the inner shoulders.
TOE-IN: When the wheels are closer together in the front than at the rear. This is measured in fractions of an inch.
ADJUSTMENTS OF CASTER AND CAMBER are made by turning the upper control arm pivot pin.
The KING PIN support is held centrally on the pivot pin, which indexes with a groove in the pivot pin. This pivot pin is eccentric. This is evidenced by the movement resulting when the pin is turned. The factory recommended procedure for adjustment is to turn the pivot bolt until the travel of the bolt threads in the bushing gives an exact caster setting. Then turn the pivot bolt in the direction to reach the correct camber adjustment. The direction depends upon the eccentrics position (a tolerance of ½ degree is usually allowable).
King pin inclination and camber are interdependent. To change one changes the other. Chevrolet stated that front-system parts were exceptionally strong because of heat treating and that heating and chilling steering gear parts for alignment is a dangerous practice.
TO ADJUST TOE-IN: Loosen clamp bolts at each end of the left hand tie rod. By turning this tie rod, you can increase or decrease its length until you have the correct toe-in. Then the clamps are re-tightened.
This article is not intended to cover every aspect of front wheel alignment, but to strongly suggest that before you have any work done in or out of your shop, do your research! Read the basics of the project in motors manuals or google it on the internet. It might save your car, and maybe your life! Keep em driving!