Everybody knows that when you buy a new set of tires one of the most important things you can do is to have the vehicle alignment checked. Suspension settles over the years, ball joints wear and tie rods can become bent or come out of adjustment. We've seen instances where a new set of tires has been damaged in as little as 100 miles because they were driven on after installing replacement suspension components but before checking vehicle alignment.
Indeed, the cost of an alignment is modest compared to the cost of tires, but there are other considerations involved. One of the most obvious ones is vehicle performance and safety. A bad alignment can leave you struggling to maintain lane control at freeway speeds, and a small amount of input results in the car lurching to one side or the other.
Sometimes a diagram can be...
Sometimes a diagram can be helpful to visualize the concepts we're talking about. This is the factory drawing for our '67 Fairlane Ranchero front suspension. It is taken from our 1967 Ford Shop Manual. To visualize adjustments, draw a vertical line in your mind between the two ball joints. To the extent that this line might deviate from vertical when viewed from the side is a caster adjustment. To the extent that it deviates from vertical when viewed from the front is a camber adjustment. The camber adjustment eccentric or cam is also shown in this diagram of our Ranchero suspension.
At the same time, an incorrect camber setting can leave you squealing through the most modest of turns. If your car shows any of these symptoms or if your vehicle alignment is an unknown quantity then checking your frontend for all the right specs is one of the best things you can do from both a vehicle safety and tire longevity standpoint. Another consideration is that a correctly aligned car is a pleasure to drive. Since the classic Ford vehicles we're interested in don't have four-wheel independent suspensions we won't discuss rear alignment except to say that similar considerations are involved.
If you've got several cars or are constantly changing alignment on a favorite because you alternate between street use and track use then the ability to check and adjust alignment at home or at the track can be a great asset. Fortunately, tools suitable for personal use are now available to check your classic Ford vehicle's alignment.
Front Of Car
This photo illustration shows the caster line as viewed from the side as well as the change possibilities for camber as viewed from the front of the vehicle. As shown, the camber is the deviation from vertical of the line drawn through the centerline of the tire tread face.
To begin our alignment lesson we ventured out to Marlo's Frame and Alignment in Canoga Park, California. There we were able to take advantage of Marlon's years of experience as he explained the ins and outs of front suspension alignment. Marlon doesn't have a laser-guided rack but rather uses old-school expertise and tools to align his customers' vehicles. As you will see, the tools he uses are similar to ones you can buy to attend to your alignment needs. After we go over an alignment procedure with him to get down the basics we'll also have a look at some of the vehicle-alignment tools available from the Eastwood Company.
There are three main aspects of vehicle frontend alignment. They include camber, caster and toe. Camber is the angle of the wheel, measured in degrees from exactly vertical, when viewed from the front of the vehicle. If the top of the wheel is leaning out from the center of the car, then the camber is positive. If it's leaning in then the camber is negative. If the camber is out of adjustment, it will cause tire wear on one side of the tire's tread. For example if the camber is excessively negative then the tire will wear on the inside of the tread.
When you turn the steering wheel, the front wheels turn on a spindle that is attached to the suspension at the upper and lower ball joints. Caster is the angle of this steering pivot, measured in degrees, when viewed from the side of the vehicle. If the top of the pivot is leaning toward the rear of the car, then the caster is positive, if it is leaning toward the front, it is negative. If the caster is out of adjustment, it will cause problems in straight line tracking. If the caster is different from side to side, the vehicle will pull to the side with the less positive caster. If the caster is equal but too negative, the steering will be light and the vehicle will wander and be difficult to keep in a straight line. If the caster is equal but too positive, the steering will be heavy and the steering wheel may kick back when you hit a bump.
Here the caster and camber...
Here the caster and camber gauge is affixed to the wheel. Using a bubble level on the tool, both caster and camber can be measured on a scale indicating degrees of deviation from zero. By observing the position of the bubble on the scale, Marlon is able to determine what adjustments need to be made. He'll take measurements with the wheel turned left and right, lock to lock.
On our Ranchero, the caster...
On our Ranchero, the caster is adjusted by shortening or lengthening the lower strut rod. Shortening the rod will bring the lower ball joint forward adding a little positive caster to achieve the setting desired. On earlier cars, such as '65-'66 Mustangs, the caster is adjusted by adding or subtracting shims from behind the upper control arm. Thus, on earlier cars the adjustment is achieved by moving the upper ball joint relative to the lower, instead of just the opposite.
With the wheels straight ahead,...
With the wheels straight ahead, Marlon checks the camber settings on the Ranchero. Our Ranchero was a little too knock kneed and we needed to remove a little excess negative camber. As the suspension wears or works its way out of adjustment it tends to add negative camber, taking the adjustment out of factory specs.