How to Adjust the Caster on a '65 Mustang

The front suspension used on a 1965 Mustang has an adjustable caster, a term used in front-wheel alignment that refers to the forward or rearward tilt of the upper front suspension ball joint in relation to the lower ball joint. The caster must be set to the proper degree to attain the safest level of handling and to maximize the cornering capability of the car. Negative caster is attained when the upper ball joint is closer to the front of the car than the lower ball joint. Positive caster is when the upper ball joint is closer to the rear of the car than the lower ball joint.

Instructions

1

Attach a caster/camber gauge to the drivers side front wheel, using the directions that came with the tool. Continue to follow the directions to determine what the caster angle is. Note that the desired degree of angle on V-8-powered 1965 Mustangs is zero, but a tolerance of one degree in either direction is acceptable. Note that the desired angle on six-cylinder-powered Mustangs is one degree of positive caster, with a tolerance of one degree in either direction.

2

Slide under the front of the car and spray the two large retaining bolts that attach the upper control arm to the front frame rail with penetrating fluid. Allow the fluid to soak in for several minutes. Allow the fluid to soak in overnight, if the bolts are badly rusted.

3

Loosen the bolts a few turns with a socket and breaker bar, but only far enough that shims can be added or removed from in between the control arm and the frame rail. Do not completely remove the bolts.

4

Remove shims from in between the control arm and the frame rail at the front bolt or remove shims from the rear bolt, if the caster-camber gauge indicated that there is too much positive caster, as either of these actions will move the upper ball joint forward in relation to the lower ball joint. Place the tip of a large pry bar in between the upper control arm and the frame rail to lever the arm out enough to add or remove shims as necessary. Do not allow your fingers to get into the pinch-point between the control arm and the frame rail. Note that adding or removing a shim that is 1/32-inch thick will change the caster -degree. For instance, if the caster/camber gauge indicated 1 -degrees of positive caster, removing one shim from the front bolt or adding a shim to the rear bolt will create one degree of positive caster.

5

Remove shims from in between the control arm and the frame rail at the rear control arm bolt or add shims from the front bolt if the caster-camber gauge indicated that there is too much negative caster, as either of these actions will move the upper ball joint rearward in relation to the lower ball joint. Note that adding or removing a 1/32-inch thick shim will change the caster by -degree.

6

Tighten the upper control arm bolts after shims have been added or removed with the socket and pry bar. Check the caster angle on the gauge. Loosen the bolts to fine-tune the caster angle further by adding or removing shims. Tighten the bolts to between 55 and 65 foot-pounds with a socket and torque wrench after all adjustments are complete.

7

Check and adjust the passenger side front wheel in the same fashion. Note that the degree of caster should be the same on both sides, with a tolerance of up to one-half -- or more ideally one-quarter -- degree difference between the sides.