As far as muscle cars are concerned, the GM A-Body’s chassis was perfectly structured to ensure brilliant straight-line cruising. The front sway bar provided sufficient leverage to ease some of the car’s body lean during a turn, while the rubber bushings in the suspension could limit noise, harshness, and vibrations.
Why upgrade chassis suspension?
Like Robert St Thomas will tell you, cars also age with time, along with the suspension’s rubber bushings, which renders them into marginal performers from originally mediocre components. But the people behind the development of the Pontiac GTO didn’t want the same happening to their car. They realized it was possible to go a step further than replacing old bushings with new ones in a vintage Pontiac GTO. Doing so would help to improve the chassis and maintain a stock exterior look.
Rear Suspension Rebuild
The very first thing is to mark the locations for attaching the new sway bar on the lower control arms. Afterwards, the shocks, flexible brake line, rear universal joint, and upper and lower arms, are disconnected that drops the total rear axle out of the car. Using a drill press it is possible to bore holes in the lower arms for the sway bar mount, while a hydraulic press does a fine job of removing bushings.
Front Suspension Rebuild
Disassembling front suspensions are way trickier due to the size of the steering components, ball joints, and springs. The first step is to remove the brake rotors, followed by loosening the nuts attach the spindles to the ball joints. The spindle is removed along with the retaining nuts of the spring. Take out ball joints in order to strip front control arms. The lower ball joints are a press-in design that uses the pressure of the front spring to aid in retention. Using a hydraulic press, they can be pressed out in a similar method as the suspension bushings.
After the arms are cleaned and coated with powder, the new ball joints and bushings have to be reassembled. The spindle from the upper arm is disconnected, while the uncompressed spring is held in its upper pocket seat. Once the top of the spring is seated, the inner side of the spring is marked. The spring is compressed to the measurement taken from seat to seat–no more than needed for the installation. After compression, the spring is gently slid into the upper pocket, while the lower arm is moved in the up position and retaining nuts are attached to the spindle. Please note that all the attaching bolts for front suspension components are just finger tight as it aids in facilitating spring installation.
Finishing the Task
After disassembling the front suspension of a vintage GTO, it will come to notice that there is an overly large amount of oddly stacked alignment shims. Without a doubt it is to make up for a raft of worn components – don’t hesitate to take the car to an alignment shop for this purpose. Prior to alignment, all pivot point bushings are tightened with the car, at the normal ride height. After the alignment is complete, the components are double-checked to guarantee the degree of tightness. The GTO’s handling makes a significant jump from unpredictable to well-mannered. There won’t be any need for continuous, trivial adjustments to the steering when you drive in a straight line – no more squeaks, groans, or funny noises.
Replacing Bushings
Using a large vise, you can replace some of the suspension bushings, but it is advisable to utilize a hydraulic press. The holes in the arm for the bushings are stamped with a flange for retaining the bushing. These holes are stepped to let the bushing slide smoothly through the opening – it has two varied outside diameters, and fit in snugly on both ends.
Lastly, factory-style rubber bushings would have improved the GTO’s road manners, but polygraphite bushings are suggested as a better alternative.