The front suspension has 2 primary purposes:
Isolate the driver from irregularities in the roadsurface.Define the ride and handling characteristics of thevehicle.The front suspension absorbs the impact of the tirestravelling over irregular road surfaces and dissipates this energythroughout the suspension system. This process isolates the vehicleoccupants from the road surface. The rate at which the suspensiondissipates the energy and the amount of energy that is absorbed ishow the suspension defines the vehicles ride characteristics. Ridecharacteristics are designed into the suspension system and are notadjustable. The ride characteristics are mentioned in thisdescription in order to aid in the understanding of the functionsof the suspension system. The suspension system must allow for thevertical movement of the tire and wheel assembly as the vehicletravels over irregular road surfaces while maintaining the tire'shorizontal relationship to the road.
This requires that the steering knuckle be suspended betweena lower control arm and a strut assembly. The lower control armattaches from the steering knuckle at the outermost point of thecontrol arm. The attachment is through a ball and socket typejoint. The innermost end of the control arm attached at 2 points tothe vehicle frame through semi-rigid bushings. The upper portion ofthe steering knuckle is attached to a strut assembly. The strutassembly then connects to the vehicle body by way of an upperbearing. The steering knuckle is allowed to travel up and downindependent of the vehicle body structure and frame.
This up and down motion of the steering knuckle as thevehicle travels over bumps is absorbed predominantly by the coilspring. This spring is retained under tension over the strutassembly. A strut is used in conjunction with this system in orderto dampen out the oscillations of the coil spring. A strut is abasic hydraulic cylinder. The strut is filled with oil and has amoveable shaft that connects to a piston inside the strut. Valvesinside the shock absorber offer resistance to oil flow andconsequently inhibit rapid movement of the piston and shaft. Eachend of the shock absorber is connected in such a fashion to utilizethis recoil action of a spring alone. Each end of the strut isdesigned as the connection point of the suspension system to thevehicle and acts as the coil spring seat. This allows the strut toutilize the dampening action to reduce the recoil of a springalone. The lower control arm is allowed to pivot at the vehicleframe in a vertical fashion. The ball joint allows the steeringknuckle to maintain the perpendicular relationship to the roadsurface.
Front suspensions systems utilize a stabilizer shaft. Thestabilizer bar connects between the left and right lower controlarm assemblies through the stabilizer link and stabilizer shaftinsulators. This bar controls the amount of independent movement ofthe suspension when the vehicle turns. Limiting the independentmovement defines the vehicles handling characteristics onturns.
Tools and Equipment
Special tools are listed and illustrated throughout thissection, with a complete listing at the end of the section. Thesetools, or their equivalents, are designed to quickly and safelyaccomplish the operations for which they are intended. The use ofthese special tools also minimize possible damage t ...