1999 BMW 740iL Suspension System Inspect Cost

Suspension systems have existed long before automobiles were invented, and still serve the same function. Albeit they have become much more advanced, the basic functions are to support the body of the vehicle and absorb the impact and vibrations encountered while driving. Modern vehicles have enhanced this focus to include improved handling characteristics, increase body control in many conditions, and allow the vehicle to traverse even the worst terrains. Being as the entire weight of the vehicle rests on the suspension, these issues manifest themselves in obvious manners. When an problem presents itself, a suspension inspection will likely identify the issue right away.

The suspension system operates based on spring pressure and moveable components. Spring pressure allows the suspension to hold the weight of the vehicle, and keeps the vehicle in a raised position. This spring pressure may lift the vehicle by a control arm of the wheel spindle, but in either case it performs the same function. The suspension must absorb shock and flex over bumps, so moving joints are used in most areas of the suspension system. To allow the wheels to move up and down, control arms are secured to the chassis and allowed to pivot up and down. Next, the spindles connect to the control arms vie flexible joints called ball joints, which allow the spindles to turn for steering wheels, and prevent binding when the control arm moves up and down. Next, sway bars are used to connect the control arms on both sides of the vehicle and the frame of the vehicle. This flexible bar prevents the control arm on one side of the vehicle from moving without the other control arm compensating as well. This allows for controlled turns with limited body roll. Finally, shocks are used, either between the control arm and frame or as part of a strut assembly, to dampen the movement of the suspension and control bouncing motions. This entire system can be much more complicated, so when a suspension problem presents itself, inspection will be necessary to identify the cause.