You may well have been told that you have “MacPherson Struts” on your vehicle and wondered at the dealership or big box store automotive service department tech writer what on earth are these car parts and how do they differ from good old fashioned ( and inexpensive ) auto shock absorbers.
It is relatively easy to spot if you do have MacPherson Struts. A suspension system with Macs can be easily identified by even automotive repair novices by looking for a very heavy and thick tube shape strut attached to the wheel assembly at the base and slanting upwards away from the wheel. A coil spring is visible from the outside of the strut at the top, and an A-shaped arm running horizontally from the base of the strut so its’ too legs attach to the frame.
When the MacPherson strut has the spring around the strut assembly, the shock absorber spindle and spring is sometimes a combined unit held in place at the top by the upper mount assembly and at the bottom by the ball joint and lower control arm. The shock absorber is actually built into the MacPherson struts’ outer housing. The coil spring itself is held in place by a lower seat welded to the strut casing and an upper seat bolted to the shock-absorber piston rod. In turn the upper mount bolts to your car, truck, and bus or S.U.V. body.
Any looseness in the control-arm bushings, ball joint, or strut-rod bushings or stabilizer bar links would mean replacement. The strut assembly itself should be checked closely for spring fatigue, poor damping characteristics, binding and popping that may well occur when the wheels are turned or rolled – should be checked between for leaks between the shock shaft and shaft housing. By bouncing the suspension, check for binding which indicates a possible bent shock absorber shaft. If any of these conditions exist the strut will have to be taken apart for service and this is a job for which any back yard mechanic should really seek auto mechanic professional help and assistance