Referred to as a wishbone by BMW This lower control arm bolts to the subframe and is secured to the wheel carrier/spindle by the integrated ball joint. This lower control arm essentially "locates" the front suspension and helps maintain correct suspension geometry. The two most common failures of this control arm are inner bushing failure and outer ball joint failure. Any play between the inner bushing or outer ball joint can have a detrimental effect on handling, alignment, and safety. FCP Euro recommends replacing control arms in matched pairs for the best performance and service life.