Q: I replaced the lower ball joint, but when I try to tighten the nut, the ball joint stud just turns

A lot of times, when you’re installing a ball joint into the lower control arm and trying to tighten the nut to lock in the ball joint shaft, the shaft will spin if you do not have enough pressure on the lower control arm. You will need to use a jack under the control arm as close to the ball joint as possible to push up on the joint so that the weight of the vehicle pushes the ball joint tight; then you should be able to tighten it. Make sure when using a jack under the lower control arm that you keep the vehicle supported with jack stands. If you need any professional assistance with this repair, you can always contact a certified technician, such as one from YourMechanic.