I have a Mazda CX-9/280k which needed passenger lower control arm ball joint replaced. The job went fine, however after completion, I was packing up the tools and had the dreaded moment when you find there is something I had forgotten on the cart.
In this case it was a little stainless steel washer (?) which goes between the hub and the ball-joint:
What is the purpose of this part? Do I need to revisit the job, to reinsert it? Currently the install looks like:
Update: Below is the other size. It just slides over the top of the ball-joint: