Rear suspension problem for FWD Vibe base model. Rear wheels are cambering in?

What is your question?

Car has 218k and running great. well maintained. noticed the rear wheels (solid axle) are cambering in (almost like the axle is weakening), so the tires are wearing the inside edge. with a solid axle, dont understand how this can be happening! what a bummer. any fixes out there? shim the drums? replace the axle? I am trying to get to 250k! Thank you in advance.