I have a 67 Impala with a 12 bolt. What I can't find anywhere is what the procedure is to remove the lower, or upper, rear control arms safely with the wheels on. Does the rear need lifted off the ground or can the wheels be setting on the ground with the weight on, say up on ramps where I can get under it. I see one rear bushing on a lower control arm that needs replaced so I want to take the lower arm off and replace the bushings. I want to do it safely and I'm not sure what the physics are when I remove the bolt, whether the control arm will just set there or will there be pressure on it that will let it drop hard or something. So my question is, what's the procedure to get the Impala ready to remove the control arm? Thanks.