Thanks for all your useful information with reguards to changing the #4 body mounts. I had my daughter get in the rear compartment as I loosened the bolt to make sure it was JUST the bolt. Everything went great as far as removing it without the cage nut breaking loose,etc. One problem I did encounter was that a portion of the bracket between the rubber mounts has rusted slightly. I was wondering if I could take a piece of steel, drill out where the mount goes through, and spot weld it to the existing bracket which is fine on the frame. The other #4 mount bracket was fine. If I do do this to the damaged mount would it be necessary to add this to the other mount to maintain proper balance?

I think what you are saying is the hole on the bracket that is welded to the frame is rusted out and needs to be reinforced? Right?.

I believe that welding in a new plate that is drilled on top of the old bracket In my own opinion would be fine. Were only talking about 1/8" steel. The weight of the body is going to create so much compression on the rubber cushions and tightening of the bolts will create so much additional crush. I don't believe there would be anything off balance if so it would be so little I don't think it would even be noticeable. After all the mounts are designed to absorb vibration, allow the frame and body to flex. By nature there is going to be some variance in this type of systems.

Where we run into problems as C3 owners is when the mounts or cushions go away completely allowing for major drop or the body ends up riding on the frame.

What does everyone else think?

That sound right to me. I haven't tried it, but it's logical. 1/8 is not much

Thats what I did on my frame. I had my whole body off so I was able to do it to the #1 and #4 mounts. The hole that the body mount went into on the frame was a big hole. I also made up four "shims" to use on the #2 and #3 mounts to make them all the same but I don't think they made that big of a difference.