[ngoma]

This has been frequently and extensively discussed on turbobricks.com and brickboard.com. Suggest you can search there.

From what I remember, you can press out and install the bushings with some homemade tools out of lengths of allthread rod, large sockets, washers, pvc pipes, etc. The trailing arms can deform and cave in as there is not enough reinforcement around the bushings so they like to weld in reinforcing plates.