Why are you loosening the motor mount bolts? It has been a while since I did subframe mounts on a 108 chassis but I know we did them one side at a time and I don't think we removed the tierods. We definitely used the weight of the motor to help drop each side. A jack handle also helped to pry down the subframe briefly for removal and installation.
If you have to remove the tierod there is a puller that will do it without tearing the boots as a picklefork will.
Bosch Master, ASE Master, L1
33 years MB technician