the usaual route is to remove and replace bearing with a hydrolic press as the are difficult to remove without one. they can also be tricky to replace as your not meant to tap the bearing into place as it could damage it. you can make a make shift tool using a long bolt and some big washers and a relivant size tube to wind the bearing into position as i have done on my rs2k 4x4 before. just depends weather you are confident enough to give it ago. my drive shafts were easy to remove, undo the lower arm balljoint pinch bolt, seperate the balljoint from the hub, undone the center nut and gave it a tap and it poped out. not sure if thats the case on your r/w/d merc. not sure if you would have half shafts or drive shafts on it.