If I may add, the hardest part is handling the little "C" hooks that hold the seat cover on to the foam/padding underneath. I used large needle-nose pliers.
What you need to know is:
Is the frame/springs OK. You can reach under the seat and look/feel for broken springs. Do even bother tying to fix them. Been there, done that. Get new seat bottom.
Padding/cushion- If never been replaced, just replace it.
Cover- If it isn't torn or ripped, it should be OK with one area to check- If you have the MBtext with the pronouced ribs running front and rear (vehicle orientation) they may have slid down towards the back of the seat (hinge area). I found that moving them back, using hot glue and several heavy-duty threaded sitches works great.
To remove the cover, you have to compress the seat covering edges all around. Best to do when the seat is upside down and it is elivated on something about 1-1 1/2 feet high. Start with the back and you will see how there is a cardboard edge attached to the seat covering that needs to be pushed down (seat upside down) and it will come out of a grove that is all around the seat edge.
There is hardly anything more satisfying than doing this, especially when the seats have gotten quite bad!
Hope this helps.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)