Hello...
Here you might se this picture.
http://home.no.net/smalerba/mb/steeri1.jpg
Start with unscrew 160
Lift 158 up and 155 will be mounted on 158.
Then unscrew 149 and lift 146 and 143 up.
The filter (137) is in the bottom of the container.
When you perform this also renew the oil, using Mercedes-Benz steering gear oil.
What gaskets to renew i don’t know, it is only 155 and 128 that is gaskets, but i always say, never repair something that works.
But you might want to change them if there are any leaks.
Partnumbers.
155 upper gasket 000 466 16 80
137 Filter 000 466 21 06 optional with 000 466 16 04
128 Seal ring 022 997 19 48
Steering gear oil 000 989 88 03
Good luck.