Len Sokoloff / firstname.lastname@example.org
This job is covered in the shop manual (SM1207 / Service Manual for the 190 Series) under Section 46-6, Removal and Installation of Sealing Rings in Steering. It is only half a page long, but refers you to a couple of other sections that go on forever. This write-up covers the information that was gathered from my own experience doing this job on my 1959 220S cabriolet, along with input from James Davis, Henry Magno, Ed Richardson and Will Samples.
Parts you will need to reseal your steering box
- Sealing ring at the front of the wire tube, 120 997 10 40, cost $4.20
- Sealing ring at the rear of the wire tube, 120 997 11 40, cost $7.75
- Sealing ring in adjusting ring, B20 x 32 x 7, DIN6504, which may now be part number 001 997 40 40, cost $3.00
- Sealing ring at the base of the housing, 000 997 48 46, cost $5.25
- Gasket for steering box top, 120 461 05 80, cost $3.50
- Optionally, you may want to replace: Rubber joint disk, 121 462 00 46, cost $27.75
Sealants and grease to use
- Wheel bearing grease for the pressure sleeve, pressure spring
- Loctite on the seals to be safe
- #2 Permatex flexible black on anything that calls for sealing compound
You've got to have a vise. Some of the nuts are so large and so tight that trying to steady it by hand just will not work.
Tools that might not be in your toolbox that you will probably need
- Ball joint separator and pitman arm puller
- A BIG adjustable wrench that opens to about 54mm for the adjusting ring hex nut
- A 38mm socket/wrench for the hex nut in the cover. An adjustable wrench might also work
- A pin wrench, also called a spanner wrench, for the adjusting ring. Some people have gotten it off by using needle nose pliers, but I would have the proper tool on hand to be sure.
- A 22mm or 23mm wrench for the wire tube nut — an adjustable wrench will work too
- A 32mm socket for the castle nut that holds the gear arm on — an adjustable wrench will work too
Mark the starting locations of absolutely everything so that you can reassemble things properly. Scribe the parts, put a dab of paint on them, anything, just so you know how they go back together. Make notes of anything that might be able to go back together incorrectly or if you might spread the job out over several days or more. This includes the steering wheel since it can turn freely once the steering is disconnected.