I recently replaced the evaporator and 6 vacuum pods on my 1993 400E. Here are reflections on the work I did on my car that may apply to yours as well.

See http://photos.wanadoo.co.uk/album/1259925 for pictures of a W124 dash removal.

Very carefully read all posts on the thread, “Help W124 Evaporator” by Jcyuhn, he is very knowledgeable.

A T-27 Torx bit with a minimum 2 inch long shank was needed for removing the steering wheel air bag

Three new o-rings for lines going into heater core were needed.

Two new o-rings for lines into expansion valve were needed.

Four new o-rings were needed for the new receiver/dryer.

I needed two new foam condensate drain lines from Mercedes or, as a much cheaper alternative, I used about 10 inches of 3/4 inch ID vinyl hose.

PAG oil was specified for lubricating heater and air conditioner o-rings. I bought an 8.5 ounce can at Advance Autoparts for about $6.50. Approximately four ounces of the PAG46 oil was also added to the system prior to evacuation and recharging.

I did not take enough photographs of the disassembly; sometimes had to reply on faulty memory.

I did not always bag and label all fasteners and ended up with leftovers.

I removed the center and left hand air vents before trying to remove the instrument cluster. With the vents removed, the cluster was gripped with fingers at each side and wiggled out without the use of the cluster removal tools.

There was a difficult to open, postage stamp size door on the center vent that retains the bulb and its holder.

The rocker switch assembly was removed by gently pushing it laterally to the left, or right, and then gently pulling it straight back.

I needed to more carefully record location of vacuum lines from the plastic manifold, on the right side of heater box, to the pods. I got them mixed up.

I found that clips holding together the heater box, tended to jump like frogs during removal.

I loosened the clamp holding the low pressure refrigerant line located on the forward firewall to get a little more wiggle room when trying to fit the line into the hole in the expansion valve.