Mercedes suggests using "pulling hooks" that are wire hooks with plastic
handles to yank the instrument cluster from the dash. That method will
almost guarantee that the speedo cable will be stretched and the needle will
bounce at low speed.
My method is to remove the under dash panel. Then remove the black plastic
air ducting that connects the center console to the driver's side vent. The
ducting is snap fit into place and easy to remove and replace. With the
ducting out of the way, feel for the speedo cable end and undo it before
pushing the cluster assembly out towards the steering wheel. The steering
wheel does not have to be removed. The wiring to the back of the cluster is
unique plug coded so there is no chance to reattach the wires improperly.
On pre-85 cars, the oil pressure gauge was fed with a "live" oil line, but
later models are electric.
There are two wedge bulbs that provide illumination for the cluster. It's a
good ideal to change out the other warning lamps at the same time.