Extend the steering wheel, insert a hook into either side of the gauge cluster housing, pull out enough to get to the wires, pull off all the wires, remove gauge cluster housing.

You can get hooks for as much as $25 a pair but I have hooks I made from a dry cleaner wire hanger. Cut 2 12" sections, straighten, bend a 1cm barb on one end of each length, form an acute angle with the main stem, curl the other ends into something you can grip. If you clock the handles relative to the barbs it'll be easier to position the handles. So then run the hooks into both sides of the gauge cluster housing about halfway up. Go in about 4" then turn the barbs inward. Pull firmly on the hooks to release and extract the gauge cluster housing. It might help to rock it out. The dash hump is surprisingly resilient or I've been lucky

Clean all the bulbs with alcohol while you have the gauge cluster out. You might consider painting the needles so they're all a uniform color again. Check also the posts (including a couple I started) on using a gasser economy/vacuum gauge as a boost gauge.

Good time to install better dash speakers.

Sixto
95 S420
87 300SDL