I just replaced the oil pressure line in my '84 300Dturbo. The new one I bought is hard plastic with a brass fitting on each end. About half of the line had a hard rubber tube over it - maybe to protect it. The line also had a big rubber boot for the firewall opening, with lots of holes for the vacuum lines. I pulled the boot off and forced the gauge end of the line through the old boot (didn't want to mess with the vacuum lines).

After removing the panel under the steering column I was able to remove the old line/attach the new one to the oil pressure gauge without pulling the instrument cluster.

Think I'd change the whole line if I were you. If you think the oil's a mess in your driveway, wait until it pumps onto your carpet!

fmb