correct center cluste (oil pressure wire) removal

[rmmchl]

i removed my center cluster to send it of to fix the temp gauge----------I could not screw off the frozen screw that holds the oil pressure gauge wire on-I had to remove the nuts at the bracket on the brake booster. I disconnected it at the actual rubber hose that goes to the oil filter apparatus. I then pulled it through the firewall. What is the correct way?-maybe this is correct--It worked------I am going to have north hollywood speedo un-freeze the nut that holds the temp gauge wire on, since i'm sending it to them also-Any feedback from anyone would be appreciated

[J. Huber]

Ideally, the oil line stays in place and just unscrews at the gauge. The temperature wire (capillary) is usually the one that stays connected to the unit -- it is loosened at the block and pulled through the dash (carefully)...

When unhooking the oil-line, it is the smaller nut that turns, the large one stays connected to the temperature cluster unit. What I did was hold the large one (14mm) with one wrench and turn the other with a smaller wrench (10mm?). The trick is to turn it lefty-loosy as if you are facing the car from the front. Not sure if this helps.

[rmmchl]

the little nut was froze up and I tried every metric and sae wrench-----------------none fit it well-I have no idea where mercedes found that nut-Its somehwere between a 10 and 11 mm -thats why i had to leave it on and disconnect it from the bracket by the brake booster-------------Hollywood speedo said he would free it up and put some lub on it , so it wouldnt happen again, if I ever needed to take it off-your comments have helped-you know what you are talking about-and seem to know the problem i ran into

[glenn]

Both the oil and temperature lines are tubes-tubing-, not wires.  The temperature capillary is encased in wire mesh protection.  It connects the bulb(pencil sized) in the block end with the bourdon tube on the dash.  It is a 'filled thermal' system.  As the fluid expands with heat, it rotates the pointer on the dash.   After 40+ years it is tough to loosen the bulb at the block.   Be careful-------.  Break the tubing, buy the farm.