Lisle (brand name)sells two small hose clamps ($10 dollars for two) that I used to pinch off the fuel lines off before removing them. I really recommend this as it made the job much cleaner ..didn't lose any fuel. On the W210 there are four lines to remove and replace. The top rear one has no clamp and pulls off easily and is just for air. The bottom rear line goes to the engine (it loops forward as you can see ) and is charged with gas. The bottom forward line is from the pump to the filter ,also charged with fuel and the top forward facing line is a return line to the tank. I really recommend using pinch off clamps on all three lines it will make the job much easier. Also , I pulled the fuse for the pump (#6 under the seat) and ran the car to depressurize the pump and released the fuel cap and then replaced it. I disconnected the battery to guard agianst electrical sparks. Use a flashlight not a halogen or trouble light ..they get too hot. An easy job if you pinch off the lines ...a dirty and dangerous job if you don't. If original clamps on replace them with fuel line hose clamps about 50 cents each ..get them before starting the job.