The roadster soft top (RST) is a complex system of hydraulic and electrical components. I'm not sure what you are referring to when you reference line #12 ???noticed i have 3 holes in line #12, so does anyone know where to get new lines?
Feel free to go to the bottom of the 4th blue Sticky at the top of the forum and read the last topic about the RST hydraulic system.
It's my guess that due to the age of your car you have one or more leaking hydraulic cylinders due to a internal rubber seal failure. The front two hydraulic cylinders (HC) that usually leak are located in the compartment on top of the wihdscreen or windshield. We have several Do It Yourself (DIY) write ups on how to fix these but when it comes to the other 10 HC's the information is spread throughout the forum. But I have done my best to consolidate most of them into one Thread.
BTW, almost all of the R129's (1989-2001) have the same hydraulic system. Some people will say you have 11 or 12 seperate HC's that move the RST. Regardless, when you own a 1992 your best bet is to replace ALL 12 of the HC seals rather than one at a time due to the amout of labor involvd.
When you fix one or two that usually puts pressure on the other old HC's and they will usually fail shortly thereafter. There are several ways to fix this problem on a 1992 R129. One is to set the car on fire and collect the car insurance, the other is to have the work done by a MB Dealer or Independent (Indy) repair technician. Note: most Indy's don't know how to do it unless you find the right guy and most dealers will charge you about $10K-$12K to replace all 12 of the HC's with new parts and labor. The other way is to have the cylinders rebuilt, don't buy used, or you can buy new parts or rebuild them yourself and replace all of the cylinders yourself.
We have several people on this forum that have done so. If you go to the For Sale and Want to Buy thread in the blue Stickies you will find that there is a a fellow buy the name of 'KBlov" that has a whole set of seals 4 sale so that you can rebuild your own.