This part is listed by BMW as BMW part number 32411138803 (32-41-1-138-803) and is described as a OEM Pressure Hose for Power Steering on E36 325i, 325is, M3 S50, M3 S52, and MZ3 S52.
This runs from the power steering pump to the steering rack. At either end is a hard metal line secured with a bolt and copper crush washer. The hose has extra length so the system can have more fluid capacity. Unfortunately it has a lot fittings where rubber hose meets metal line. These fittings are compression crimp-style swage ("swedge") fittings that are very common in the automotive world. These swage fittings are the most common area for PS leaks on your BMW. It's easier to replace the entire line with a new OEM or BMW part than to try and repair the line.
Chances are very good that one or more of your E36 and Z3 power steering hoses are leaking. Power steering leaks are a not uncommon trait of BMW ownership. Most of the leaks can be traced to old hoses and fittings that have been in service for too long. Just like cooling hoses and belts, rubber power steering lines need periodic replacement. Don't wait too long to replace a leaking power steering line! It's only going to get worse and coat the underside of your engine in dirty oil. Replace them before they fail in order to save you from further headaches and expenses.
Supersedes the following BMW part numbers:
32411138397 (32-41-1-138-397)
32411141953 (32-41-1-141-953)
This is a power steering hose manufactured by Cohline - an original supplier to BMW for many engine components. As an OEM, Rein meets all of BMW's original design, fitment, and performance requirements and is TUV approved. OEM parts are the best alternative to more expensive Original BMW parts because they are virtually identical without the inflated price tag. This part has a two year warranty.
BMW Fitments:
3 Series
E36 (92-99) > 325i
E36 (92-99) > 325ic
E36 (92-99) > 325is
E36 (92-99) > M3 (1995)
E36 (92-99) > M3 (96-99)
Z Series
E36/7 / E36/8 Z3 (96-02) > Z3 M - S52