This part is listed by BMW as BMW part number 32416778235 (32 41 6 778 235) and is described as a Power Steering Pressure Hose for E82 135i, E9X 335i with Active Steering.
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.
This is a Genuine BMW E9X PS hose with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.
For full BMW fitment information or for assistance from one of our BMW experts, we recommend calling us at 877-639-9648.
BMW Fitments:
1 Series
E82 / E88 (08-13) > 135i N54 (08-10)
E82 / E88 (08-13) > 135i N55 (11-13)
E82 / E88 (08-13) > 135is N55 (11-13)
3 Series
E90 / E91 / E92 / E93 (06-13) > 335i N54 (07-10)
E90 / E91 / E92 / E93 (06-13) > 335i N55 (11-13)
E90 / E91 / E92 / E93 (06-13) > 335is N54