I cannot recall anyone saying there was a lot of difficulty removing and re-installing the Turbo Oil Feed Line. The line attaches at the rear bottom of the Oil Filter by way of an banjo bolt and 2 crush washers (over tightening it can crack the plate the Banjo Bolt screws into). There is a clamp (I only remember one clamp but look for another just in case) that I believe holds the line at the rear of the head or intake manifold and the 2 blots where it mounts on the turbo itself.

After that I am guessing you just have to maneuver the line up and out and to the right side of the car.

When I first got my car the engine all the way back to the transmission were layered with oil and dirt to the extent that 3 cans of Engine degreaser still left a good deal of oily dirt on it. However, it was enough to tell that 95% of the Oil leak was coming out of the back of the Valve Cover Gasket. And that is the area you said is leaking.

If the oil feed line is cracked you are likely better off trying to locate a new or used one because that means the metal is crystalized in that area. If a hole is worn into the line there may be some way to fix it depending on where the hole is.

__________________
84 300D, 82 Volvo 244Gl Diesel