Two questions for the brain trust

[Henn28]

Gents,
My "4.6i" is slowly coming back together. I had a few hours yesterday to torque the new tension strut through-bolts while the car is on the ground for another day or so, finger tight all the steering banjo bolts with new crush washers and several new hoses and install the intake...again. I had put it all together and installed it with the motor out, then realized that getting to the top 3 or 4 transmission bolts would be very, very difficult with the intake on.

I made my life hard by leaving the oil separator on the intake and plumbed. Eventually I was able to get it all back in place. I did have to run the smaller/thin tube under the water pipes in the valley as the intake wouldn't sit down fully with it laying on top of them. It looks like the tube I received is a newer one which replaces an original version of this tube which had more kinks and bends formed into it, I'm assuming so it would lay across the tops of the water pipes. Tomorrow I'll try to figure out why I don't see a transmission breather behind the engine, and if I can do anything about it like run some spare vacuum line. I suspect the shop that installed the rebuilt tranny a couple years ago found it broken and didn't re-install it. Then I'll get the cleaned up wiring harness back on and plugged into the injectors and coils (waiting on my DME to come back from getting a 4.6 flash), and run the new oil lines with AN connectors to the new CSF oil cooler. Then I'll run the belts. I think I'm going to re-route the heavy power line that comes up the left side of the motor and across the heads, back to the jumper stud. I'd like the valley cleaner so I may run it up the left side of the engine bay.

At any rate, I have two questions maybe someone can help with:
- When i was pulling the old motor out I found what I think is a vacuum line, badly deteriorated. I can see that it comes out of the left sidewall, by the heater valves as a plastic hard-line, then a rubber line seemed to run across to the valley, take a 90 degree turn and run to the front of the motor. I only found the plastic 90, and bits of rotten rubber hose so I don't know where this goes or what it was for. I suspect fuel venting/recovery maybe.

- My second question is regarding the power steering reservoir cap O-ring. Lots of leaks on mine over the years so I ordered a new O-ring along with several new hoses. Turns out I can't figure out how to get the O-ring on...seriously. No grove to accept it on the cap or in the reservoir neck, or will it sit nicely at the base of the threads. Perhaps this is why my cap didn't have an O-ring on it when I yanked the reservoirs out for the motor swap. RealOEM clearly shows an O-ring, but I can't get it to fit. Anyone run into this.

Pic of the deteriorated line where it slips over the hard line and disappears into a void on the left side of the engine bay.

My VIN is: 5uxfb335x2lh36976

Thanks all