This was more difficult than I had hoped, maybe it was just an off day.
Removing the driver's seat was only helpful in morale since it allows you to see the top bolt that you have to unscrew, but you can't get your hand down there to do anything about it. I would say it would be near impossible to replace this hose with the oil filter in the way, so you'll want to do this during an oil change. I picked up a new line that came with the copper washers from CCAutos.
1. Drain oil
2. Remove oil filter
3. Unbolt lower part of the Vacuum pump oil line (17mm; lower green circle, image taken from under the van)
4. Unbolt upper part of the Vacuum pump oil line (upper green circle above). This is also a 17 mm bolt. I was able to get my 17mm wrench (8" long) in there without issue.
Other posts I found on this said you need a short wrench and it may be hard to get a ratcheting wrench in there as the bolt is close to other parts of the engine. While you are unbolting this, you might think to yourself, this is going to be a real pain to get back in here, and you might be right.
5. The difficult part of replacing this line is that you have washers on either side of the bolt that goes through the eye of the oil line, and the washer on the outside of the bolt wants to fall off. On top of that, you have to keep this together while getting your hand back up into the engine at an angle where you don't drop either the bolt or washer or all of it, and are at the correct angle for screwing this into a hidden hole. I'm pretty sure the last person to install mine didn't get the outer washer on because I never found it on the old bolt and it wasn't stuck to the engine side. By feel, it seems there are also other holes up there that you can't bolt into, but deceive you into thinking you can. After about an hour and a brief lunch break and a little more time trying to get it assembled, I began thinking I would never get this tiny hose replaced. I decided maybe I should change my approach, so I got out from under the driver's side of the van and crawled in from under the passenger side. Basically reversing my point of view, and suddenly, and magically, my left arm was all the way in the van and immediately found the hole and began screwing the bolt in. Amazing. I had thought I had the best approach initially, my feet sticking out perpendicular from the driver side of the van, but if you're having trouble with this, try changing positions. I think I ultimately had my feet towards rear passenger side tire and got the bolt into position with my left arm, I can't be sure, I think I blacked out.
6. Once you have the top bolt in, have a beer, (green circle below, image taken from above with driver seat removed), fit the bottom bolt in, but make sure the hose isn't rubbing again the engine anywhere, which could cause premature wear and tear.
7. Replace oil filter (green arrow).
8. Finish your oil change.
