Trunk lock problem on W126

[lakeside]

The trunk lid on my '88 420SEL, will not latch. I think this happened a few years ago and I fixed it by adjusting the catch on the lid, but I can't remember. The catch on the lid shows a lot of wear on the side facing the lid exterior. This suggests that the catch has been rubbing a lot on the locking mechanism. So, I'm about to adjust the catch on the trunk lid and I want to know if there is a way to determine how far I should move it in or out. I can make a guess, but I don't want to end up with the trunk locked and I'm unable to open it. Or, does this indicate a problem other than the catch position? I'd appreciate any tips you all might have.

Edit I moved the lid catch so the trunk lid now locks and opens okay. However, it seems that the vacuum pump runs longer than I recall it every running. The door locks close, as does the trunk lid lock but the pump keeps running after locking. I'm guessing it runs 10 or 15 seconds. Should I be concerned?