I was at the junk yard and there was an 82 300SD there with the IP removed. I found the Vacuum shutoff laying on the ground by the car, I appeared that the person removed the vacuum shut off and also took off outer oil cooler line off of the oil filter housing to remove the IP. The oil filter housing was not touched.
If you are interested to see how the FSM wants you to remove the IP from a 123:
http://www.pauldrayton.com/uploadfiles/merc/Service/W123/Main.html

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84 300D, 82 Volvo 244Gl Diesel