Wodnek,

First, all W123 cars came with vacuum locks. If yours do not work at all and the rest of the car's vacuum operated items are working, someone has sealed off the door lock system. That is ok, and the car will work fine. If you want to have the system back, you need to use a vacuum tool to find the problems. The parts are nickel and dime for the most part, but there is some work here and there. Like taking the door interior panels off and so on. Not hard work, but if you are like me, I usually end up breaking some old plastic parts along the way and the job gets bigger before it gets done.

Any feeler gages are fine, although English units will not get the precise gages. Instead, adjust them a little loose since they will close up over time. I find a bigger clearance in Winter helps winter starting.

Always replace the vavle cover gasket when you do the valves, by the way. I usually take the car to a car wash and blast the engine around the valve cover to head joint clear. Makes the job go a little faster. I also use a very stiff synthetic grease (such as for disc brake parts that comes in a small squeeze bottle from NAPA) to seal the valve cover gasket to the valve cover and head. It helps fill in the small gaps that will let hot synthetic oil seep by. Do a search on the subject and you will find lots of helpful data, kind of "Virtual Experience" for the DIYer.

Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)