I have a 1980 300sd with a failed AC and Heating system.

A week or two ago, I posted a question about identifying the proper servo unit in the junk yard and received very helpful responses.

So far, I have not made it to the junk yard but am going this week or next. Last night, the thought occured to me that maybe after finding one (if I am lucky), it might not solve my problem.

Would someone here describe the functions of a servo and the effects of a failed servo?

Also, what model and year of cars might have the newer aluminum bodied unit?

Thanks

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DCM

1977 240d
1980 300sd
1987 Chevrolet Suburban

i have successfully repaired mine.it can be done.its original and still working after 27 years.there are a few tips to keep it running though

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michael cole 1980 300SD gone now but not forgotten,87tdt,90 300te 4matic 95 e320 wagon

Are there kits available for repair of the servo?

Thanks

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DCM

1977 240d
1980 300sd
1987 Chevrolet Suburban

It is basically a large arm that swtiches electrical and vacuum signals manually to the klima system. It sits on the valve that controls whether coolant will be fed into the cabin. Usually what happens is the coolant freezes and bursts. First thing I would do is start up the car drive around for 15min or so and then turn it off. You SHOULD hear the servo moving.

What specific problem are you having? GL finding a servo at the yard, they are always the first thing to go.

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

not that im aware of.but if you get a spare from the junkers it may be a source for some parts.certainly it will give you an extra unit that you can disassemble and explore.most common problems are case cracked by overheat,drive motor seized,contact wipers coroded

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michael cole 1980 300SD gone now but not forgotten,87tdt,90 300te 4matic 95 e320 wagon

Don't waste your time, go to Diesel Giant and purchase the digital replacement, spend a couple of hours and be thru with your problems (if you plan to keep your car). It cost a little (or lot, I am retired), but we bought my wife's 77 123 new and plan to keep it, (235K).

Ron Moore