Alright, for a little while now i have noticed that my 82 300 sd has power break problems, hard shifting, and automatic shutoff problems when the car is still relativeley cold. After doing a few searches on this site I have diagnosed it as the vaccuum pump, but I still dont have enough experience to gauge the situation. Should I just rebuild it or should I go ahead and get a new one? After the car warms up a bit and the vaccuum builds, everything operates fine so i have really been avoiding the problem for a little while now, but i feel like this might lead to problems. As i have read, the timing chain might be at risk, is this true? Any comments help or suggestions would be greatly appreciated.

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1983 300SD White with Grey interior

Unless the vacuum pump housing is damaged, there is no reason not to rebuild the pump. But first you need to ensure that you don't have a vacuum leak(s) that is causing the problems you described. Also, the check valve on the top of the vacuum pump can produce symptoms similar to a bad vacuum pump. Check that also.

If you have a vacuum line going to the center of the top of your airfilter then check to see if you have any oil showing in it ... or on the inside of your airfilter....
This might indicate just a torn diaphram. A relatively simple job on one of the types.
There are at least two types of vacuum pumps and I don't know which you have. One type is much more expensive to just buy outright... and the other costs less for the repair kit.
But it seems that one type, if they give way inside have the potential for harming your engine....

The 1982 300SD has the pump with a piston, not the one with a diaphram.

Your vacuum pump is similar to mine. It sounds as if you might have a check valve leaking inside. I experienced similar problems before installing a rebuild kit. Have you stuck a vacuum guage on the system to see what it is after start up?

More than likely, you just need a rebuild kit with just the check valves and seal. ("late model kit" I believe is the correct one) It is pretty hard to tell if you need the major parts until you have it apart but I think you might hear quite a bit of racket if this was the case.

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Sam

84 300SD 350K+ miles ( Blue Belle )

I TOLD you I did not know...
Does it have check valves instead ?
Is that the expensive one to buy outright ?

Yes on both counts.

I do have a lot of oil in the air filter. Ill check the valve at the top of the pump housing, if this is bad how will i know and should I just replace it? Is the rebuild pretty straightforward or will i need any special tools? Unfortunatley I dont have a vaccuum gauge to test the line after startup. I might go ahead and replace all the vaccuum lines if im gonna rebuild it and just get that out of the way to prevent a future problem and or headache. thanks guys for all the posts thus far.

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1983 300SD White with Grey interior

This is a good guide to pump overhaul:
http://business.baylor.edu/Richard_Easley/autofaqs/Vacuum%20Pump/Rebuild_vac_pump.htm
The check valve on the top of the pump can be removed with the pump still installed on the engine. First remove the vacuum line at the pump. Then remove the fitting where the line attached. The check valve in the fitting should allow air to flow in the direction of the pump, but not the other way. (Sometimes the internal parts of the check valve will fall out in your hand.) Failure of the check valve will present similar symptoms as a failure of the pump itself. If there is an Autozone store near you, you can borrow a Mityvac for no charge. With the gauge, you can determine quickly whether your problem is with the pump or elsewhere. Otherwise, you can disconnect the vacuum line at the pump or brake booster and get a rough idea if the pump is working by placing you thumb over the end of the line.
Regarding the oil in the air filter, it is not related to the vacuum pump on your particular model.