Recently on my 82' 300 sd the brakes require a lot of pressure on the pedal in order to operate effectiveley. I am wondering how would i go about determining whether this a result of the vacuum pump or the brake booster itself? I must also mention that this is only a problem when the engine is relativeley cold. After i drive for 4 or 5 minutes the problem goes away. My car also doesnt like to shut off when its cold, but equally this problem disapears as long as the engine warms up. The vacuum lines have been recently replaced and i checked them just yesterday and from my observation they seem to be fine. So what are the possibilities?

__________________
1983 300SD White with Grey interior

If your transmission started shifting hard at the same time, and/or the car does not shut-off promptly, than its probably vacuum related. If no change in the above, than its probably break booster related.

As you don't have a vacuum gauge, use the above as a rough guideline only, not as an accurate diagnostic.

Phil

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

The first tests should be made at the vacuum pump.

See what you get for vacuum when you first start it.

Then, check for vacuum after it fully warms up.

If the pump is the culprit, you will see the difference on the gauge readings.