Quick vacum question - PeachParts Mercedes-Benz Forum

adiaw83 · #1 10-26-2006, 04:28 PM

I was just under the hood of my 300SD and noticed one of the lines was completely disconnected. The line runs from near the alda to a part on the passenger side of the engine near the rear of the engine. The picture is the part that the line is connected to on the other end.

1985 300SD Sady · #2 10-29-2006, 08:42 AM

Quote:

Originally Posted by adiaw83

I was just under the hood of my 300SD and noticed one of the lines was completely disconnected. The line runs from near the alda to a part on the passenger side of the engine near the rear of the engine. The picture is the part that the line is connected to on the other end.

This is the line that goes to the banjo bolt on the rear of the intake manifold.

It is not a vacuum line, but a pressure one. It sends the boost signal to the alda which compensates by adding more fuel.

Without this line connected, the alda will not get the signal, and the car will be rather sluggish.

adiaw83 · #3 10-29-2006, 11:17 AM

Thanks a lot for the response. That explains a lot because this car has felt like a freight train lately. Do I need to buy a pressure hose to replace it then? Also I'll probably need a new clamp for th alda. Does anyone have the schematics for the vac system.

Brian Carlton · #4 10-29-2006, 11:22 AM

Quote:

Originally Posted by adiaw83

Thanks a lot for the response. That explains a lot because this car has felt like a freight train lately. Do I need to buy a pressure hose to replace it then? Also I'll probably need a new clamp for th alda. Does anyone have the schematics for the vac system.

Due to the age of the tube, you should probably replace it with a new item that includes the fitting at the end that fits the banjo bolt. The opposite end of the tube connects to the bottom of the overboost protection solenoid on the firewall via a short piece of hose. The ALDA is connected to the top, horizontal port on the overboost protection solenoid via another tube and hose affair.

The vacuum system, which has nothing to do with this discussion, can be found in the DIY resources. It's the common system for all 617's from '81-'84.