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1984 300sd Vacuum Readings

Submitted by Rafe E. Phipps on 9 March 2010 - 12:59pm.

1984 300sd: Need to know vacuum spec. readings other than the'ol 20-23"
from the main vacuum hose.

Does anyone know the readings to:

transmission modulator value= 15-20"?

shutoff valve value= NEED THIS ONE

door actuator value

ignition switch

door check valve at firewall

Are the readings all suppose to be the same? 20-23 in of vacuum

I have Kent's books but do not see vacuum readings at the different branches of different systems aforementioned.

Thanks, Rafe.

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Vacuum readings

10 March 2010 - 1:41pm
admin

Hi Rafe, the only component in the system that receives regulated vacuum is the transmission modulator. Troubleshooting the transmission shift vacuum control valve (VCV) is a little more complex and will be available in my transmission tuning manual out soon. All the other components received full vacuum pressure 21+ inches. (although your readings may be slightly less due to line deterioration or minor leaks). Kent

Vacuum readings

12 March 2010 - 8:04am
Rafe E. Phipps

Thanks Kent for all your wisdom, and time that you provide for all of us. Anyway, I followed your book and the main pump is strong at 23" and the vacuum shutoff valve was slow to shut down and is leaking oil. I will replace the shutoff valve bought from mercedessource, and will probably test my ignition line if it does not shutdown or is slow to shut down. I fear oil has invaded some lines of interest seeing that I pulled some thru my mity-vac. Funny thing was, the first time I pumped the mity-vac it shut down quickly and then a second time, I turned the key off and it took some pumping to get it to quit.
Anything I'm missing let me know, will update...
Thanks again for all you do up there in Mercedes-Land, :)

Rafe.