My 300D W123 (1985) has developed an annoying vacuum leak that
prevents the central locking system from working properly. The vacuum
pump is fine, pulling 20" Hg. The circuit that appears to be leaking
the most is the locking/interlocking line (my guess) to the RHS doors.
These circuits are "fed" via a vacumm reducer that drops the vacuum
from 20" to about 15". The reducer has two "outlets". One outlet
goes to a yellow/grey_striped line, while the other outlet goes to
another yellow/???_striped line (i cannot see the colour of the stripe
from the engine compartment). This is the line that leaks a lot. I
only get about 5" of vacuum when that line is connected. It causes
failure of the engine shutdown actuator. So, for now i have
disconnected the locking/interlocking lines, and plugged the outlet in
the tee to maintain vacuum in the engine shutdown circuit. All three
door plungers are in the locked position so that we can use the car.
Does anyone have the trouble shooting guide for the vacuum system of
this car, and a a full schematic of all the lines, and vacuum tanks.
It would be of great help to locate the trouble spot, and make a
repair. At the moment i have the RHS front door cover removed. I had
to repair the inside door handle, and tighten a few bolts, plus inpect
and replace the plastic foil.
If you have schematics and want to send them to me, please use <con
underline trx at shaw dot ca>
Regards / John