Porsche 928 Workshop Manual page 275

Differential, transaxle svstem
928
3. Attach plug to pressure warning switch
(plug on the pomp side remains discon-
nected at this point).
2389-039
4. Partially bleed the lock hydraulics as follows:
Wfih the ignition switched on, open the blee-
der valve on the lock solenoid valve. Attach
the electrical plug to the pump, As soon as
brake fluid emerges free from air bubbles.
pull off the electrical plug and close the blee-
der valve.
Next, charge the pressure reservoir com-
pletely.
To do this, attach the electrical
plug. As soon as the pump is heard to
switch
off, pull off the electrical plug and
reduce the pressure at the bleeder valve of
the lock solenoid valve. Slowly open the
bleeder valve and hold the bleed hose firmly.
Important: A pressure of up to 180 bar is
present in the system. Wear goggles and
protective gloves.
5. If necessary, connect pressure gauge -
special tool 9509 -to the pressure reservoir
and check the switching points of the pres-
sure warning switch and also for leakage in
the differential lock hydraulics.
The exact work procedures and nominal
values are stated on Pages D39-251 -
D39-256.
If necessary, top up the brake fluid level at in-
tervals so that the brake fluid reservoir is not
drained completely. The lock hydraulics must
be at zero pressure when connecting and re-
moving the pressure gauge.
6. Afler the testing and assembly work has
been completed, correct the brake-fluid le-
vel when the pressure reservoir is fully
charged.
D39 - 258
0
PSD diagnosis/Troubleshooting
Printed in Germany - XXXV. IN6