Porsche 928 Workshop Manual page 979

928
Differential, Transaxle System
39
Bleeding hydraulics of Porsche controlled slip differential (PSD)
. Remove rear Ml inner fender
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Connect bleeding device to PSD hydraulic reservoir
. Disconnect vent line
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Build up bleed pressure (approx. 1.5 2.0 bar)
1. Bleeding the pressure reservoir
To charge the pressure reservoir, the
ignition must be switched on.
When the pressure reservoir has been charged, the pump cuts out; reservoir pressure is then ap-
prox. 180 bar.
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Connecting the bleed cylinder.
. Switch off the ignition.
. Carefully open the bleed connection and allow the pressure level to drop gradually.
While this is being done, the
ignition must remain switched off,
to ensure that pressure is
completely reduced and air expelled from the reservoir.
. Repeat this procedure several times, making sure that
the ignition is switched on or off a1 the
appropriate stages in the procedure.
2. Bleeding the valve block and the locking line to
the lock slave cylinder
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Connect the 9288 system tester
Switch the ignition "ON"
Connect the bleed cylinder to the bleed screw on the slave cylinder
Open the bleed screw on the slave cylinder
Select "Start PSD Bleeding" and actuate repeatedly until no further air emerges
The bleeding device must remain switched on, because the reservoir volume is used up rapidly,
After this, close the bleed screw on the slave cylinder
Select "Stop Bleeding" and "Start Pressure Reduction" at the system tester
Switch off the bleeding device and disconnect it
Screw on the reservoir cover
Open the vent line at the reservoir again
Check level in reservoir. The liquid must be approx. 1 cm above the step in the reservoir body
(with the pressure reservoir charged)
a
Bleeding hydraulics of Porsche controlled slip differential (PSD)
39 - 206i
Printed in Germany - XXV, 1990