Power Steering Bleeding: Service and Repair
Filling and Bleeding Power Steering Tandem PumpTo determine power steering pump application, Application and ID
Capacities:
Model 124, 129, 201, 202 approx. 1.0 liter
Model 140 approx. 1.4 liter
1. Version (model 201 up to 09/84) When engine is cold (room temperature approx. 20°C) oil level 6-8 mm below marking (arrow). When oil is at operating temperature (approx. 80°C) correct oil level up to the embossed or cast-in marking (arrow).
2. Version 10/84 to 01/91 The reservoir is filled correctly when the oil (20-50°C) is between the min. and max. markings, 28-36 mm below the edge of the reservoir.
3. Version as of 02/91 When engine is cold (room temperature 20°C) oil level at the maximum marking of the oil level display (30°c) of the power steering/tandem pump (30).
4. Filling/Bleeding
Before starting the engine, fill with specified steering gear oil to approx. 10 mm below the upper edge of the reservoir.
Start engine. allow to run for approx. 1 s. Switch off engine and immediately replenish extracted oil. The power steering pump must NOT ingest any air. Turn steering several times anticlockwise and clockwise towards full lock so that the system can bleed itself. On vehicles with tandem pump (level control, ADS, ASD or 4MATIC) bleed the respective systems separately.
5. Oil Level Check
Correct oil level depending on the version.
6. Leak Testing
A power steering/tandem pump must only be replaced if oil leakage (pronounced formation of droplets) has been established and the oil level is below the minimum marking.
A slight oil film on the radial seal ring or on the housing joint face is due to the system.
a) Leakage at the Pipe Connections:
Retighten high pressure hose. If this is not successful, the connection nipple must be checked for damage. If necessary. replace high-pressure hose.
b) Formation of droplets on the underside of the power steering pump:
The cause of this is often an overfilled reservoir.
NOTE: Before the cover is screwed onto the reservoir. clean the sealing surface of the cover and its support surface on the reservoir.