Power Steering Pump: Testing and Inspection

Checking function of power-steering pump

Caution:
Make sure all parts are absolutely clean.
No dirt is allowed to enter the system.





Check all hose connections, pump and steering gear for leaks.
Detach pressure line from pump and connect special tool 32 4 000, refer to Notes on use.
1 = Connection, pump
2 = Connection, steering gear





Checking vane pump:
1. Close valve (A).
2. Open valve (B).
3. Start engine.
4. Correct hydraulic fluid level in tank.
5. Heat hydraulic fluid to approx. 50°C by moving steering wheel at increased engine speed.
6. Close valve (B) for max. 10 seconds, read off pressure and compare with nominal pump pressure.

If nominal pump pressure is exceeded by more than 10% replace vane pump, refer to Service and Repair, Procedures.
If nominal pump pressure is undershot by more than 10% check V-belt tension. If V-belt tension is O.K. replace vane pump, refer to Service and Repair, Procedures.





Checking power steering:
1. Open valve (B).
2. Close valve (A).
3. Start engine.
4. Pull steering wheel against left lock with 100 N (force meter) for approx. 5 seconds and read off pressure.
5. Perform same step against right lock.

The steering gear must be replaced if the pressure is below the previously determined pump pressure.

Note:
After removing special tool, replace sealing rings of banjo bolts and install pressure line.

Tightening torque:
- Hydraulic line connections to vane pump and steering gear
- M10 Banjo bolt 12 Nm
- M14 Banjo bolt 35 Nm
- M16 Banjo bolt 40 Nm
- M18 Banjo bolt 45 Nm
- Cap screw 36 Nm

Bleed hydraulic system, Refer to Power Steering Bleeding.