MAINTENANCE AND TYPES OF OILS
Thoroughly clean the oil tank and its immediate vicinity before
removing the cap, in order to prevent dirt entering the hydraulic oil.
When cleaning the vehicle with steam-cleaning equipment, do not
direct the jet of steam directly against exposed seals of units
belonging to the steering system. Water penetrating protective caps,
shaft seals or the seals of universal joints may cause corrosion
In the sections below, the intervals for inspections of ZF hydraulic
steering gear are stated in kilometers driven and in service hours.
The kilometers-driven data are applicable to road-going vehicles, the
service-hour data apply to off-road vehicles. The quantity of fuel
consumed will serve as a reference value for the intervals for
vehicles equipped with neither an odometer nor a service-hour
In the course of general service jobs for the respective vehicle all the screw connections and lines
of the power steering gear, pumps, engine and drive-dependent valves and power cylinders are
checked for leaks. The piston rod of the power cylinder may be coated with a thin oil film, but no
drops should show up.
If the steering system is subsequently installed, the installing workshop should make this checkup
after driving 1,000 km or after 25 hours of operation.
The power steering gear is delivered from the factory without oil. The required oil quantity for the
steering gear amounts to approx. 1.2. dm3.
Oil change is recommended when the steering gear or pump or both are repaired or exchanged. In
such a case, the filters in the oil reservoir (tank) should also be exchanged and the lines should be
When pulling out the contaminated filter cartridge, the lower opening must be kept closed
immediately after lifting the cartridge from filter carrier to make sure that the contaminated oil in the
filter cartridge flows back into the tank and will then again enter the oil circuit.
Drain the oil as follows:
Do not run engine for more than ten seconds (at idle and with oil tank
sucked dry), otherwise the pump will seize. Mixing of oil types should be
Jack up steering axles as well as the associated drive axle for the drive-dependent pump drive.
Unscrew oil drain plug below on steering case and loosen hose connections on power cylinders.
Engage a gear step and start engine for a short moment until oil has been drained out of the tank.
Keep turning steering wheel from lock to lock. After stopping the engine, turn steering once again
from lock to lock until no more oil is flowing out. Fasten line connections again to power cylinder.
Screw in oil drain plug. For tightening torque, refer to Technical Data.