14
POWER STEERING
process. Due to the various types of
installation possibilities of our hydraulic
steering systems (inverted, vertical, horizontal
etc.) it can occur under certain circumstances
that for a short period of time, the steering
system cannot be bled in certain types of
vehicle and the air in the steering gearbox is
only removed very slowly. In such a case, we
recommend that the steering drop arm should
be removed so that the entire piston stroke
from stop to stop can be utilized in the steering
housing for the bleeding process.
In this way the air remaining in the cylinder is
reduced to a minimum.This is an insignificant
amount which is automatically absorbed by
the oil and separated during operation.
The steering system and pump should be filled
through the opening on the oil reservoir. For the
first filling and for oil changes it is recommended
to remove the cover of the container and fill with
hydraulic oil up to the edge of the container.
The engine should then be cranked briefly a
number of times with the starter in order to fill the
entire hydraulic systemwith oil. Since this causes
the oil level in the container to fall rapidly, the oil
must be continually topped up during this process
and under all circumstances the pump must be
prevented from taking in air.
3.2 Bleeding :
The engine can be started with the steering axle
jacked up when the steering system is filled with
oil so that the oil level no longer falls below the
upper marking on the oil dipstick when the engine
is briefly turned over.
Allow the engine to run for some time at low speed,
thus allowing most of the air to escape from the
cylinder. The oil level must be observed during
this process. The oil must be topped up
immediately if the level still sinks.
When the above instructions have been observed
the oil level in the oil container must not rise higher
than approximately 1 to 2 cm when the engine is
switched off, according to the size of the steering
system
Steering gear MO33 is with automatic bleeding
and do not have a bleeding screw. The steering
system automatically bleeds the remaining air in
I
II. Oil filling and air bleeding
Note :
There is a danger that dirt particles may enter
the steering oil circuit when filling the steering
unit with hydraulic oil. A high degree of
cleanliness must be observed for the first filling
and for all subsequent topping up operations
in order to prevent failure due to foreign bodies
in the system. For this reason, thoroughly clean
the oil reservoir and the area around it before
removing the oil reservoir cover or dip- stick so
that dirt does not get into the hydraulic oil.
1. Type of oil :
A suitable hydraulic oil must be used in order to
ensure perfect function of the steering unit and
the pump. The hydraulic oil also carries out the
lubrication of the steering gearbox and the pump;
therefore only one type of oil is necessary for the
entire unit.
The unit should be filled with ATF oils with a
viscosity of approximately 26 mm
2
/s (cst) at 50
0
C, a setting point below-35
0
C and with low
inclination to foam formation. Oils with a high
viscosity may lead to the situation that the under
pressure in the inlet line becomes too great thus
causing noises in the pump. (Approx. 2 ltrs.)
2. Oil quantity :
The hydraulic steering system is delivered from
the factory without being filled with oil. The oil
required for the complete system depends on
the length of pipes used in the system.
Type M033 0.3 Lts
3. Oil filling and air bleeding
3.1 Oil filling
Note :
Special care must be taken during the
procedure described as follows to ensure that
the oil reservoir is not allowed to run empty
since this would cause air bubbles in the
steering system. In addition to this, special
care must also be taken during oil filling and
air bleeding to ensure that the pump only turns
at the lowest possible speed (idling). If the
inlet flow is too great small air bubbles would
enter the pump and be split up into extremely
small air bubbles during its passage through
the pump; this situation may lead to foam
formation thus greatly extending the bleeding




