Four-Wheel Parking Brake - Mercedes-Benz Unimog Operating Instructions Manual

Brakes
166
Parking brake
G
WARNING
If the parking brake lever is not in the fully
applied position, it automatically returns to
the released position. The vehicle could roll
away as a result. There is a risk of an accident.
Move the lever into the fully applied position
when parking the vehicle.
G
WARNING
The parking brake may not be sufficient to
ensure that the loaded vehicles does not roll
away on uphill and downhill gradients. There
is a risk of an accident.
In the test position, check whether the park-
ing brake will hold the loaded vehicle. If the
vehicle is not held, secure it using other meth-
ods, e.g. wheel chocks.
Secure the parked vehicle against rolling
away by applying the parking brake. The park-
ing brake actuates the spring-loaded parking
brake cylinder.
You can find further information about the
parking brake on the trailer in the manufac-
turer's operating instructions.
Applying the parking brake
X
Move parking brake lever : from released
position 1 to fully applied position 2 and
engage it.
The ! indicator lamp in the instrument
cluster lights up.
Trailer with EC brake system: when a trailer
is attached, the parking brake actuates the
trailer's service brake.
Vehicle with trailer: check the parking
brake when parking the vehicle
X
Apply the parking brake.
X
Press the top of parking brake lever :.
While doing so, move parking brake
lever : beyond fully applied position 2
into control position 3 and hold it.
During the test, the vehicle combination is
only held by the force exerted by the spring-
loaded brake of the tractor vehicle. The
trailer brake is released.
The vehicle must not move.
X
If the force exerted by the spring-loaded
brake cannot hold the vehicle combination,
secure the tractor vehicle and trailer using
chocks.
X
Move parking brake lever : from control
position 3 back to fully applied position
2 and engage it.
Releasing the parking brake
X
Pull parking brake lever : upwards from
fully applied position 2 and swing it up
into released position 1 as far as it will go.
The ! indicator lamp in the instrument
cluster goes out.
If the reservoir pressure in both brake cir-
cuits is above 8 bar, the parking brake
releases fully.
If the ! indicator lamp in the instrument
cluster does not go out, the reservoir pres-
sure in the spring-loaded brake circuit has
dropped below 5.5 bar and is too low.
To tow the vehicle, you can also release the
spring-loaded parking brake cylinder on the
parking brake manually (

Four-wheel parking brake

The four-wheel parking brake couples the ser-
vice and parking brake electropneumatically.
It is only active when the engine is running
Y page 335).