Belarus 921.6 Operator's Manual page 123

The pneumatic actuator is equipped with the valve-type coupling heads 11, 12, 13
(Figure 4.7.3). The coupling head valves prevent air escaping when the pneumatic actua-
tor is used without the trailer (for example during tyres inflation) and in case of emergency
trailer decoupling. When the trailer brake pipelines are connected to the tractor connecting
pipeline, the coupling head valves are opening and provide for compressed air passage
from the tractor pneumatic actuator to the trailer. Meanwhile, the pneumatic pipelines shall
be connected when there is no pressure in the tractor cylinder 3.
While connecting the trailer with single-line pneumatic actuator, connect the trailer
coupling head to the tractor pneumatic actuator coupling head 12 (with black cover).
While connecting the trailer with two-line pneumatic actuator, connect the trailer
coupling head with red cover to the tractor pneumatic actuator coupling head 11 (with red
cover) and connect the coupling head with yellow cover to the tractor pneumatic actuator
coupling head 13 (with yellow cover).
ATTENTION:APPLY THE PARKING BRAKE PRIOR TO CONNECTING OR DIS-
CONNECTING THE PNEUMATIC PIPELINES OF THE TRACTOR AND TRAILER! THE
TRACTOR AND TRAILER PNEUMATIC PIPELINES SHALL BE CONNECTED WHEN
THERE IS NO PRESSURE IN THE TRACTOR PNEUMATIC SYSTEM!
1 – pressure regulator; 2 – air take-off valve; 3 – cylinder; 4 – condensate drain valve;
5 – air pressure indicator; 6 – emergency air pressure indicator light; 7 – air pressure sen-
sor; 8 – emergency air pressure sensor; 9 - two-line brake valve; 10 – feed pipeline; 11 -
feed pipeline coupling head (with red cover); 12 – connecting pipeline coupling head (with
black cover); 13 - control pipeline coupling head (with yellow cover); 14 – control pipeline;
15 – connecting pipeline; 16 – single-line brake valve; 17 – compressor; 18 - pipeline from
the diesel engine intake manifold.
Figure 4.7.3 – Diagram of the combined pneumatic actuator of the trailer brakes.
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921.6-0000010 OM