113
5.5.2.9 Coupling Heads (Fig.93) The heads have covers which protect the system from
dust and dirt. The feed head cover is painted red, the control head cover is painted yellow. To
connect the trailer brake system properly, couple the heads according to their color.
At first, the control head (yellow) is coupled, and then the feed head (red) is coupled.
Disconnect the pneumatic drive of the trailer in the reverse order.
Fig.93 – Coupling Head
5.5.2.10 Check Outlet Valves. The check outlet valve (Fig. 94), determines the output
parameters of the air pressure in the circuits with the help of the control pressure gauges.
In order to connect the valve, use the hoses with the coupling nut
М
16
х
1,5 and the pres-
sure gauges with the range 0-1000 kPa (0-10 kgf/cm2).
Fig. 94. Check Outlet Valve
1-body; 2-cap; 3-loop
5.5.3 The maintenance of the brakes pneumatic drive
5.5.3.1 While servicing the brake pneumatic drive of the truck the most important issue is
the system and its parts air-tightness monitoring. Pay a special attention to the tightness of the
pipes and flexible hoses connections as well as hose joints. Considerable air leakage is spotted by
ear, while small air leakage is detected with soap solution. The leakage is eliminated by tightening
the nuts with the following torque:
- for the pipes with the diameter of 10 mm – 21.6-27.5 N.m (2.2-2.8 kgf.m);
- for the pipes with the diameter of 14 mm – 49.0-60.8 N.m (5.0-6.2 kgf.m);
To avoid the failure of the connecting bosses on the brake mechanisms the tightening
torque of the connectors, angle joints and other fittings shall not exceed 30-50 N.m (3-5 kgf.m).
