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I.1.3.1.1 Wheel brake mechanism (shown in Fig. I.9) is drum-type with the internal
brake shoes 9 replaceable for each wheel. Each brake unit has a hydraulic cylinder. The brake
shoes are mounted on the bearing axis 12.
I.1.3.1.2 Simplified adjustment of service brakes
Brake unit is adjusted upon the linings wear by reducing the clearance between the lining
and the drum using adjusting cam gears 8.
1-wheel cylinder; 2–cylinder piston; 3–ring; 4–sleeve; 5–spring; 6–protective cover; 7–brake support; 8–
adjusting cam gear; 9–brake shoe; 10-brake shoe lining; 11–wrench; 12–brake shoe pin; I–clearance de-
crease; II–clearance increase
Fig. I.9 - Service brake unit with the single-lane cylinder
The brake adjusting order:
- using the wrench of 22 mm turn the adjusting cam gears against the stop. Turn the right
(on the side of the support) clockwise, and the left one anticlockwise;
- loosen the cams by turning them backwards by 30° which corresponds to the cam axis
end half turn.
Having followed the above-mentioned steps for all wheels; check whether the brake
drums run hot during driving.
I.1.3.1.3 Speed sensor. Brake mechanisms of the front and of the rear wheels has induc-
tive sensors 2 shown in Fig. I
.10
. In order to avoid damaging of the inductive sensor 2 it shall be
recessed (from the center) by the brake drum before mounting. Then make it go till it thrusts
against the impulse ring without excessive effort.
Inductive sensor 2 consists of a permanent magnet with a round rod and a coil. The rota-
tional movement of the toothed impulse ring induces voltage pulses in the sensor’s; pulse’s fre-
quency is proportional to the wheel rotation speed. The sensor is mounted in a special bushing
