Hydraulic Drive Of Trailer Brakes - Belarus 1523.5 Operator's Manual

1523.5-0000010 OM
Direct brake control is carried out due to pressure fall in the connecting line from 5 to 0
MPa while tractor braking. In this case, compressed air supply to the trailer pneumatic sys-
tem stops.
Automatic brake control (automatic braking) is carried out in case of hitch breakage or
trailer disconnection due to pressure fall in the trailer connecting line.
While coupling of the trailer with double-wire pneumatic drive, connecting heads of the
trailer are attached to connecting heads 7 (with a red cap) and 9 (with a yellow cap), that is
to feed line 6 and control line 10. In this case, compressed air constantly flows to the trailer
through feed line 6. When pressing the brake pedal or engaging the parking brake, com-
pressed air is supplied to the trailer through brake valve 3 and control line 10. The air dis-
tributor comes into action on the trailer supplying compressed air from the trailer tank into
brake chambers and the trailer brakes.
Direct brake control is carried out due to pressure in the control line 10 set from 0,65 to 0,8
MPa while tractor braking. In this case, feed line 6 stays under pressure and compressed
air supply to the pneumatic system is kept.
Automatic brake control (automatic braking) is carried out in case of hitch breakage or
trailer disconnection due to pressure fall in the trailer feed line.
Connecting heads of valve type 7, 8, 9 are mounted at the end of connecting lines. The
valves of connecting lines prevent compressed air from flowing out when using the drive
without a trailer (for example, while tire inflation). While connecting the trailer brake lines
with the tractor brake lines 5, 6,10, the valves of connecting heads open providing the
compressed air ingress from the tractor hydraulic drive to the trailer. In this case, it is re-
quired to connect the tractor and trailer pneumatic lines when there is no pressure in tank
12 of the tractor.
ATTENTION: BEFORE CONNECTING OR DISCONNECTING THE TRACTOR OR
TRAILER PNEUMATIC LINES, ENGAGE THE PARKING BRAKE! CONNECTION OF
TRACTOR AND TRAILER PNEUMATIC LINES SHALL BE CARRIED OUT WHEN
THERE IS NO PRESSURE IN THE TRACTOR PNEUMATIC SYSTEM!

4.7.3 Hydraulic drive of trailer brakes

Tractors "BELARUS-1523.5" can be equipped with the hydraulic drive of trailer brakes
against order.
The hydraulic drive of trailer brakes is interlocked with tractor operating brakes control and
provides actuation of wheel brakes of trailer or semi-trailer, equipped with the system of
the hydraulic drive of trailer brakes. The hydraulic connecting line is fed from the HLL
pump that provides pressure between 10 ...15 MPa and is made as single-wire brake sys-
tem. The connection of the hydraulic drive corresponds to the standard ISO/5676 of 1983.
The hydraulic drive of trailer brakes is subsequently fed from the pump of the tractor hy-
draulic lift linkage with the help of high-pressure hoses 4 and 5 (figure 4.7.2). As brake
valve 2 comes into action, oil is supplied to the trailer (semi-trailer) brake system along line
9 through coupling 1. Brake valve 2 comes into action when brake liquid is supplied from
the operating brakes control system to brake valve 2 along lines 8 to distribution valve 7.
Brake liquid is supplied to brake valve 2 when both operating brake pedals are pressed at
the same time. If only one brake pedal is pressed, distribution valve 7 does not come into
action and accordingly, brake liquid is not supplied to brake valve 2.
Coupling 1 prevents oil outlet when the hydraulic drive is used without the trailer. When
brake line of the trailer is connected with brake line of the tractor, the coupling provides oil
inlet to the trailer
ATTENTION: TRACTOR EQUIPPED WITH THE HYDRAULIC DRIVE OF TRAILER
BRAKES CAN NOT BE COUPLED WITH TRAILERS HAVING THE PNEUMATIC DRIVE
OF THE BRAKES!
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