57
Any kind of the air reservoir repair is not permitted
Drain water from the air reservoir every 10 hours of operation or daily by pushing drain valve at
bottom of the reservoir.
Pressure regulating valve with safety valve
The pressure is compressed to the air container through the valve. The valve reduces the air pressure
maintained by the compressor to p
e
=0,8
±0,02
and Δp
e
=0,06
±00,4
MPa. The pressure regulating valve is
fitted with a tyre inflating valve and a safety valve which limits the maximum air pressure inside the
tractor pneumatic installation for braking the trailers (Fig. 5.13.4).
To inflate the tractor or trailer tyres, first reduce pressure in air system to 0,3 MPa (stop the engine
and drop air by the drain valve from the air reservoir) and connect the valve to the wheel inflation
valve with a rubber hose and with the engine running, inflate tyres to the prescribed pressure. The
valve is located on front lower edge of cab on tractor R.H. side (beside main earth switch).
No periodical servicing of this pressure regulating valve is necessary. Inspections and adjustments
can be made by a specialized service only.
Equalizing device
The equalizing device (which is at the same time the foot of R.H. side brake pedal) is used for leveling
the R.H. and L.H. pedal plates of the main brake (two pedals latched together).
Neither servicing nor adjustment of this device is necessary.
Trailer braking control valve
The foot brake valve (which is at the same time the foot of R.H. side pedal) is used to operate the
trailer brakes.
The trailer braking force is proportional to the pressure exerted on the brake pedal. Pressing on the
pedal causes the compressed air supply to the trailer to be progressively cut off and thus braking
the trailer. The air escapes through the valve.
Adjust the foot brake valve every 250 hours of operation by setting correct length of the valve
linkages.
The adjustment of the foot brake valve must always follow the adjustment of tractor brakes.
Parking brake valve
The valve is connected by pull rod with the parking brake lever. When engaging the parking brake,
the hand brake valve is operated (a hissing sound of the air escaping from the valve should be
heard). If the hand brake valve is out of operation (no hissing sound) shorten the pull rod which
connects the valve with the parking brake lever.
Coupling valve
The pneumatic system of the tractor and trailer can be coupled by means of this valve which is
standard design.
Connecting the trailer and tractor air braking system
As a standard, tractor is fitted with single line air braking system with one (white) air braking
coupling.
In option the tractor is fitted with double line air braking system with three couplings (Fig. 5.13.3).:
white
– to couple single line trailer air braking system,
red
– to supply triple line trailer air braking system,
yellow
– to control triple line trailer air braking system.
All couplings are fitted with automatic valves to cut off tractor air braking system after disconnected
of trailer coupling. The couplings are accordant to ISO standard.
To couple the trailer and tractor air braking system, equalize air pressure in tractor system with
ambient pressure (by engaging the parking brake) and after connecting hose couplers release the
parking brake. Tractor and trailer braking should be at the same time. Couple also trailer electrical
system to the tractor seven pin socket (2 - Fig. 5.13.3).
