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In order to ensure safety of the trailer transportation of the tractor and achieve the aim
of prompt stop of the tractor and trailer, air brake system is mounted on the tractor. The
system is made up of air compressor (1), receiver (5), brake valve (4), air pressure gauge and
pipes (Fig.4-23).
1) Working process of air brake device of trailer
Air brake trailer is braked through the compressed air driving the brake hung on the
trailer wheels. Firstly the compressed air is conveyed to receiver from air compressor through
pipes, then is conveyed to the brake air chamber of the trailer wheels through air-bleed hole
(hole B in Fig.4-24) of the brake valve. When stepping on the brake pedal, through the
connecting rod (8 in Fig.4-23) driving the pull arm 10 of brake valve (Fig.4-24) to rotate
around axle pin 13 to make adjusting bolt 12 press down brake pull rod 9, compress balance
spring 7, push core rod 5, compress return spring 4, push valve seat assembly 3 aside
(compress valve seat spring 2), open high pressure air passage, and at this moment, the
compressed air of receiver, from hole A to valve seat hole, then to mouth of hole B and
continuously respectively enter the left and right brake air chambers of trailer wheels
through air-bleed pipe (7 in Fig.4-23) of brake valve and three-way pipe connector and push
the brake tappets of left and right brakes, and thus achieve brake of the trailer.
After completing brake, loosen foot brake pedal, the brake adjusting bolt will return to
the initial position, and the brake tappets and core rod assembly will also return to their
initial position under the effort of compressed return spring; then the valve seat assembly 3
will move right to contact the valve mouth on left housing 6 under the effort of compressed
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valve seat spring, and reseal the passage between receive and the left and right brake air
chamber of the trailer. At this moment the waste gas (compressed air) in left and right air
chamber will go into the air through pipes, hole B of brake valve, inner hole of core rod and
inner hole C of tappets.(Fig.4-24).
2) Use and adjustment of air brake device of trailer
①
During working of air compressor, if the air pressure is too low, seal performance of
exhaust valve should be checked, and cleaned or ground if necessary. If the air compressor
has worked for 24 hours, and the oil gathered in the receiver is more than 15-20ml, the wear
condition of the piston rings of air compressor should be checked, and it should be replaced if
necessary. The air compressor should be checked or be filled with oil after every ten hours'
work.
②
Use and maintenance of brake valve
During using if the air pressure of receiver drops too fast, and all the pipe connectors are
confirmed to have no air leak, then screw out the valve cover connector 1 (Fig.4-24), clean the
gathered dust on the surface of the rubber of valve seat assembly 3, and slightly grind the
compressed prints on fine abrasive cloth if necessary. Generally after 1000 hours' work of the
valve, should dismantle and clean all the parts, grind the valve seat, adjust the maximum
pressure of brake, and check the seal performance after assembling.
③
Adjustment of brake pressure
When the brake pedals are stepped into the lowest place, the maximum pressure of the
air entered into the brake air chambers of trailer should be 0.45-0.5MPa. During adjustment,
connect an air pressure gauge in the pipes which pass through brake air chamber, rotate the
adjusting bolt 12 to contact tappet 9 according to Fig.4-24, then step on the pedals again to
the lowest position, if the numerical value on the air pressure gauge is lower than 0.45Mpa,
then use nut to lock the limiting bolt tightly.
④
Adjustment of brake time
The brake time of trailer should be basically synchronous with the brake time of the
tractor, otherwise it should be readjusted; adjust connecting rod 8 (Fig.4-23) to add its length,
the brake time of trailer will advance; adjust connecting rod 8 and reduce its length, the
brake time of trailer will extend. Generally the brake time of air brake trailer should be a bit
shorter than the brake time of
tractor.
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Ⅴ
. Main Troubles of Tractors and Trouble Shooting
1. Engine
1) Adjustment of dual stage clutch
2) Engine does not develop full power
Cause
Remedies
1.Weather cold
Pour hot water into the radiator or preheat the oil
before pouring it into crankcase
2.Fuel flow unsteady
Check and clean the fuel pipe line and filter
element
3.Air leaking into the fuel pipe line
Remove the air and tighten all fuel pipe
connections
4.Pump plunger and barrel ,
delivery valve and its seat ,nozzle
and its body sticking or damaged
Repair or replace them
5.Loss of compression pressure,
because of the inlet or exhaust
valve leaky ,no valve clearance ,
cylinder head gasket damaged ,
piston rings gummed up or worn
nut
Lap inlet or exhaust valve . Adjust the valve
clearance .Renew cyliner head gasket or piston
rings, if necessary.
6.Shortage of the battery electricity
Recharge or replace the battery
Cause
Remedies
1.Air filter or fuel filter choked
Clean it in light fuel or kerosene
2.Beginning of fuel delivery incorrect
Adjust according to the recommended procedure
3.The fuel containing water
Drain out the water deposit and change fuel
4.Nozzle needle sticking or holes
chocked
Repair or replace the nozzle unit
5.Inlet or exhaust valve leaking , or
valve clearance incorrect
Lap valve or adjust valve clearance
6.Main bearing or con-rod bearing
worn badly or seized up
Repair or replace them
7.Poor uniformity of single cylinder
output
Calibrate the fuel delivery of injection pump and
the injection pressure of injector
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3) Engine does not develop full power
Check if the engine can be cranked by hand . If
not , the cause may be as follows.
A.Crankshaft and bearing seized up Repair or change them
B.Piston sticking Repair or change piston cylinder liner
If the engine can be cranked freely , the causes may be as follows.
Cause
Remedies
1.Oil not enough or broken off
Check if oil gallery is stopped up and if the oil in
crankcase is enough
2.Oil diluted or aged
Check if the oil has been diluted by the leakage
fuel from fuel pump plunger unit and if the oil is
aged. If so ,settle the problem
3.Sudden oil pump failure or oil
filter stopped up or relief valve/by-
pass valve went wrong
Repair or change oil pump ,Clean or change the
element
Cause
Remedies
1.Engine overheated due to lack
of cooling water
Check regularly if the cooling water is enough
2.Cylinder overheated because of
water scale
Scour out the water jacket
3.Engine overloaded
Follow the regulations of operation specified
4.Low tension of
V-belt
Adjust the tension or change the belt
Cause
Remedies
1.Fuel consumed or fuel pipe crack
Replace fuel or change the pipe
2.Fuel containing air
Remove the air
3.Fuel filter or fuel pipe line
blocked up
Rinse the filter or the pipe
4.Plunger spring inside the injection
pump broken
Replace the spring with a new one
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