JAC Trucks. Service manual — part 120

69

吁尧maintenance

(玉) Daily maintenance

(域) 1

st

class maintenance

(芋) 2

nd

class maintenance

(郁) Seasonal maintenance

(吁)Items to notice in breaking-in period

negative temperature coefficient and
its resistance decreases with the in鄄
crease of water temperature, which
change current going by it. Don爷t re鄄
place the sensor for one with positive
temperature coefficient, or the water
temperature gauge will not work cor鄄
rectly.
3. Oil pressure alarm device
Oil pressure alarm device is a switch
closed in usual time. It will be
opened when oil pressure reaches or
is over the lowest pressure, the cir鄄
cuit is disconnected and the indica鄄
tor goes out.

68

HFC1045

series trucks

71

70

After breaking-in period, daily main鄄
tenance should be done periodically
according to working condition and
technical requirements. Generally,
mileage of 1st class maintenance
should be 2000-2500km if the vehi鄄
cle runs on common roads. Mileage
of 2nd class maintenance should be
15000km.

Seasonal

maintenance

should be done when summer be鄄
gins or winter begins.

(玉) Daily maintenance

1. Check whether fuel, oil and cool鄄
ing water are sufficient before driving
and whether there is oil leak; exhaust
air in oil paths at different rotate
speeds. Check whether engine and
instruments work normally; check
working condition of steering mech鄄

anism, brake, tire, lights, horn, wiper
and towing devices; check whether
tools and accessories with vehicle
are prepared; check whether the
loading is proper and reliable.
2. Pay attention to working condition
of all instruments, engine and parts
of chassis in running; check whether
temperatures of wheel hub, brake,
transmission and rear axle are nor鄄
mal; check tightening condition of
propeller shaft, wheel hub, leaf
spring, steering system and braking
system; check whether the pressure
of tires is normal; check the wheel
buts for looseness.
3. After daily driving, clean inside
and outside of the vehicle body and
every part of the chassis; cut off the

power source, add fuel, lubricants
and cooling water, lubricate points
need lubricating, and cooling water
should be drained in winter if there
isn爷t any anti -freeze added to the
cooling water. Check and inflate the
tires according to specification.
Clean outside of the accumulator and
check whether it is installed fixedly.
The accumulator should be taken to
warm room in exceedingly cold
weather. Five items should be en鄄
sured sufficient (water, fuel, lubri鄄
cants, distilled water in accumulator,
tire pressure); four items should be
ensured not to leak (oil, water, air,
electricity)

(域) 1

st

class maintenance

1

st

class maintenance concentrates

on tightening, lubricating, besides
daily maintenance, the following
items should be done:
1. Check and clean air cleaner and
fuel filter
2. Check whether engine, transmis鄄
sion, rear axle, redirector, fuel injec鄄
tor and adjustor leak; check whether
oil or gear oil is sufficient and clean
vent holes.
3. Clean dirt and dust on outside and
poles of the accumulator and dredge
holes on the cover. Check specific
gravity of the electrolyte, liquor level
and tightening condition of the lead.
4. Clean begrimes on the generator
and carbon brush as well as com鄄

mutators; check condition of the
starter switch, lubricate generator
bearing. Check whether timing lines
of the fuel injector align and check
whether relevant control valves and
cables are agile.
5. Check fuel hose, brake hose, vac鄄
uum hose, pipe joints of cooling wa鄄
ter, radiator and water pump for
looseness and leak, and tighten
them.
6. Check and adjust free strokes of
all pedals and check whether control
mechanisms are tightened and work
normally; check and adjust clear鄄
ances between clutch friction disc,
parking brake shoe slice and service
brake shoe slice, and fill brake fluid.
7. Check and tighten the redirector,

adjust windage of the steering wheel;
adjust degree of tightness of front
wheel toe-in and wheel hub bearing.
Check tightening condition of driving
gear nuts of the rear axle.
8. Check condition and tightening
condition of the leaf spring, lubricate
leaf spring pins; check and tighten
engine supporting, center bearing of
transmission shaft and connection
parts of universal joints.
9援 Check tire surface, air pressure
and tightening condition of the tire
(including spare tire)
10. Check working condition of horn,
turning lights, brake lights, lighting
devices and electric apparatus.
11. Lubricate points to lubricate of
water pump, transmission shaft, ball

HFC1045

series trucks

pins of transverse and vertical steer鄄
ing pull rods, release bearing of
clutch, parking brake and door
hinges.

(芋) 2nd class maintenance

2

nd

class maintenance concentrates

on inspection, adjustment, lubrica鄄
tion; besides items in 1

st

class main鄄

tenance, the following items should
be done:
1. Check air pressure in the cylinder,
remove carbon deposits in the com鄄
bustion chamber, and measure
abrading degree of the cylinder.
2. Check seal condition of the valve,
adjust valve clearance, do adjusting
and rubbing if necessary, and then
readjust.
3. Replace engine oil, fine mesh filter

element and seal rings, and wash lu鄄
brication system of engine.
4. Check and adjust angle of ad鄄
vance of the diesel engine; check
injection pressure and atomization
condition of the fuel injector; wash
the oil tank.
5. Check whether the thermostat
works normally; check drip condition
of the draining hole of the water
pump.
6. Check whether vent -pipe of the
crankcase is complete and fastened.
7. Check working condition of the
generator and starter; especially
check whether electric brush and
commutators abrade.
8. Check and adjust separating
clearance of the clutch

9. Readjust clearance between fric鄄
tion disc of service brake and the
brake as well as clearance between
friction disc of parking brake and the
brake.
10. Tighten bearing cover of trans鄄
mission; check whether shifting of
transmission is normal. Check and
lubricate odometer hose.
11. Clean and replace gear oil for
transmission, rear axle and steering
gear.
12. Check the frame for cracks,
check the bolts for looseness, check
whether parts of cab and carriage
are complete, check whether the de鄄
vices are fixing.
13. Jack up the vehicle to make front
and rear wheel off ground; start the

engine, after the engine is heated,
accelerate in interval and listen
whether there is any abnormal noise
in the engine, watch whether there is
any abnormal noise in the transmis鄄
sion system, shaking and swaying of
the wheels, and other parts.

(郁)Seasonal maintenance

In order to make some parts meet
the requirements of climate change
in aspects of technique and working
requirement, seasonal maintenance
should be added in summer and
winter.
At the beginning of summer:
1. Clean cooling system up and re鄄
move scale in it.
2. Use lubricant for summer.
3. Fueling with #0 light diesel oil

specified in GB252.
4. Clean up the battery and adjust
the specific gravity of electrolyte.
At the beginning of winter:
1. Clean up the accumulator and ad鄄
just the specific gravity of electrolyte,
and then remove the accumulator
and charge it.
2. Install cold -proof devices; install
antiskid devices if necessary.
3. Fueling with #10 light diesel oil
specified in GB252.

( 吁 ) Items to notice in
breaking-in period

Proper breaking -in of new vehicle
has a great influence on prolonging
vehicle lifespan and improving relia鄄
bility and economy of vehicle.

Mileage of breaking -in is 2000 -
2500km, and the following specifica鄄
tions should be executed during
breaking-in period.

1. Before breaking-in period

1) Wash the vehicle with water, and
check whether all bolts and nuts are
tightened.
2) Check whether there is enough
water in the radiator, and whether
quantity of lubricants in engine,
transmission, rear axle, and steering
gear as well as liquid levels in bat鄄
tery and oil reservoir conform to
specification; Check pipeline joints
for leak.
3) Check whether start system尧driv鄄
ing system, and steering system
work normally.

HFC1045

series trucks

72

73

4) Check whether electrical equip鄄
ments and lamp instruments work
normally, and check whether air
pressure of the air brake is normal.
5) Check whether gears of the trans鄄
mission are right, whether the control
parts are normal, whether indication
of the gear position transmission is
right, and whether the shifting is
smooth and free.
6) Check whether air pressures of
tires are proper.
7) Check whether tools and acces鄄
sories are prepared.

2. During breaking-in period

1) The new truck should run on
smooth road, and don爷t make it load
more than 50% of its rated load be鄄
fore it travels 800km and don爷t load

more than 75% before 1500km, or it
will shorten truck爷s life and bring
driver danger.
2) Don爷t run faster than the following
speed.

First gear

7km/h

Second gear

14km/h

Third gear

26km/h

Forth gear

40km/h

Fifth gear

56km/h

3) At the beginning, check tempera鄄
tures of the rear axle, transmission
case, drive shaft, and brake drum.
Give ear to the sound of chassis
when driving and stop to inspect if
abnormal noise is heard, then shoot
trouble before driving again.
4) Pay special attention to tempera鄄
ture of the cooling water and oil

pressure. Do not drive the vehicle as
temperature of the cooling water is
under 60益 ; do not drive at a high
speed when the temperature is be鄄
low the normal temperature (among
80益 to 90益).
5) Check whether the engine cylinder
cover, wheel nuts, car body, and the
U -bolt of leaf spring are tightened
regularly. Check whether the steering
system, brake system, and clutch
can operate normally. Inspect free
stoke of steering wheel; inspect op鄄
erating stroke and free stroke of the
brake pedal and clutch pedal.
Notes: Cylinder cover bolts should be
tightened twice as the cylinder is
cool according to diagonal sequence
from the center to both sides and

crossed sequence.
6) Replace engine oil after 2500km
running (do it when engine is hot),
then replace again in second -class
maintenance.

3. After breaking-in periods

1) Replace engine oil, oil filter ele鄄
ment, gear oil for transmission and
rear axle, lubricant for steering gear
and lubricating grease for wheel rim
bearings
2) Check tightening condition of out鄄
er bolts and nuts of the whole vehicle
according to specified tightening
torque.
3) Lubricating grease should be filled
to every lubricating point
4) Maintain the vehicle according to
1st class maintenance

HFC1045

series trucks

74

75