JAC Trucks. Manual - part 122

Possible causes and characteristics of faults

Methods of check & elimination

渊4冤Gear shifting is hard

(a) Shifting lever is not adjusted properly
(b) Articulated joints and pins are abraded
(c) Control damages
(d) Bolts and nuts loose

(a) Adjust the control lever
(b) Replace
(c) Replace
(d) Check and tighten

渊3冤Transmission chatters

(a) Installing screws of transmission and engine loose
(b) Gears or bearings are abraded

(a) Tighten
(b) Replace

Possible causes and characteristics of faults

Methods of check & elimination

渊2冤Gears are hard to mesh

(a) Engine idling speed is too high
(b) Clutch meshing is not good
(c) Clutch disc adheres
(d) Sliding bush of clutch inflects
(e) Input or output bearing is abraded or damaged
(f) Guide bearing of engine crankshaft is abraded or

damaged

(g) Synchronizer cone and ring are damaged
(h) Control system looses or is not adjusted properly
(i) Shift fork is abraded
(j) Control lever is not lubricated well
(k) Lubricant is insufficient or the viscidity degree is too

low

(a) Adjust idling speed
(b) Adjust clutch
(c) Repair or replace
(d) Replace
(e) Replace bearing
(f) Replace bearing

(g) Replace
(h) Tighten or adjust
(i) Replace
(j) Lubricate
(k) Add or replace lubricant

HFC1045

series trucks

Possible causes and characteristics of faults

Methods of check & elimination

渊1冤Rear axle makes abnormal noise

(a) Pinion bearing is abraded or damaged
(b) Side bearing of the differential is abraded or

damaged

(c) Pinion looses
(d) Differential gear looses
(e) Gear rings and pinions are abraded
(f) Thrust washer damages
(g) Differential cross shaft damages
(h) Gear rings and pinions are abraded
(i) Side bearing of the differential and pinion are abraded

or damaged

(j) Tightening bolt of the gear ring looses.
(k) Gear ring and pinion teeth do not contact well
(l) Pinion spline damages
(m) Shaft spline of rear axle damages
(n) Wheel hub bearing looses

(a)Replace bearing
(b) Replace bearing

(c) Adjust pre-tightening degree of bearing
(d) Adjust pre-tightening degree of bearing
(e) Adjust gear clearance
(f) Replace
(g) Replace
(h) Replace
(i) Replace

(j) Tighten
(k) Replace or adjust
(l) Replace
(m) Replace
(n) Replace

5.Faults of rear axle and elimination

Possible causes and characteristics of faults

Methods of check & elimination

渊3冤Rear axle heats

(a)oil seal gasket damages, oil outlet bolt looses, ventila鄄

tion hole is jammed, which causes that the lubricant is in鄄
sufficient

(b) Lubricant quality is bad
(c)Driving & driven gears as well as bearing are

adjusted too tightly

(a) Readjust after filling lubricants

(b) Replace lubricant in time according to season changing
(c) Readjust

(o) Wheel hub bearing is abraded
(p) Tightening bolts of gearbox loose
(q) Oil is insufficient
(r) Oil quality is not good

(o) Adjust pre-tightening degree of bearing
(p) Tighten
(q) Fuel
(r) Replace

渊2冤oil seal of semi-shaft leaks oil

(a) Ventilation hole or rear axle is jammed
(b) Lubricant quality is bad
(c) Driving & driven gears as well as bearing are

adjusted too tightly

(a) Readjust after filling lubricant
(b) Replace lubricant in time according to season changing
(c)Readjust

HFC1045

series trucks

Possible causes and characteristics of faults

Methods of check & elimination

渊1冤it爷s hard to turn or steering wheel cannot return smoothly

(a) Steering wheel shaft, sliding shaft or steering wheel

column deforms

(b) Universal joints loose or get stuck
(c) Bearing of steering wheel column does not rotate well
(d) Steering transmission shaft is not lubricated sufficiently
(e) Tyre pressure is too low

(a) Replace parts

(b) Replace universal joints
(c) Replace parts
(d) Add lubricant
(e) Inflate properly

渊2冤Steering wheel vibrates, steering operation is not sta鄄
ble

(a) Transmission shaft of the steering system looses
(b) Front wheel lose balance
(c) Tire shimmy is too great
(d) Disc grinding wheel damages
(e) Steering transmission shaft is abraded severely or the

clearance is too large

(a) Tighten properly
(b) Balance the wheel
(c) Correct shimmy
(d) Replace
(e) Replace parts

6. Faults of steering mechanism and elimination

Possible causes and characteristics of faults

Methods of check & elimination

渊3冤Front wheel deviates

(a) One of front wheel brakes sticks or shock absorber at

one side is invalid.

(b) Air pressure of one of the front tires is too low
(c) Reeds of leaf spring are misplaced or rupture
(d) Disc grinding wheel damages
(e) Toe-in of the front wheel is improper

(a) Adjust brake clearance or replace shock absorber

(b) Charge enough air
(c) Check front spring assembly
(d) Correct or replace
(e) Readjust

渊4冤Power steering pump leaks oil

(a) Oil seal or O-ring damages
(b) Lock nut or oil outlet plug of the oil seal damages

(a) Replace
(b) Repair

渊5冤Steering is heavy

(a) Steering gear fails
(b) Steering gear fails

bearing is improper

(a) Replace plug components
(b) Measure output pressure of the pump, replace the

gear if necessary

HFC1045

series trucks

Possible causes and characteristics of faults

Methods of check & elimination

(a) Clearance between shoe slice and drum of the parking

brake is too large

(b) There is oil dirt on brake drum and shoe slice
(c) Friction disc is over worn
(d) Parking brake cable is not adjusted and comes off;
clip spring is not installed

(a) Both upper and lower clearance should be adjusted

to 0.65mm

(b) Clean
(c) Replace
(d) Adjust, weld the joints properly, install clip spring

7.Parking brake is ineffective and relative elimination

8.Fault of service brake and elimination

Possible causes and characteristics of faults

Methods of check & elimination

渊2冤Brake efficiency is not good

(a) Air pressure is insufficient
(b) Free stroke of pedal is too long
(c) Clearance between brake drum and shoe slice is too

large

(a) Check or replace air pump, check the pipeline for leak
(b) Adjust to 8-12mm
(c) Adjust

渊1冤Service brake is ineffective

(a) Brake hose or pipeline ruptures
(b) Master cylinder valve of the brake is invalid

(a) Repair or replace
(b) Check & repair or replace

HFC1045

series trucks

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