2. Normal Troubles of Engine
Description of trouble: engine cann’t accelerate.
Diagnosis of trouble: engine only can revolve at one fixed speed however operator controlles the accelerator.
No. Judgment & Checking Solution of Trouble
1. Loosening between the lever and shaft of throttle Tightening the lever and shaft of throttle
2. Blockade of the fuel filter Cleaning the fuel filter
3. Blockade of the air filter Cleaning the air filter
4. Flow of fuel is much too small. Adjusting the flow of fuel
5. Blockade of the screen of magnetic filter Cleaning the magnetic filter
6. Damage of the governor Replacing the governor
3. Normal Troubles of Engine
Description of trouble: temperature of engine is too high.
Diagnosis of trouble: temperature of engine is higher than normal working temperature for a long time.
No. Judgment & Checking Solution of Trouble
1 Factors of non-cooling system
(1) mechanical fault caused by the bad lubrication
(2) incorrect start-up timing
(3) mixture gas is too thick or weak
(4) there is too much accumulated carbon in combustion chamber
2 Factors of cooling system
(1) coolant is not enough or choosing incorrect coolant.
(2) too much furring in the radiator or engine block
(3) failure of sensor
(4) damage of thermostat
(5) low pressure of water punp or radiator
(6) sliding of fan belt
4. Normal Troubles of Engine
3 Outer factors
(1) outer temperature is too high
(2) working in the highland
(3) climbing the slope continously
4 Using factors
(1) running at a low speed for a long time
(2) over-charged working at a low speed
(3) continous brake during the working
5. Normal Troubles of Engine
Description of trouble: bulldozer cann’t move when engine body is cool.
Diagnosis of trouble: bulldozer cann’t move immediately after starting up the engine when it is cool and the
control lever is connected into one transmission gear.
Judgment & Checking:
1. air leakage occurs in the hydraulic systen
2. fuel-feeding is shortage as the relevant hose is aging.
3. blockade of filter
4. oil or fuel is damaged
5. leakage of transmission pump or transmission valve
6. Normal Troubles of Engine
Description of trouble: bulldozer cann’t move when engine body is hot.
Diagnosis of trouble: bulldozer cann’t move or it is powerless when engine power is unchanged.
Judgment & Checking:
Usually this trouble is caused by the failure of torque converter, gear box, steering clutch or brake system.
Please confirm the failure points by watching the revolution of universal joint and transmission gear.
7. Normal Troubles of Engine
Description of trouble: exhaust gas is blue.
Judgement & Checking: oil is too much or piston rings wear out.
Solution of trouble: draining redundant oil or replacing the piston rings
Description of trouble: exhaust gas is white.
Judgement & Checking: fuel is not qualified or water goes into combustion chamber
Solution of trouble: using qualified fuel and draining the water in combustion chamber
8. Normal Troubles of Engine
Description of trouble: engine is powerless
Judgement & Checking:
(1) blockade of air filter, air intake system or fuel filter
(2) shortage of fuel feeding caused by damaged PT pump
(3) wear-out of cylinder liner, piston or piston rings
Solution of trouble:
(1) replacing the relevant filters and repairing air intake system
(2) adjusting the PT pump
(3) replacing cylinder liner, piston and piston rings
9. Normal Troubles of Engine
Description of trouble: early wear-out of engine
Diagnosis of trouble: oil is burnt in oil pan, and white smoke exhausts from oil inlet position.
Judgement & Checking:
1. air filter is badly sealed, and dust pollutes the burning house
2. cylinder linner, piston & piston rings are damage because the above reason.
Solution of trouble:
1. cleaning and repairing air intake system
2. replacing the damaged cylinder linner, piston and piston rings
10. Normal Troubles of Engine
Description of trouble: fuel is mixed into oil in the oil pan of engine .
Diagnosis of trouble: oil level rises and layer appears
Judgement & Checking:
(1) damage of seal ring of injector
(2) damage of copper liner in the cylinder cover
(3) failure of injector
(4) checking whether exhaust valves are opened
Solution of trouble: replacing the damaged parts
11. Normal Troubles of Engine
Description of trouble: water is mixed into oil in the oil pan of engine.
Diagnosis of trouble: color of oil becomes white
Judgement & Checking:
(1) checking oil cooler
(2) checking cylinder gasket
(3) loosening of water plug or whether there some crackles in water dypass of cylinder cover
(4) water leakage of cylinder liner & water seal
12. Normal Troubles of Engine
Description of trouble: engine cann’t be started.
Diagnosis of trouble: engine cann’t be started when power is on.
Judgement & Checking:
(1) damage of starting switch
(2) fuse is melted.
(3) voltage is low
(4) damage of starting relay
(5) damage of stating motor
(6) blockade of fuel & fuel filter
(7) damage of electromagnetic valve
13. Normal Troubles of Engine
Description of trouble: water pump is damaged.
Diagnosis of trouble: temperature of water rises rapidly.
Judgement & Checking:
(1) checking the belt of fan
(2) whether water is boiling in radiator (if water is not boiling, it states that water pump is damaged.)
Solution of trouble: replacing the water pump.
14. Normal Troubles of Engine
Description of trouble: PT pump is damaged.
Diagnosis of trouble: engine is powerless and it is no use to change fuel filter.
Judgement & Checking: openning joint of the pipe from PT pump to injector, stating the engine and
watching the spurting height of fuel. If it is lower than 5cm, it states that there is some faults with PT pump.
Solution of trouble: adjusting the PTpump.
15. Normal Troubles of Engine
Description of trouble: oil cooler is damaged.
Diagnosis of trouble: there is some oil in the radiator
Judgement & Checking:
(1) checking whether there is some water in the oil pan of engine. If water exists, it confirms that oil cooler of
engine is damaged.
(2) checking whether there is some water in the transmission case. If water exists, it confirms that
transmission oil cooler is damaged.
(3) special factors, such as crackle of cylinder cover, damage of water seal of cylinder liner.
Solution of trouble: replacing the relevant oil cooler ass’y
16. Normal Troubles of Engine
Description of trouble: turbocharger is damaged.
Diagnosis of trouble: engine is powerless and exhaust gas is black.
Judgement & Checking:
trying to operate the bulldozer after dismantling air filter. If the fault still cann’t be solved, please dismantle the
pipes of turbocharge and then failure point will be found by checking the rotation of turbocharger.
Solution of trouble: replacing the turbocharger
17. Normal Troubles of Engine
Description of trouble: oil presure of engine is lower than the normal scope.
No. Judgment & Checking Solution of Trouble
1. failure of oil pressure gauge replacing the new oil pressure gauge
2. oil filter or oil cooler is dirty cleaning/replacing oil filter or oil cooler
3. space is too large between lever & shaft of rocker a. checking lubrication of air valves
b. replacing the relevant parts if necessary
4. damage of oil suction tube replacing gasket or tube
5. failure of safety valve in the oil pump a. cleaning safety valve
b. replacing damaged parts
6. failure of oil pump repairing or replacing oil pump
7. space is too large between crankshaft & main bearing a. checking wear-out conditions
b. replacing the parts if necessary
18. Normal Troubles of Engine
No. Judgment & Checking Solution of Trouble
1. oil-feeding volume is too much in the oil pan draining the redundant oil
2. temperature of oil is much high checking oil cooler
3. oil is too much in the air valves checking both heads of rocker shaft
4. wear-out of air valve guide checking cylinder cover and replacing the guide
5. wear-out of piston rings & cylinder liner replacing the new parts
6. seal ring of turbocharger is damaged a. checking whether there is oil in the air intake tube
b. repairing the turbocharger
Description of trouble: oil consumption of engine is too much.
19. Normal Troubles of Engine
Description of trouble: exhaust gas of engine is black.
No. Judgment & Checking Solution of Trouble
1. air isn’t abundant when fuel is burning checking air filter, air intake pipe & turbocharger
2. failure of the fuel injector testing the injector, replacing the nipple
3. space of air valve is incorrect adjusting the space of air valve
4. seal of air valve is bad a. checking air valve & inseat of valve
b. repairing if necessary
20. Normal Troubles of Engine
Description of trouble: there is mechanical noise inside the engine.
No. Judgment & Checking Solution of Trouble
1. big wear-out of bearing of connecting rod checking bearing of connecting rod & crankshaft
2. big wear-out of thrust bearing a. checking or replacing the part
b. checking axial space of crankshaft
3. wear-out or damage of timing gear replacing timing gear
4. damage of crankshaft
5. air valves hit the piston of engine
21. Normal Troubles of Torque Converter
Quality of torque converter is stable and its failure rate is very low. Once the faults happen, it is easy to be
judged. We can judge the failures by draining the oil. Normally there are around 3 litres oil remained in the
torque converter. If oil volume is big, it states that seal ring or scavenging pump is damaged. If there is
aluminium powder in the oil, it states that body of scavenging pump is worn & teared. In this case, you can
disassemble the torque converter.
Description of trouble: screen of scanenging pump is blocked
Diagnosis of trouble: body of torque converter will become hot around 30 minutes or 1 hour later after
starting the bulldozer.
Judgment & Checking: cleaning the filter element and replacing it if necessary.
22. Normal Troubles of Torque Converter
Description of trouble: Inner parts of torque converter are damaged
Diagnosis of trouble: body of torque converter will become hot within 30 minutes later after starting the bulldozer.
Judgment & Checking:
1. Seal ring of stator seat is worn out or damaged
2. Oil leakage caused by loosening of connecting bolt between pump and case
3. Oil leakage caused by falling of oil-draining plug in the pump
23. Normal Troubles of Torque Converter
Description of trouble: Oil-feeding is shortage.
Diagnosis of trouble: there is air bubble (oil) emerging in the torque converter. Meantime small noise occurs in
the torque converter.
Judgment & Checking:
1. Oil-feeding is shortage as relief valve is clipped at open position.
2. Oil-feeding is shortage as the stroke of regulator valve cann’t reach the nomal level.
Solution of trouble:
1. Checking and cleaning the relief valve.
2. Checking and cleaning the regulator valve.
24. Normal Troubles of Torque Converter
Description of trouble: Oil temperature in torque convereter is too high
Judgment & Checking:
1. checking oil volume in the torque converter
2. checking scavenging pump & its filter element
3. judging whether oil cooler is blocked by checking oil pressure of oil cooler
4. crackle of torque converter also can cause high temperature
25. Normal Troubles of Transmission Case
Description of trouble: trouble of transmission control valve
Diagnosis of trouble: walking system is powerless
Judgment & Checking:
confirming that universal joint rotates nomally at first, then testing inlet pressure of transmission control valve. If it
isn’t stable, it states that spring of control valve is broken.
Solution of trouble:
replacing the spring of control valve
26. Normal Troubles of Transmission Case
Description of trouble: failure of some transmission gears
Judgment & Checking:
1. If the 1st forward gear is powerless and also the 1st reverse gear is abnormal, it states that there is fault with
1st gear gear. In this case, please repair it by dismantling transmission case.
2. the above method is also suitable for judging the fault of other gear shifts.
3. please checking whether there is oil leakage on the surface of transmission case by the pressure test after
dismantling the transmission box. crackle of transmission case can be judged by this way.
27. Normal Troubles of Transmission Case
Description of trouble: high oil temperature caused by transmission control valve
Diagnosis of trouble: oil temperature is abnormal half an hour later after bulldozer starts to work.
Judgment & Checking:
oil pressure is normal and bulldozer can continue to work once oil temperature comes down, but the failure will
appear again soon. In this case, failure is perhaps caused by control valve. The reason is that control valve is
clipped at half-opening status which causes oil temperature rises as oil flow becomes small.
Solution of trouble:
replacing the upper body of transmission control valve
28. Normal Troubles of Transmission Case
Description of trouble: gear of transmission is ineffective
Judgment & Checking:
1. seal ring of ineffective gear is damaged or wrong fixxed.
2. crackle occurres in the oil way of ineffective gear or other oil leakages
3. failure of transmission control valve
(1) damage of o-ring in the control valve housing
(2) spool of valve is stopped at the closing status
Solution of trouble:
please dismantle the control valve and inject compressed air into 5 oil inlettes, connectting voice of the clutch will
be heard normally. Otherwise, we can hear the voice of air leakage and it confirms the failure of clutch.
29. Normal Troubles of Transmission Case
Description of trouble: bulldozer cann’t stop when gear shift lever stays in adiaphorous status.
Judgment & Checking:
1. adjustment of gear shift lever is incorrect.
2. failure happens in the clutch disk of reverse gear when bulldozer goes back
3. failure happens in the clutch disk of forward gear when bulldozer goes ahead
Solution of trouble:
1. adjusting gear shift lever to the adiaphorous status
2. checking and replacing the damaged parts
3. checking and replacing the damaged parts
30. Normal Troubles of Transmission Case
Description of trouble: bulldozer doesn’t move in the normal conditions.
Judgment & Checking:
1. bad wear-out of transmission pump
2. oil seal of input shaft is damaged in the transmission pump
3. oil level is low in the transmission box
4. air leakage happens in the oil pipe
Solution of trouble:
1. replacing new transmission pump
2. checking and replacing the oil seal
3. adding the lubrication oil in the transmission box
4. checking joint hose, strainer & seal parts
31. Normal Troubles of Transmission Case
Description of trouble: there is a short waiting when the gear is shifted.
Judgment & Checking:
The reason of this failure is that spring of booster is broken and it delays the rising time of oil pressure.
Solution of trouble:
Checking the booster of control valve and replacing the damaged spring
32. Normal Troubles of Transmission Case
Description of trouble: the 1st gear of transmission box is ineffective
Diagnosis of trouble: no pressure of 1st gear of transmission box, but the presure of other gears is normal.
Judgment & Checking:
The reason of this failure is that seal ring of 1st gear is worn-out or crackles happen in the body of cylinder.
Solution of trouble:
Replacing the body of cylinder
33. Normal Troubles of Transmission Case
Description of trouble: bulldozer will stop when the gear shift lever is converted into 2nd gear.
Judgment & Checking:
As clutch disk of 1st gear is damaged, its powers are counteracted when the gear shift lever is converted into
2nd gear, which makes the bulldozer can not move.
Solution of trouble:
Repairing the 1st gear of transmission case
34. Troubles & Solution of Steering Case
Description of trouble: cover of steering filter bulges because of high pressure
Reason of Failure:
Pressure regulating valve is failure as dirty oil or vein of valve body. It makes that oil presure rises rapiddly
and steering filter cover bulges because of the inner high pressure.
Solution of trouble:
1. Repalcing dirty oil & filter element
2. Cleaning the presure regulating valve
35. Troubles & Solution of Steering Case
Description of trouble: no steering in one side
Reason of Failure:
1. O-ring of S-pipe is damaged
2. Oil seal of the steering clutch is damaged
3. Piston seal of the steering clutch is damaged
4. Connecting bolt of the inner drum of steering clutch is loosenning
Solution of trouble:
Checking points of oil leakage and replacing damaged seal parts
36. Troubles & Solution of Steering Case
Description of trouble: steering is failure when the machine is in the hot status.
Reason of Failures:
the hose connectting steering pump & strainer becomes soft when it is heated as the hose is aging. In this
condition, oil cann’t pass as the hose is pressed under the action of steering pump, which causes the
failure of steering.
Solution of trouble:
checking the hose and replacing this part if necessary.
37. Troubles & Solution of Steering Case
Description of trouble: steering is failure when the throttle is openned in a small degree; and
steering is normal when the throttle is completely opened.
Reason of Failures:
the steering clutch cann’t be openned as oil pressure is too small when the engine rotates at a low speed.
but the steering cluth will be openned along with increase of revolution speed of the engine.
Solution of trouble:
checking the steering pump and replacing it if necessary.
38. Troubles & Solution of Steering Case
Description of trouble: bulldozer will stop when operator pulls the steering control lever in one side.
Reason of Failures:
the steering clutch in the other side is also openned, and failure takes place not in control side.
Solution of trouble:
checking the brake valve and steering clutch in the above place
39. Troubles & Solution of Steering Case
Description of trouble: brake is powerless
Reason of Failures:
1. wear-out of brake band is large
2. adjustment of brake control lever is not correct
3. seal failure of brake booster valve
4. seal failure of brake safety valve
Solution of trouble:
adjusting the brake band and replacing the parts if necessary
40. Troubles & Solution of Steering Case
Description of trouble: bearing of central transmission shaft is damaged
Diagnosis of trouble: steering in one side is ineffective; steering pressure & braking pressure are zero
in this side.
Reason of Failures:
after the damage of the above bearing, it causes seal ring wears-out as anomalous rotation of central
transmission shaft.
41. Troubles & Solution of Steering Case
Description of trouble: oil in the hydraulic oil tank flows into the steering case
Reason of Failures:
Oil seal is damaged in the hydraulic pump.
Solution of trouble:
Replacing oil seal of the hydraulic pump.
42. Troubles & Solution of Working Equipment
Description of trouble: failure of blade lifting cylinder
Diagnosis of trouble:natural fall of the blade exceeds the normal scope after the balde is lifted.
Reason of Failures:
1. blade lifting cylinder is hurted as piston rod rubs the body of cylinder directly, which will produce a lot iron
filings in the oil return pipes.
2. blade lifting control valve is damaged
Solution of trouble:
1. draining the oil, cleaning the oil return pipe and replacing lifting cylinder
2. replacing the new blade lifting control valve
43. Troubles & Solution of Working Equipment
Description of trouble: high temperature of hydraulic oil tank (normal temperature is < 80℃)
Reason of Failures:
1. control lever of direction-shift valve (servo valve to hydraulic oil tank) is adjusted incorrectly which causes
high oil pressure.
2. failure caused by disorder of ripper direction-shift valve
Solution of trouble:
1. adjusting the control lever to make direction-shift valve is in the adiaphorous status.
2. adjusting the spring of ripper direction-shift valve to adiaphorous status
44. Troubles & Solution of Working Equipment
Description of trouble: abnormal falling of the cylinder
Reason of Failures:
1. failure of quick drop valve, piston valve & wear-out of piston seal
2. o-ring of suction valve is damaged
3. there is sand hole in the body of cylinder
Solution of trouble:
1. repairing quick drop valve, replacing piston seal and checking piston valve (inside the blade lifting cylinder)
2. replacing o-ring of suction valve
3. replacing new body of cylinder
45. Troubles & Solution of Working Equipment
Description of trouble: hard control of working equipment
Reason of Failures:
1. hydraulic pump is worn-out and output pressure is below 8Mpa
2. failure of servo valve
3. incorrect adjustment of control lever (servo valve to direction-shift valve)
4. direction-shift valve is clipped
Solution of trouble:
1. checking and replacing
2. checking and replacing
3. checking and adjusting the control lever to adiaphorous status
4. cleaning and replacing if necessary
46. Other Troubles
Description of trouble: track shoe cann’t be tensed.
Reason of Failures:
1. wear-out of track link
2. grease cann’t be injected into the cylinder
3. oil seal of the cylinder is damaged
4. there is crackle in the cylinder
Solution of trouble:
1. replacing track link
2. changing another grease injector
3. replacing new oil seal
4. replacing new cylinder
