SANY Crawler Hydraulic Excavator SY365H-9, SY365BH-9. Shop Manual (2014)

7-91

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-8 Bucket speed slow

Failure information

●

The bucket moves slowly.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of right
pilot valve (bucket
circuit)

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Bucket control lever

Pilot valve output pressure

NEUTRAL

0 {0}

Bucket DIG or Bucket DUMP

≥

3.5MPa

{36 kg/cm

}

2 Press sensor failure

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Check the sensor by replacing it with a new one.

Malfunction of
bucket control valve
(spool)

Spool of bucket control valve may have malfunction. Check it directly.

Malfunction or
defective seal of
bucket control valve
(relief valve and
makeup valve)

Relief valve and makeup valve in bucket control valve may have mal-
function or defective seal. Check the valves directly.

Failure of bucket
cylinder

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Charge the bucket with a load of approximate 1260 kg. Cut off the oil
passage to the high-pressure side of the cylinder. Disconnect the cyl-
inder from the main valve. Measure the displacement of piston for 15
minutes after the cylinder becomes stable. If the measured value is
greater than 10 mm, it is deemed that cylinder has a defective seal.
For more information on the measuring procedure see

"Hydraulic

Drift of Work Equipment - Test" on page 6-34.

7-92

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-9 Work equipment cylinders no response in separate operation

Failure information

●

Boom cylinder gives no response in separate operation.

●

Arm cylinder gives no response in separate operation.

●

Bucket cylinder gives no response in separate operation.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of pilot
valve

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Work equipment control lever

Pilot valve output pressure

NEUTRAL

0 {0}

DIG or DUMP

≥

3.5MPa

{36 kg/cm

}

2 Press sensor failure

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Check the sensor by replacing it with a new one.

Malfunction of con-
trol valve (spool)

Spool of control valve may have malfunction. Check it directly.

7-93

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-10 Work equipment drifts excessively

Failure information

(1)

●

The boom drifts at excessive speed.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of boom
cylinder

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Charge the bucket with a load of approximate 1260 kg. Cut off the oil
passage to the high-pressure side of the cylinder. Disconnect the cyl-
inder from the main valve. Measure the displacement of piston for 15
minutes after the cylinder becomes stable. If the measured value is
greater than 10 mm, it is deemed that cylinder has a defective seal. For
more information on the measuring procedure see

"Hydraulic Drift of

Work Equipment - Test" on page 6-34.

Failure of boom
retaining valve

Boom retaining valve or pilot valve may be worn or sluggish. Check the
valves.

Malfunction or
defective seal of
boom control valve
(relief valve and
makeup valve)

The relief valve and the makeup valve in the boom control valve may
have a defective seal. Check the seals.

Failure of boom
valve spool

Spool of boom valve may be worn excessively. Check the spool.

7-94

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

Failure information

(2)

●

The arm drifts excessively.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of arm
cylinder

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Cut off the oil passage to the high-pressure side of the cylinder. Discon-
nect the cylinder from the main valve. Measure the displacement of pis-
ton for 15 minutes after the cylinder becomes stable. If the measured
value is greater than 10 mm, it is deemed that cylinder has a defective
seal. For more information on the measuring procedure see

"Hydraulic

Drift of Work Equipment - Test" on page 6-34.

Malfunction or
defective seal of
arm control valve
(relief valve and
makeup valve)

Relief valve or makeup valve of the arm control valve may be defective.
Check the valves directly.

★

The performance of seal can be judged by replacing it with another

relief valve or makeup valve.(Never replace it with the boom-down
relief valve or makeup valve as their pressures are set differently.)

Failure of arm
retaining valve

Arm retaining valve or pilot valve may be worn or sluggish. Check the
valves.

Failure of arm
valve (spool)

Arm valve (spool) may be worn excessively. Check it directly.

7-95

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

Failure information

(3)

●

The bucket drifts excessively.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of bucket
cylinder

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Bucket control levers

Leakage from bucket cylinder

Bucket-dig relief

20 ml/min

Defective seal of
bucket control valve
(relief valve and
makeup valve)

Seal of relief valve or makeup valve of bucket control valve may be
defective. Check it directly.

★

The performance of seal can be judged by replacing it with anoth-

er relief valve or makeup valve. (Never replace it with the boom-
down relief valve or makeup valve as their pressures are set dif-
ferently. )

Defective seal of
bucket control valve
(spool)

Seal of bucket control valve spool may be defective. Check it direct-
ly.

7-96

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

Failure information

●

Work equipment moves sluggishly.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of
arm regenera-
tion valve

Regeneration valve of arm may have malfunction. Check it directly.

Malfunction of
control valve
(relief valve and
makeup valve)

Relief valve or makeup valve of control valve may have malfunction.
Check it directly.

●

For arm and boom, whether a valve has malfunction can be judged
by replacing it with another relief valve or makeup valve.

(Never replace it with the boom-down relief valve or makeup valve as
their pressures are set differently. )

H-11 Work equipment moves sluggishly

H-12 Other work equipment moves while single oil circuit is relieved

Failure information

●

Other work equipment moves while single oil circuit of certain work equip-
ment is relieved.

Related information

●

Set the working mode to S to perform troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Defective seal
of control valve

Seal of control valve may be defective. Check it directly.

7-97

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-13 Travel speed drops considerably while swinging and travelling

Failure information

●

Travel speed drops considerably in swinging plus travelling operation.

Related information

●

If the travel speed is low in only travelling operation, check

rst ac-

cording to H-15.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Failure of straight
travel valve

The straight travel valve gives no response. Check the spool and
the logic oil circuit drain port.

7-98

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-14 Machine deviates during travel

Failure information

●

Machine deviates during travel.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of travel pilot
valve

●

Stop the engine before troubleshooting. Perform trouble-
shooting while the engine is running at high idle.

Travel control lever

Pilot valve output pressure

Forward

Reverse

3.5~3.9 MPa

{ 36~40 kg/cm

}

Difference occurs between
left and right output

0.4 MPa {4 kg/cm

}

Malfunction of pilot relief
valve

●

Stop the engine before troubleshooting. Perform trouble-
shooting while the engine is running at high idle.

Control lever

Control circuit source pressure

All levers in NEUTRAL

3.5~3.9 MPa

{ 36~40 kg/cm

}

Failure of regulator

Check the regulator by swapping the front and back regulators.

Sluggishness of propor-
tional solenoid valve

●

Stop the engine before troubleshooting. Perform trouble-
shooting while the engine is running at high idle.

Travel control lever

Proportional valve output pressure

Operate both control levers

≤

0.1 MPa

Sluggishness of travel con-
trol valve (spool)

Check the valve spool to see whether it works well.

Internal leakage of central
swivel joint

Check it by swapping the lines.

Malfunction of travel motor

●

Stop the engine before troubleshooting. Perform trouble-
shooting while the engine is running at high idle.

Travel control lever

Leakage of travel motor

Travel relief

27.2 ml/min

Failure of

nal drive

Final drive may have internal defect. Check it directly.

●

Internal defect of the

nal drive can be determined through

abnormal noise, abnormal heat, and metal powder or debris
contained in the oil drained.

Failure of travel pilot pres-
sure sensor

Travel control levers

Pilot valve output pressure

Forward or backward

The monitor reads:

3.5~3.9MPa

{ 36~40 kgf/cm

}

Output difference between the

left and the right

0.4 MPa {4 kgf/cm

}

Check it by swapping.

7-99

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-15 Travel speed low

Failure information

●

Machine travel speed is low.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of travel
pilot valve

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Travel control lever

Pilot valve output pressure

Forward or reverse

3.5~3.9 MPa

{ 36~40 kg/cm

}

Difference occurs between front

output and rear output

≤

0.4 MPa

≤

{4 kg/cm

}

Malfunction of pilot
relief valve

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Control lever

Control circuit source pressure

All levers in NEUTRAL

3.5~3.9 MPa

{ 36~40 kg/cm

}

3 Sensor failure

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Travel speed

Travel control

Low

Operation

3.5~3.9 MPa

{ 36~40 kgf/cm

}

High

Operation

3.5~3.9 MPa

{ 36~40 kgf/cm

}

Check it by replacement.

Malfunction of travel
control valve (spool)

Spool of travel control valve may have malfunction. Check it directly.

Malfunction of
travel control valve
(makeup valve)

The makeup valve in travel control valve may have malfunction. Check it
directly.

Failure of travel mo-
tor

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Travel control lever

Oil leakage of travel motor

Travel relief

27.2 ml/min

7 Failure of

nal drive

Final drive may have internal defect. Check it directly.

●

Internal defect of the

nal drive can be determined through abnormal

noise, abnormal heat, and metal powder or debris contained in the
oil drained.

7-100

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-16 Machine not steered easily or steering power low

Failure information

●

Machine is not steered well or steering power is low

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of travel
pilot valve

●

Stop the engine before troubleshooting. Perform troubleshoot-
ing while the engine is running at high idle.

Travel control lever

Pilot valve output pressure

Both sides in NEUTRAL

0 {0}

Either side operated

3.5~3.9 MPa

{ 36~40 kg/cm

}

Failure of travel pilot
pressure sensor

●

Stop the engine before troubleshooting. Perform troubleshoot-
ing while the engine is running at high idle.

Travel control lever

Pilot valve output pressure

Both sides operated

3.5~3.9 MPa

{ 36~40 kgf/cm

}

Either side operated

3.5~3.9 MPa

{ 36~40 kg/cm

}

Malfunction of travel
control valve (spool)

Spool of travel control valve may have malfunction. Check it direct-
ly.

Malfunction of travel
control valve (makeup
valve)

The makeup valve in travel control valve may have malfunction.
Check it directly.

Failure of travel motor
(relief valve)

Seal of relief valve in travel motor may be defective. Check it di-
rectly.

●

The failure of seal can be determined by swapping the front
and back motors or the left and right motors.

Failure of travel motor
(check valve)

Seal of check valve in travel motor may be defective. Check it di-
rectly.

●

The failure of seal can be determined by swapping the front
and back motors or the left and right motors.

7-101

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-17 Travel speed cannot be shifted

Failure information

●

Travel speed cannot be shifted.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of travel
speed shifting sole-
noid valve

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Travel speed

Travel control lever

Solenoid valve output

pressure

Operated

0 {0}

Operated

3.5~3.9 MPa

{ 36~40 kg/cm

}

Failure of travel mo-
tor (in speed change)

Speed shifting assembly of travel motor may have malfunction.

Check it directly.

7-102

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-18 Travel system fails (only at one side)

Failure information

●

One side of the tracks cannot make a turn.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Defective seat of
travel control valve
(makeup valve)

Seat of makeup valve in travel control valve may have malfunction.
Check it directly.

Defective seat of
travel motor (relief
valve)

Seat of relief valve in travel control valve may have malfunction.

Check it directly.

Defective seat of
travel motor valve
(makeup valve)

Seat of check valve in travel motor valve may have malfunction.

Check it directly.

Speed of travel mo-
tor drops.

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Travel control lever

Leakage from travel motor

Travel relief

27.2 ml/min

5 Failure of

nal drive

Final drive may have internal defect. Check it directly.

●

Internal defect of final drive can be determined with abnormal
noise, overheat, and metal powder or debris contained in the oil
drained.

Failure of pilot pres-
sure sensor

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Travel control lever

Pilot valve output pressure

Forward or backward

The monitor read: 3.5~3.9 MPa

{ 36~40 kgf/cm

}

Output difference between the left

and the right

0.4 MPa {4 kgf/cm

}

Check it by swapping.

7-103

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-19 Swing operation fails

Failure information (1)

●

Upper structure fails to swing in either direction.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of
swing motor (park-
ing brake)

Parking brake of swing motor may have malfunction. Check it directly.

Improper adjust-
ment or malfunc-
tion of swing motor
(relief valve)

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Swing control lever

Swing relief pressure

Swing relief

25.5~28.5 MPa

{260~291 kg/cm

}

If oil pressure does not become normal after adjustment, swing motor
relief valve may have malfunction or internal defect. Check the relief
valve directly.

Failure of swing
motor

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Swing control lever

Leakage from swing motor

Swing relief

≥

10 ml/min

Failure of swing
mechanism

Swing mechanism may have internal defect. Check it directly.

●

Internal defect of swing mechanism can be determined with ab-
normal noise, overheat, and metal powder or debris contained in
the oil drained.

7-104

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

Trouble (2)

●

Upper structure only fails to swing in one direction.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of
pilot valve

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Left control lever

Pilot valve output pressure

NEUTRAL

0 {0}

Swing

≥

3.5MPa {

≥

36 kg/cm

}

Malfunction of
swing control
valve (spool)

Spool of swing control valve may have malfunction. Check it directly.

Defective seal
of swing motor
(makeup valve)

Seal of makeup valve in swing motor may have defect. Check it directly.

●

Failure of the seal can be determined by swapping the right and left
makeup valves and check for any changes.

7-105

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

H-20 Swing acceleration poor or swing speed low

Failure information (1)

●

Swing acceleration is poor, or swing speed is low.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of
swing motor (park-
ing brake)

Parking brake of swing motor may have malfunction. Check it directly.

Improper adjust-
ment or malfunc-
tion of swing motor
(relief valve)

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Swing control lever

Swing relief valve

Swing relief

25.5~28.5 MPa

{260~291 kg/cm

}

If oil pressure does not become normal after adjustment, swing motor
relief valve may have malfunction or internal defect. Check the relief
valve directly.

Failure of swing
motor

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Swing control lever

Leakage from swing motor

Swing relief

≤

10 ml/min

Clogging of brake
control lines

Disassemble, clean and check.

7-106

Troubleshooting

SY365(B)H-9 Crawler Hydraulic Excavator

Failure information (2)

●

Swing acceleration is only poor on one side, or swing speed is
low.

Related information

●

Set working mode to S and fuel control dial at position 10 to carry
out troubleshooting.

Possible causes and standard values

Cause

Standard values and troubleshooting references

Malfunction of
pilot valve

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Swing control lever

Pilot valve output pressure

NEUTRAL

0 {0}

Left swing

Right swing

≥

3.5MPa {

≥

36 kg/cm

}

Malfunction of
swing motor
(pressure com-
pensation valve)

Pressure compensation valve of swing motor may have malfunction.
Check it directly.

Defective seal
of swing motor
(makeup valve)

Seal of makeup valve in swing motor may have defect. Check it directly.

●

Swap the left and right makeup valves and observe the result to de-
termine whether the seal fails.

One-side leak-
age of swing pilot
pressure sensor
(shuttle valve)

●

Stop the engine before troubleshooting. Perform troubleshooting
while the engine is running at high idle.

Swing control lever

Pilot valve output pressure

NEUTRAL

0 {0}

Left swing

Right swing

3.5~3.9MPa {36~40 kg/cm

}

SANY Crawler Hydraulic Excavator SY365H-9, SY365BH-9. Shop Manual (2014) - page 28