SANY Crawler Hydraulic Excavator SY215CLC (CUMMINS QSB6.7 engine). Shop Manual

Troubleshooting

SY215C

7-106

H-13 Travel speed drops considerably while swinging and travelling

Trouble

●

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 value in

normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Failure of straight
travel valve

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

Troubleshooting

SY215C

7-107

H-14 Machine deviates during travel

Trouble

●

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 value in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of travel pilot

valve

★

Stop the engine. Perform troubleshooting 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/cm²}

Difference occurs between

left and right output

0.4 MPa {4 kg/cm²}

Malfunction of pilot relief

valve

★

Stop the engine. 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/cm²}

Failure of regulator

Check the regulator by swapping the front and back regulators.

Sluggishness of proportion-

al solenoid valve

★

Stop the engine. Perform troubleshooting 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. Perform troubleshooting 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

★

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

Travel control lever

Pilot valve output pressure

Forward

Reverse

3.5~3.9MPa

{ 36~40 kg/cm²}

Difference occurs between

left and right output

0.4 MPa {4 kg/cm²}

Check the sensor by swapping it with another one.

Troubleshooting

SY215C

7-108

H-15 Travel speed or power is low

Trouble

●

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 value in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of travel

pilot valve

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Travel control lever

Pilot valve output pressure

Forward

Reverse

3.5~3.9 MPa

{ 36~40 kg/cm²}

Difference occurs between left and

right output

≤

0.4 MPa

≤

{4 kg/cm²}

Malfunction of pilot

relief valve

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Control lever

Control circuit source pressure

All levers in "NEUTRAL"

3.5~3.9 MPa

{ 36~40 kg/cm²}

Failure of sensor

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Travel speed

Travel control lever

Reading on monitor

Operated

3.5~3.9 MPa

{ 36~40 kg/cm²}

Operated

3.5~3.9 MPa

{ 36~40 kg/cm²}

Check the sensor by replacing it with another one.

Malfunction of travel
control valve (spool)

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

Malfunction of travel

control valve (make-

up valve)

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

Failure of travel mo-

tor

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Travel control lever

Oil 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 abnor-

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

Troubleshooting

SY215C

7-109

H-16 Machine is not steered well or steering power is low

Trouble

●

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 value in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of travel

pilot valve

★

Stop the engine. Perform troubleshooting 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/cm²}

Malfunction of travel

pilot pressure sensor

★

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

Travel control lever

Solenoid valve output pressure

Both sides operated

3.5~3.9 MPa

{ 36~40 kg/cm²}

Either side operated

3.5~3.9 MPa

{ 36~40 kg/cm²}

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 motor

(relief valve)

Seal of relief valve in travel motor may be defective. Check it
directly.

★

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
directly.

★

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

Troubleshooting

SY215C

7-110

H-17 Travel speed cannot be changed

Trouble

●

Travel speed cannot be changed.

Related information

●

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

Possible causes and standard value in

normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of travel

speed shifting solenoid

valve

★

Stop the engine. 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/cm²}

Failure of travel motor (in

speed change)

Speed shifting assembly of travel motor may have malfunction.
Check it directly.

Troubleshooting

SY215C

7-111

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

Trouble

●

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 value in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

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 motor
drops.

★

Stop the engine. Perform troubleshooting while the engine is run-
ning 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.

Defective pilot pressure
sensor

★

top the engine. Perform troubleshooting while the engine is run-

ning at high idle.

Travel control lever

Pilot valve output pressure

Forward

Reverse

3.5~3.9MPa

{ 36~40 kg/cm²}

Difference occurs between left and
right output

0.4 MPa {4 kg/cm²}

Check it with swapping method.

Troubleshooting

SY215C

7-112

H-19 Swing operation fails

Trouble (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 value in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of swing

motor (parking brake)

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

Improper adjustment

or malfunction of

swing motor (relief

valve)

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Swing control lever

Swing relief pressure

Swing relief

25.5~28.5 MPa

{260~291 kg/cm²}

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. Perform troubleshooting while the engine is run-
ning 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
abnormal noise, overheat, and metal powder or debris contained
in the oil drained.

Troubleshooting

SY215C

7-113

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 value in

normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of pilot

valve

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Left control lever

Pilot valve output pressure

"NEUTRAL"

0 {0}

Swing

≥

3.5MPa {

≥

36 kg/cm²}

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.

Troubleshooting

SY215C

7-114

H-20 Swing acceleration poor or swing speed low

Trouble (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 value in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of swing

motor (parking brake)

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

Improper adjustment

or malfunction of

swing motor (relief

valve)

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Swing control lever

Swing relief valve

Swing relief

25.5~28.5 MPa

{260~291 kg/cm²}

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 mo-

tor

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Swing control lever

Leakage from swing motor

Swing relief

≤

10 ml/min

Clogging of brake

control lines

Disassemble, clean and check.

Troubleshooting

SY215C

7-115

Trouble (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 value in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of pilot

valve

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Swing control lever

Pilot valve output pressure

"NEUTRAL"

0 {0}

Left swing

Right swing

≥

3.5MPa {

≥

36 kg/cm²}

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 di-
rectly.

★

Swap the left and right makeup valves and observe the result in
order to determine whether the seal fails.

One-side leakage of

swing pilot pressure

sensor (shuttle valve)

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Swing control lever

Pilot valve output pressure

"NEUTRAL"

0 {0}

Left swing

Right swing

3.5~3.9MPa {36~40 kg/cm²}

Troubleshooting

SY215C

7-116

H-21 Upper structure overruns remarkably when it stops swinging

Trouble (1)

●

Upper structure overruns remarkably when it stops swinging in
both directions.

Related information

●

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

Possible causes and standard value in normal

state

Cause

Standard value in normal state/Remarks on troubleshooting

Improper adjustment

or malfunction of swing

motor (relief valve)

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Swing control lever

Swing relief pressure

Swing relief

25.5~28.5 MPa

{260~291 kg/cm²}

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

2 Failure of swing motor

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Control lever

Leakage from swing motor

Swing relief

≤

10 ml/min

Trouble (2)

●

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

Related information

●

Set the working mode at gear (10) of power mode (S) to perform
troubleshooting.

Possible causes and standard value in nor-

mal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of pilot valve

★

Stop the engine. 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/cm²}

Malfunction of swing con-

trol valve (spool)

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

ly.

Malfunction or defec-

tive seal of swing motor

(makeup valve)

Seal of makeup valve in swing motor may be defective. Check it
directly.

★

Swap the left and right makeup valves and observe the result
in order to determine whether the seal fails.

Troubleshooting

SY215C

7-117

H-22 Large shock is produced when upper structure stops swinging

Trouble

●

Large shock is produced when upper structure stops swinging.

Related information

●

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

Possible causes and standard value in normal

state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of swing

pilot valve

★

Stop the engine. Perform troubleshooting while the engine is run-
ning at high idle.

Swing control lever

Pilot valve output pressure

"NEUTRAL"

0 {0}

Left swing

Right swing

≥

3.5MPa {

≥

36 kg/cm²}

Malfunction of swing

reverse prevention

valve

Reverse prevention valve of swing motor may have malfunction.
Check it directly.

★

Replace the valve with a new on in order to determine whether the
valve fails.

Malfunction of swing

relief valve

Swing relief valve may be worn or sluggish.

H-23 High noise is produced when upper structure stops swinging

Trouble

●

High noise is produced when upper structure stops swinging.

Related information

●

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

Possible causes and standard value in normal

state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction of back
pressure valve

Back pressure valve may have malfunction. Check it directly.

Malfunction of swing
motor (relief valve)

Relief valve of swing motor may have malfunction. Check it directly.

Malfunction of swing
motor (makeup valve)

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

★

Swap the left and right makeup valves and observe the result in
order to determine whether the seal fails.

Failure of swing mecha-
nism

The swing mechanism is suspected of an internal failure. Check the
inside of the machinery itself.

★

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

Troubleshooting

SY215C

7-118

H-24 Swing drift excessive

Trouble (1)

●

Hydraulic drift of swing is large (when swing holding brake is ap-
plied).

Related information

●

When swing lock switch is turned ON or when swing holding
brake release switch is in normal position, swing holding brake
operates and upper structure is

xed with disc brake.

Possible causes and standard value

in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Failure of swing hold-
ing brake control lines

Swing holding brake control lines and holding brake pilot valve may be
defective. Check them directly.

Malfunction of swing
motor (parking brake)

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

Trouble (2)

●

Hydraulic drift of swing is large (when swing holding brake is re-
leased).

Related information

●

When swing holding brake release switch is in release position,
swing holding brake is released and upper structure is secured
by only hydraulic pressure.

Possible causes and standard value

in normal state

Cause

Standard value in normal state/Remarks on troubleshooting

Malfunction or defec-
tive seal of swing
control valve (spool)

Swing control valve spool may have malfunction or defective seal.
Check it directly.

Failure of swing motor
(relief valve)

Seal of relief valve in swing motor may be defective. Check it directly.

Failure of swing motor
(makeup valve)

Seal of makeup valve in swing motor may be defective. Check it di-
rectly.

Disassembly and Assembly

SY215C

8-1

8 Disassembly and Assembly

8.1 Reading Guide ......................................................................................................... 8-3

8.2 Operating Precautions ............................................................................................. 8-7

8.3 Radiator AS - Remove and Install...........................................................................8-11

8.4 Engine and Hydraulic Pump AS - Remove and Install .......................................... 8-15

8.5 Final Drive AS - Remove and Install ...................................................................... 8-22

8.6 Final Drive AS - Disassemble and Assemble......................................................... 8-24

8.7 Swing Motor and Swing Drive AS - Remove and Install ........................................ 8-33

8.8 Swing Motor and Swing Drive AS - Disassemble and Assemble........................... 8-35

8.9 Idler AS - Disassemble and Assemble ................................................................... 8-45

8.10 Sprocket - Remove and Install............................................................................. 8-49

8.11 Track AS - Remove and Install ............................................................................. 8-50

8.12 Swing Bearing AS - Remove and Install .............................................................. 8-53

8.13 Swing Platform AS - Remove and Install ............................................................. 8-55

8.14 Swivel Joint AS - Remove and Install .................................................................. 8-59

8.15 Swivel Joint AS - Disassemble and Assemble ..................................................... 8-62

8.16 Hydraulic Tank AS - Remove and Install .............................................................. 8-64

8.17 Control Valve AS - Remove and Install ................................................................ 8-67

8.18 Hydraulic Pump AS - Remove and Install ............................................................ 8-72

8.19 Middle Oil Seal (Hydraulic Pump Input Shaft)- Remove and Install .................... 8-77

8.20 Pilot Valve AS (Work Equipment) - Disassemble and Assemble ......................... 8-78

8.21 Pilot Valve AS (Travel) - Disassemble and Assemble .......................................... 8-80

Disassembly and Assembly

SY215C

8-2

WARNING

Always read the Safety section of this man-
ual before attempting to operate or service
this equipment. Failure to do so could re-
sult in machine damage, personnel injury
or death.

8.22 Hydraulic Cylinder AS - Disassemble and Assemble........................................... 8-82

8.23 Work Equipment AS - Remove and Install ........................................................... 8-94

8.24 Air Conditioner AS - Remove and Install.............................................................. 8-97

8.25 Counterweight AS - Remove and Install ............................................................ 8-101

8.26 Cab AS - Remove and Install............................................................................. 8-103

8.27 Cab Window Glass – Disassemble and Assemble ............................................ 8-108

8.28 Front Window AS - Disassemble and Assemble................................................ 8-124

8.29 Monitor - Remove and Install ............................................................................. 8-133

8.30 Controller AS - Remove and Install.................................................................... 8-134

8.31 Radio ................................................................................................................. 8-135

8.32 Battery ............................................................................................................... 8-139

8.33 Start Switch........................................................................................................ 8-142

8.34 Fuse Box............................................................................................................ 8-145

8.35 Wiper ................................................................................................................. 8-146

8.36 Relay.................................................................................................................. 8-151

8.37 Sensor ............................................................................................................... 8-155

8.38 Connector Terminals - Insert and Remove ........................................................ 8-157

Disassembly and Assembly

SY215C

8-3

DISASSEMBLY AND ASSEMBLY

8.1 Reading Guide

8.1.1 Removing and Installing an Assembly

8.1.1.1 Special tools

●

Special tools for removal and installation of
machine parts are listed.

●

Necessary characteristics of the tools are
noted in the list of special tools.

■

: Special tools that cannot be replaced

and must be used.

●

: Very useful tools, which can be

replaced with commercially available
ones.

8.1.1.2 Removal

●

The "Removal" section contains procedure,
precautions and the amount of oil or water
to be discharged.

●

The symbols used the in the "Removal"
section are described below:

This symbol indicates that safety-

related precautions must be ob-
served when doing the job.

★

This symbol is followed by instruc-

tions or precautions when perform-
ing a procedure.

This symbol indicates related rules

and precautions that must be
obeyed when installing the pats.

This symbol indicates the amount of

oil or water to be discharged.

SANY Crawler Hydraulic Excavator SY215CLC (CUMMINS QSB6.7 engine). Shop Manual - page 30