SANY Crawler Hydraulic Excavator SY195C9, SY205C9, SY215C9, SY225C9. Service Manual

Testing and Adjusting

6.10

Track Tension - Test and Adjust

6.10.1 Testing

1. Move your machine forward for a distance

that is equal to the length of track on the
ground. Keep running the engine at low
idle. Park your machine slowly.

2. Place a straight bar on the track over idler

(1) and carrier roller (2).

NOTE: A straight angle steel bar is recom-
mended for this purpose as it has good
resistance to bending strain.

3. Measure the maximum clearance (a) be-

tween the upper surface of track and the
lower edge of the straight bar.

●

Max. clearance (a): 10~30 mm (0.4~1.2
in)

ZX215-1004026

6-25

Testing and Adjusting

NOTE: Add grease until the gap (b) be-
tween the idler guide and the track frame
end becomes zero. If the tension is till low,
it indicates that the pins and bushings are
seriously worn. Replace the pins and bush-
ings, or remove a piece of track shoe.

6.10.2 Adjusting

●

If track tension is incorrect, make adjust-
ment as per the following instruction.

ZX215-1004027

ZXT215-1004003

1. Reduce track tension

1) Loosen the valve (1) to discharge

grease. Tighten the valve after dis-
charging.

2) Check the track tension again as per

the above method after adjustment.

2. Increase track tension

1) Add grease through the grease fitting

(2) with a grease gun.

2) Check the track tension again as per

the above method after adjustment.

CAUTION

●

Do not loosen the valve over one turn.
If the valve is loosened too much, the
grease under high pressure may cause
the valve to eject.

Testing and Adjusting

6.11 Hydraulic Pressure in Hydraulic Circuits - Test and Adjust

Testing and adjusting tools

Part Number

Part Name

—

60038932

Hydraulic Tester

B210770000084

Adaptor

NOTE: The hydraulic pressure in work equip-
ment, swing and travel (hydraulic pump out-
put) circuits can be viewed on the monitor.

6.11.1 Measuring

1. Preparatory work before measuring

1) Remove the plug (1) and plug (2) for

measuring the hydraulic pressure.

●

Plug (1): For oil circuit of rear pump

●

Plug (2): For oil circuit of front pump

2) Install the priming adaptor and connect

it to the hydraulic tester.

●

Use an oil pressure gauge with a ca-
pacity of 40 MPa {408 kgf/cm²}.

3) Start the engine and keep it running

until the hydraulic pressure rises to a
point within the operational range.

ZX215-1004028

CAUTION

●

L o w e r t h e w o r k e q u i p m e n t t o t h e
ground and stop the engine. Operate
the control levers for several times to
release the residual pressure in hydrau-
lic circuits.

●

Open the butterfly nut on the breather
valve and press the relief button to re-
lease pressure in the hydraulic tank.

6-27

Testing and Adjusting

2. Measurement of unloading pressure

1) Start the engine.

2) Measure the hydraulic pressure when

the engine is running at high idle and
all control levers are in a neutral posi-
tion.

NOTE: The hydraulic pressure indicat-
ed is the pressure when the unloading
valve unloads.

3. Measurement of work equipment pres-

sure at relief

1) Start the engine and move the cylinder

to be measured to its stroke end.

2) Measure the hydraulic pressure when

the engine is running at high idle and
the cylinder is in relief condition.

NOTE: The hydraulic pressure indicat-
ed is the pressure when the main relief
valve is in relief condition.

4. Measurement of swing pressure at relief

1) Start the engine. Reach out the work

equipment as far as possible. Lower
the work equipment on the ground in
order to restrict swinging.

2) Measure the hydraulic pressure when

the engine is running at high idle and
the swing circuit is in relief condition.

NOTE: The hydraulic pressure indi-
cated is the pressure when the swing
motor relief valve is in relief condition.

NOTE: The relief pressure of swing
motor is lower than the main relief pres-
sure.

6-28

Testing and Adjusting

NOTE: The boom relief valve cannot be ad-
justed.

ZXT225-1104002

ZXT215-1004004

ZX215-1004029

5. Measurement of travel pressure at relief

1) Start the engine and lock the travel

mechanism.

NOTE: Place the pin (1) between the
sprocket and the track frame to lock the
travel mechanism.

2) Measure the hydraulic pressure when

the engine is running at high idle and
the travel circuit is in relief condition.

NOTE: The hydraulic pressure indicat-
ed is the pressure when the main relief
valve is in relief condition. When the
travel circuit is in relief condition, the
pressure indicated is always the pres-
sure at high relief.

6.11.2 Adjusting

1. Adjustment of main relief pressure

NOTE: If the high relief pressure is abnor-
mal, adjust the high pressure setting of the
main relief valve (3) as per the following.

1) Disconnect the pilot hose.

2) Loosen the locknut (4). Turn the adjust-

ment screw (5) to adjust the pressure.

Pressure rises as the screw turns right.

Pressure drops as the screw turns left.

Each turn of the screw equals about:
12.5 MPa {128 kgf/cm²}

Locknut:

53.5±4.9 N·m {5.5±0.5 kgf·m}

6-29

Testing and Adjusting

3) Check the pressure again after adjust-

ment. Measure the pressure according
to the procedure described above.

●

Connect the pilot hose before measur-
ing the pressure.

●

Adjustment of the high pressure setting
side will affect the low pressure setting
side. The low pressure setting side is,
therefore, to be adjusted too.

2. Adjustment of swing relief pressure

NOTE: If the swing relief pressure is ab-
normal, adjust the swing motor relief valve
(6) as per the following.

ZXT225-1104003

ZX215-1004030

1) Loosen the locknut (7). Turn the adjust-

ment screw (8) to adjust the pressure.

Pressure rises as the screw turns right.

Pressure drops as the screw turns left.

Each turn of the screw equals about:
6.71 MPa { 68.4 kgf/cm²}

Locknut:

78-103 N·m{8.0-10.5 kgf·m}

2) Check the pressure again after adjust-

ment. Measure the pressure according
to the procedure described above.

6-30

Testing and Adjusting

Testing and adjusting tools

Part Number

Part Name

—

21008760

Hydraulic Tester

B210770000084

Adaptor

6.12 Control Circuit Oil Pressure - Test and Adjust

6.12.1 Testing

1. Remove the plug (1) for measuring the hy-

draulic pressure.

2. Install the priming adaptor and connect it

to the hydraulic tester.

Use an oil pressure gauge with a capacity
of 6 MPa{61 kgf/cm²}

3. Start the engine and keep it running until

the hydraulic pressure rises to a point with-
in the operational range.

4. Measure oil pressure when the engine is

running at high idle and all control levers
are in a neutral position.

ZXT215-1004007

CAUTION

●

L o w e r t h e w o r k e q u i p m e n t t o t h e
ground and stop the engine. Operate
the control levers for several times to
release the residual pressure in hydrau-
lic circuits.

●

Open the butterfly nut on the breather
valve and press the relief button to re-
lease pressure in the hydraulic tank.

6-31

Testing and Adjusting

6.12.2 Adjusting

1. If the measurement is less than 3.5 kgf/

cm², loosen the retaining nut (2) and screw
in adjusting stud (3). Watch the change
of readings on the pressure gauge at the
same time. Tighten the retaining nut (2)
when proper pressure value is achieved.

2. Remove all the tools after measurement

and make sure the machine returns to its
normal condition.

ZX215-1004031

6-32

Testing and Adjusting

6.13 Solenoid Valve Output Pressure - Measure

Measuring tools

Part Number

Part Name

—

21008760

Hydraulic Tester

B210770000084

Adaptor

No.

Solenoid Valves to be Measured

Solenoid valve - high/low travel speed

Solenoid valve - swing priority

Solenoid valve - bucket con

uence/dif

ence

Solenoid valve - boom priority

Solenoid valve - pilot lockout

NOTE: Make sure that the initial pressure of
control oil circuit is normal before measuring
the output pressure of solenoid valve.

1. Disconnect the hose of solenoid valve to

measure the pressure at the outlet.

2. Install a tee to location (A) on each sole-

noid valve and connect the hose.

3. Mount the adaptor onto the tee and con-

nect it to the hydraulic tester.

Use a hydraulic tester with a capacity of 6
MPa{61 kgf/cm²} .

CAUTION

●

L o w e r t h e w o r k e q u i p m e n t t o t h e
ground and stop the engine. Operate
the control levers for several times to
release the residual pressure in hydrau-
lic circuits.

●

Open the butterfly nut on the breather
valve and press the relief button to re-
lease pressure in the hydraulic tank.

WXT215-1206001G

6-33

Testing and Adjusting

Table of functioning state - pilot lock solenoid
valve

Functioning State

Function

Lockout control

Lock

OFF

Free

6. Remove all measuring tools after measure-

ment. Make sure that the machine returns
to its normal condition.

Swing priority

Solenoid Valve

Output Pressure

OFF (de-energize)

0 {0}

ON (energize)

3.0~3.9 MPa{30~39 kgf/cm²}

High speed travel

Solenoid Valve

Output Pressure

OFF (de-energize)

0 {0}

ON (energize)

3.9~4.1 MPa{39~41 kgf/cm²}

4. Start the engine and keep it running un-

til the hydraulic oil temperature rises to a
point within the operational range.

5. Run the engine at full speed. Operate the

control levers to open or close each sole-
noid valve, and measure the pressure.

●

The function of each solenoid valve
can be checked through the monitor's
monitoring function. (This is a special
function of the monitor.)

●

When each output pressure reads the
following values, the solenoid valve is
normal.

Testing and Adjusting

Measuring tools

Part Number

Part Name

—

21008760

Hydraulic Tester

B210770000084

Adaptor

NOTE: Make sure that the initial pressure of
control oil circuit is normal before measuring
the output pressure of pilot valve.

No.

Oil Circuit

Measured

No.

Oil Circuit

Measured

Travel left

Bucket DUMP

Travel right

Arm IN

Arm OUT

Swing

Bucket DIG

Boom DOWN

Boom UP

6.14 Pilot Valve Output Pressure - Measure

ZXT225-1104005

1. Remove the pilot pressure switch.

2. Install the adaptor and connect it to the hy-

draulic tester.

Use a hydraulic tester with a capacity of 6
MPa {61kgf/cm²}

3. Start the engine and keep it running un-

til the hydraulic oil temperature rises to a
point within the operational range.

4. Measure the output pressure when the en-

gine is running at high idle and all control
levers of the tested circuit are in neutral
position or at full stroke.

6-35

Testing and Adjusting

Control Lever

Hydraulic Pressure

Neutral

0{0}

Full stroke

Close to the average initial pres-

sure of oil control circuit

(See Table of Standard Values)

5. Remove all measuring tools after measure-

ment. Make sure that the machine returns
to its normal condition.

NOTE: When the measured output pres-
sure reads the following values, the pilot
valve is normal.

6-36

Testing and Adjusting

6.15

Pilot Valves (Work Equipment and Swing) - Adjust

●

If the play of work equipment or swing con-
trol lever is excessive, make adjustment as
per the following procedure.

1. Remove the work equipment and swing pi-

lot valve assembly.

2. Remove the rubber sleeve (1).

3. Loosen the locknut (2). Screw on the disc

(3) until it contacts with the four heads of
plunger (4).

NOTE: Do not move the plunger.

4. When the disc (3) is

xed, tighten the lock-

nut (2) to speci

ed torque.

Locknut:

98~127 N·m {10~13 kgf·m}

5. Install the rubber sleeve (1).

6. Install the work equipment and swing pilot

valve assembly.

ZX215-1004032

6-37

Testing and Adjusting

6.16 Work Equipment Hydraulic Drift - Test

1. Boom and bucket cylinders

1) Park your machine in an attitude as

shown and stop the engine.

NOTE: Load the bucket fully with earth
or impose rated load on the bucket.

2) Operate the control levers so that the

boom is in the raising position and the
bucket in the digging position.

●

If the lowering speed rises, the prob-
lem lies in the cylinder seal. If nothing
changes, the problem lies in the control
valve.

●

Operate the control levers with engine
start switch in the ON position.

●

If the pressure in accumulator drops,
charge the accumulator again by run-
ning the engine for about 10 seconds.

2. Arm cylinder

ZX215-1004033

NOTE: If hydraulic drift exists in the work
equipment cylinder, check it according to the
following procedure and determine whether
the failure lies in the cylinder seal or in the
control valve.

Testing and Adjusting

1) Park your machine in an attitude as

shown. The distance between the arm
cylinder and the digging stroke end is
100 mm. Stop the engine.

2) Operate the control levers in order to

place the arm in the digging position.

●

If the lowering speed rises, it is failure
of the cylinder seal. If nothing changes,
it is failure of the control valve.

●

Operate the control levers with engine
start switch in the ON position.

●

If the pressure in accumulator drops,
charge the accumulator again by run-
ning the engine for about 10 seconds.

[Reference]

If hydraulic drift is caused by failure of the
cylinder seal, the reason for lowering speed
increase during the above operation is de-
scribed below:

1) If the machine is set in the above position

(where the holding pressure is applied to
the bottom side), the oil leaks from the bot-
tom side to the head side. The pressure in
the head side is increased.

2) As the pressure in the head side de-

creases, the pressure in the bottom side
increases in order to keep it balanced.
This process is repeated until balance is
reached at a certain level depending on
the amount of leakage.

3) When the pressure is balanced, the lower-

ing speed decreases. If the control levers
are operated according to the above proce-
dure, the oil circuit in the head side opens
to the drain circuit (while the bottom side is

ZX215-1004034

6-39

Testing and Adjusting

closed by a check valve), and the oil

ows

to the drain circuit from the head side. As a
result, the lowering speed increases.

3. Checking the pilot valve

While the pressure in the accumulator is
high, set the hydraulic lockout control in
the LOCKED/FREE position and measure
the hydraulic drift respectively.

●

Operate the control levers with engine
start switch in the ON position.

●

If the pressure in accumulator drops,
charge the accumulator again by run-
ning the engine for about 10 seconds.

●

If there is a difference in hydraulic drift
between the LOCKED position and the
FREE position, it the failure (internal
fault) of the pilot valve.

SANY Crawler Hydraulic Excavator SY195C9, SY205C9, SY215C9, SY225C9. Service Manual - page 22