SANY LATIN AMERICA
7-103
SY195/205/215/225C9 Crawler Hydraulic Excavator
Troubleshooting
Shop Manual - June 2013
H-7 Arm speed slow
Trouble
●
The arm moves slowly.
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
1
Malfunction of left pilot
valve (arm circuit)
●
Stop the engine. Perform troubleshooting while the engine is
running at high idle.
Arm control lever
Pilot valve output pressure
"NEUTRAL"
0 {0}
Arm IN or Arm OUT
≥
3.5MPa
{36 kg/cm²}
2 Failure of pressure sensor
●
Stop the engine. Perform troubleshooting while the engine is
running at high idle.
Check the pressure sensor by replacing it with a new one.
3
Malfunction of arm control
valve (spool)
Spool of arm control valve may have malfunction. Check it directly.
4
Malfunction of arm control
valve (regeneration valve)
Regeneration valve of arm control valve may have malfunction.
Check it directly.
5
Malfunction or defective
seal of arm control valve
(Relief valve and makeup
valve)
The relief valve or makeup valve inside the arm control valve may
have malfunction or defective seal. Check the valves directly.
6
Failure of arm cylinder
●
Stop the engine. Perform troubleshooting while the engine is
running at high idle.
Cut off the oil passage to the high-pressure side of the cylinder.
Disconnect the cylinder from the main valve. Measure the displace-
ment of piston for 15 minutes after the cylinder becomes stable. If
the measured value is greater than 10 mm, it is deemed that cyl-
inder has a defective seal. For more information on the measuring
procedure refer to "Testing and Adjusting", "Hydraulic Drift (Work
Equipment) - Test".
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