Bosch Rexroth SM 12 - 3 Troubleshooting

Troubleshooting3
CAUTION
BEFORE STARTING ANY PROCEDURES OF TROUBLE SHOOTING OR REMOVING THE CONTROL BLOCK,
INSPECT THE GLOBAL MACHINE’S HYDRAULIC SYSTEM TO ELIMINATE ALL POSSIBLE MALFUNCTIONS NOT
RELATED TO THE SM 12 CONTROL BLOCK.
Abnormal operation of the actuators connected to the control blockTableau 2:
Malfunction Probable cause Additional Checks Remedy
Lack of strength at all
actuators
1 - Primary pressure relief valve
defective
Take a pressure measurement
(see block specifications)
Replace primary pressure relief valve
(see § 6.1)
2 - Primary pressure relief valve
out of adjustment
Make necessary adjustments
(see § 5.4)
Lack of force on one
actuator only
1 - Secondary pressure relief
valve out of adjustment
Reset to original pressure (refer to
block specifications).
2 - Secondary pressure relief
valve blocked "open"
(return to tank)
Replace secondary pressure relief
valve (see § 7.1)
Movement performance
slow
Spool stroke incorrect Manual control: measure spool
stroke (see § 7.3)
If stroke is incorrect: replace the
distribution element (see § 8)
Lack of load hold at work Load hold check valve failure Replace check valve or distribution
element (see § 8 and 7.9)
Lack of load hold at
neutral position or relief
valve internal leak
Excessive clearance between the
housing and the spool or relief
valve internal leak
Replace the distribution element (see
§ 8) or secondary pressure relief
valve (see § 7.1)
Abnormal control block operationTableau 3:
Malfunction Probable cause Additional Checks Remedy
Detent malfunction Mechanism defective Replace mechanical detent
(see § 7.4)
Defective manual
operation type R5: no
movement
Ball joint broken Replace the operation (cf. § 7.6)
Defective manual
operation type M1 : lever
stiff
1 - Nut overtightened Adjust tightening torque (cf. § 7.5)
2 - System defective Replace the operation (cf. § 7.5)
Increase of force on
controls or spool return
defective
Control block assembly tie rods
too tight
Check tightening torque Loosen and tighten
to 18 ± 10% N.m.
CAUTION
REMOVE CONTROL BLOCK
FROM ITS FIXATION POINTS
Spool seals obsolete Replace spool seals (see § 7.2)
6/30 Bosch Rexroth AG Type SM 12 | RE 64122-S/06.2011
Troubleshooting