MSD 7R SHEARS
Rotator Maintenance Section 7 Page 7
SYMPTOM PROBABLE CAUSE REMEDY
1. Shear will not rotate a. Operating fl ow is too low
b. Crossover relief valve is bypassing oil
c. Operating pressure is too low
d. System hydraulic fl uid temperature
excessively high
e. Broken output shaft drive
f. Internal leakage in manifold block on
motor
g. Excessive wear on motor rotating
components
h. Internal leakage in valve supplying oil
i. Valve supplying hydraulic fl ow is faulty
i. Flow control valve needs adjustment
ii. Check supply fl ow
i. Replace crossover relief valve
i. Check crossover relief valve
ii. Check supply pressure
i. Check base machine hydraulic system
i. Replace or rebuild the hydraulic motor
i. Replace manifold block on motor
ii. Check cartridge valve seals for damage
i. Replace or reseal the hydraulic motor
ii. To check, remove the case drain line and measure
the amount of fl ow out of the case
i. Check base machine hydraulic system
i. Check base machine hydraulic system
2. Rotation is excessively
slow
a. Operating pressure is too low
b. Crossover relief valve bypassing oil
c. Operating fl ow is too low
i. Replace crossover relief valve to increase the pres-
sure
i. Replace crossover relief valve
i. Adjust fl ow control to increase fl ow to rotation
group
ROTATION CIRCUIT TROUBLESHOOTING GUIDE
The information contained in this guide provides for troubleshooting the LaBounty shear only. Any reference to the
excavator will be made only to give some guidance as to where a problem may exist. Any specifi c maintenance and
troubleshooting information will need to be provided by the original equipment manufacturer of the excavator or the
authorized dealer.
