Bush Hog BH850 Lawn Mower User Manual


 
19
Troubleshooting (Continued)
Problem Cause Correction
Loss of power in any one Worn or damaged rod seals on Repack cylinder. Rebuild cylinder,
cylinder, including lift cylinder; external leaks replacing damaged parts as necessary.
and crowd
Spool not moved to full stroke Check spool travel - should be .26”
either way, or a total of .52”.
Overload relief valve in the control Clean relief carefully but do not disturb
valve stuck open or malfunctioning its pressure setting as it cannot be field
calibrated, or replace cartridge.
Worn control valve Replace the control valve.
Loss of power in swing Loose oil line connections, Tighten all hose connections and
cylinders, but other leaks in line or broken lines replace any damaged O-rings at
cylinders functioning leaking O-ring fittings. Check and
properly. replace any damaged hoses and lines.
Restrictions in oil lines Check and replace any damaged hoses
and lines. Check for pinched hoses.
Oil is bypassing cylinder piston, Replace or rebuild the cylinder; replace
scored piston, worn piston damaged parts.
packing, or defective piston
assembly
Scored piston rods and worn Replace or rebuild the cylinder; replace
guides in cylinder damaged parts.
Bent piston rod in cylinder Replace or rebuild the cylinder; replace
damaged parts.
Worn or damaged rod seals on Repack cylinder. Rebuild cylinder,
cylinder; external leaks replacing damaged parts as necessary.
Spool not moved to full stroke Check spool travel - should be .26”
either way, or a total of .52”.
Relief valve setting in backhoe Relief pressure will have to be checked
control valve too low or defective and corrections made. Backhoe
system pressure is 2400 PSI. Relief
valve may need cleaning and over
hauling, or entire cartridge must be
replaced.
Worn control valve Replace the control valve.
Maximum swing action Bent piston rod in cylinder Replace or rebuild the cylinder; replace
cannot be obtained damaged parts.
Something jamming the swing Remove interference.
linkage
Slow operation of machine
(lack of power) all cylinders Low oil supply in reservoir Fill to proper level.
Oil viscosity too heavy, or oil Use recommended hydraulic fluid. Run
is not at operating temperature machine until oil reaches operating
temperature.
Insufficient pumping Advance engine throttle.
Diverter valve on prime mover Diverter valve may need rebuilding or
leaking externally or bypassing replacing.
oil internally through valve to
reservoir
Excessive back pressure Relieve condition. Restriction may be
from outlet to reservoir.