New Holland LS140 Workshop Manual page 280

PROBLEM
Noisy system pump
Hydraulic reservoir oil foaming/
milky
Low system pump oil flow, under
pressure
No system pressure
Boom and bucket will not function
SECTION 35 - HYDRAULIC SYSTEM
POSSIBLE CAUSE
Oil level too low
Oil of incorrect viscosity
Suction line plugged
Reservoir air vent plugged
Air leaks at pump inlet line fittings
Air or water in system
Plugged inlet line
Low oil level in reservoir
Air leaks at pump inlet line and fit-
tings
Worn pump body.
Inoperative relief valve
Plugged inlet line
Worn hydraulic pump
Pump shaft broken
Internal leakage in control valve or
cylinders
Service/Run switch in the service
position
Boom and bucket solenoids mal-
functioning
Pump shaft broken
35-11
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CORRECTION
Add proper oil and amount
Replace oil and filter
Clean or replace line
Clean reservoir cap
Tighten or replace line and fittings
Check for air leak in hydrostatic
pump case drain line from hydro-
static pumps to section side of gear
pump
Check for air leak on suction side of
pump and check reservoir fill neck
for leak to allow water to enter sys-
tem
Check for air leak in hydrostatic
pump case drain line from hydro-
static pumps to section side of gear
pump
Clean or replace line
Add proper oil and amount
Tighten or replace line and fittings
Check for air leak in hydrostatic
pump case drain line from hydro-
static pumps to section side of gear
pump
Replace body if ID of body exceeds
acceptable limits. Refer to service
manual.
Replace valve
Clean or replace inlet line
Rebuild or replace pump
Replace relief valve and replace or
repair pump
Rebuild components
Put Service/Run switch in the run
position
Check solenoid operation
Replace relief valve and replace or
repair pump