Terex RT500-1 - Boom Hoist Circuit

Boom Hoist Circuit
CONDITION CAUSE REMEDY
BOOM DRIFTS DOWN Hold valve not seating
properly
Replace hold valve
Hoist cylinder by-passing See section on “Cylinder
Leakage”.
BOOM HOIST ONLY -
INOPERATIVE OR ERRATIC
Boom will drift down Repair or replace hold valve
Boom won’t lower Repair, replace, or backflush
hold valve
Boom hoist cylinder binding Repair or replace
Load is too great Consult capacity chart,
check RCI
Piston packings damaged Replace packings
Low oil level Add oil as required
Hose plugged or liner
collapsed
Replace hose
Air in cylinder Bleed cylinder
BOOM DROPS SLIGHTLY
AS RAISE CONTROL IS
RELEASED
Air in cylinder Bleed cylinder
Boom hoist hold valve free
flow check not seating
properly
Replace hold valve
BOOM HOIST AND
TELESCOPE INOPERATIVE
OR ERR
Pump disconnect not
engaged
Engage pump disconnect
Main relief valve
malfunctioning
See section on “Relief
Valves”.
Low oil level Add oil as required
Rotary manifold leaking
internally
Reset rotary manifold
Tandem pump faulty See section on “Pumps”
217REVISED: