Terex RT500-1 - Boom Telescope Circuit

Boom Telescope Circuit
CONDITION CAUSE REMEDY
TELESCOPE FUNCTION
ONLY - WILL NOT OPERATE
Load too great Tilt boom pedal only halfway
forward, not all the way
forward (“high speed”) .
Reduce load or set boom
length before lifting load.
Both port relief valves sticking See section on “Relief
Valves”.
Hose plugged or liner
collapsed
Replace hose
BOOM EXTENSION JERKY
OR ERRATIC
Inadequate grease on boom
pad surfaces
Lubricate boom where pads
contact boom
Wear pads damaged Replace wear pads
Wear pads shimmed to
boom too tight
Reshim wear pads
Faulty counter balance valve Replace counter balance
valve
Loose chain system Adjust chains as required
TELESCOPE CYLINDER
EXTENDS BUT WILL NOT
RETRACT
Port relief valve sticking See section on “Relief Valves”
Hold valve malfunctioning Repair or replace
Internal leakage in cylinder See section on “Cylinder
Leakage”
Extend valve malfunctioning Repair or replace
BOOM SECTIONS RETRACT
UNDER LOAD
“O” ring around hold valve
damaged
Replace “O” rings
Hold valve not seating
properly
Repair or replace
Telescope cylinder by-
passing
See section on “Cylinder
Leakage”
RT500
Troubleshooting
218 REVISED: