Common rubber tired crane crane malfunctions and emergency solutions?

Common faults in RTG (Roller-Tracked Toy) cranes are concentrated in five major systems: hydraulic, traveling/steering, hoisting/luffing, electrical, and tires/outriggers. Emergency handling follows the principle of first stopping the machine to avoid danger, then investigating the root cause, and finally restoring safety. Below are high-frequency faults and on-site emergency plans:

I. Hydraulic System Faults (Most common, affecting all movements)

1. Weak movement, slow speed, high oil temperature

Symptoms: Slow hoisting/luffing/slewing/traveling, load drop, oil temperature exceeding 60℃ alarm

Causes: Oil contamination, filter blockage, internal leakage in the hydraulic pump, low relief valve pressure, cooling failure

Emergency: Immediately stop the machine and switch to no-load/light-load to avoid pressure buildup under heavy load.

Check oil level and temperature; replace/clean the return oil filter.

Temporarily lower the relief valve pressure (emergency only, recalibrate afterward).

Clean the cooler to restore heat dissipation; for severe internal leakage, stop the machine and inspect the pump/valve.

2. Hydraulic oil leakage (pipe joints/cylinders/ (Sealing)

Phenomena: Oil leakage on the ground, pressure drop, shaking operation

Emergency: Immediately shut off the main hydraulic valve/power, do not operate under pressure
Clean with an oil-absorbing cloth, set up anti-slip warnings
Loose joints: Tighten after stopping the machine; Damaged seals: Temporarily seal with plugs, replace seals
Internal leakage in cylinders/rod damage: Mark the location, do not load heavily, await professional repair

3. Cylinder sinking (luffing/outriggers/lifting)

Phenomena: Boom drops automatically, outriggers become weak, load slips

Causes: Balance valve stuck, internal leakage in cylinders, lock failure

Emergency: Immediately lower the load, retract the boom to a safe angle
Clean/tap the balance valve body (temporarily unblock); replace the failed seal
Outrigger sinking: Immediately retract the outriggers, move to solid ground, do not continue operation

II. Travel and steering system failures

1. Travel deviation, lack of power, abnormal noise ("clunking/...") "Woo-woo!"

Causes: Uneven tire pressure, drive motor oil leak, gearbox wear, loose suspension
Emergency: Check and unify tire pressure (0.2–0.3 MPa higher under heavy load than unload)
Clean tires of foreign objects; drive motor oil leak: stop the machine and replace the seal
Severe abnormal noise: Do not drive at high speed, move to the repair area at low speed

2. Heavy steering, not returning to center, stuck

Causes: Low steering pump pressure, insufficient oil in ball joint/tie rod, stuck hydraulic valve
Emergency: Lubricate steering ball joint and tie rod joint
Check steering hydraulic oil level and filter; clean steering valve
Severe stuck: Do not force steering to avoid damaging the steering mechanism

3. Brake failure/drag (driving/parking)

Symptoms: Long braking distance, pulling to one side, brake lock-up
Emergency: Immediately stop the machine at low speed, engage the handbrake + use a chock box
Check brake pad wear and brake fluid level; replace brake pads/brake fluid
Stuck brake caliper: lubricate/ Replace the pump; Driving with defects is strictly prohibited.

III. Lifting, Luffing, and Slewing Mechanism Failures

1. Lifting hook slippage, lack of power, abnormal noise ("clicking")

Causes: Excessive brake clearance, worn brake pads, drum/pulley slippage, broken wire rope

Emergency: Immediately stop lifting, slowly lower the load, do not hover in the air.

Adjust brake clearance to 0.2–0.5mm, grind/replace brake pads.

Wire rope slippage: Stop and reset, check pulley wear; excessive broken wires: replace immediately.

2. Luffing vibration, sinking, inability to lock

Emergency: Retract the boom to the minimum amplitude, do not luff with heavy load.

Clean/replace the balance valve; inspect for internal leakage in the cylinder, replace the seal.

Severe vibration: Check the luffing pulley and wire rope, eliminate jamming.

3. Slewing jamming, abnormal noise, misalignment

Causes: Insufficient lubrication in the slewing bearing, gear wear, hydraulic motor malfunction

Emergency: Add slewing bearing grease (lithium-based grease)

Clean foreign objects from the gear surface; Severe abnormal noise: Do not slewing, inspect the motor/gear

IV. Tire and outrigger malfunctions (directly related to rollover risk)

1. Tire detachment, bulge, leak

Emergency (detachment)

Immediately stop the machine, engage the handbrake, move to a safe area, and set up warning signs

Strictly prohibit forced driving/steering to prevent tire blowout and rollover

Check for rim deformation and loose bearings; detachment/bulge: replace the tire immediately

Daily maintenance: Maintain standard tire pressure, avoid uneven loading, and promptly remove stones

2. Outriggers cannot extend/retract, sinking

Emergency: Switch to manual emergency pump and attempt to extend and retract the outriggers

Clean the solenoid valve and lubricate the slider; Internal leakage in the cylinder: replace the seal

Outriggers cannot support: Do not lift, move to a safe location

V. Electrical system malfunctions

1. Controller unresponsive, alarm, sensor malfunction

Symptoms: No operation, abnormal weight/angle display, false triggering of safety protection

Emergency: Check main power supply, fuse, emergency stop button; reset controller

Loose sensor wiring: tighten again; ineffective calibration: replace sensor

Communication failure (CAN bus): reconnect and unplug connectors, check for wiring damage

2. Sudden power outage (during operation)

Emergency: Remain calm, do not force operation

Activate emergency pump/manual release, slowly lower the load

Secure equipment, set warning signs, wait for power restoration or professional rescue

VI. General Emergency Handling Procedure (applicable to all faults)
Immediate shutdown: cut off power, engage handbrake, lower load / Retract the boom.
Safety isolation: Set up warning signs and prohibit unauthorized personnel from entering the working radius.
Preliminary investigation: Observe the phenomenon, listen for abnormal noises, check for leaks, and check alarm codes.
Emergency recovery: Handle according to the above plan; if the problem cannot be resolved, operation with the fault is strictly prohibited.
Reporting and recording: Report the fault, fill out the maintenance record, and arrange professional repair.
VII. Key prevention points
Pre-shift inspection: Tire pressure, hydraulic oil level, wire rope, brakes, outriggers, safety devices.
Regular maintenance: Hydraulic oil/filter replacement, lubrication, brake testing, sensor calibration.
Overloading, uneven loading, sudden stops and starts are strictly prohibited; avoid impact loads.