Common faults and solutions for excavator

It is inevitable for excavators to encounter various faults during long-term high-intensity operations. The following are some common faults and corresponding solutions to help quickly troubleshoot and handle problems:

I. Engine-related Faults

1. Difficulty in starting or failure to start the engine
   Common causes:

• Fuel supply issues (insufficient fuel, blocked fuel lines, clogged fuel filters);
• Insufficient battery power, loose or oxidized battery terminals;
• Faults in the starter motor (such as worn carbon brushes, poor line contact);
• Faults in the diesel pump or fuel injectors.

• Check the fuel quantity, clean or replace the fuel filter, and unclog the fuel lines;
• Measure the battery voltage. If it is lower than 12V, charge it, polish the terminals and fasten them;
• Check the starter motor lines and replace worn carbon brushes;
• If there is a suspicion of problems with the diesel pump or fuel injectors, professional personnel are required for inspection and debugging.

2. Insufficient engine power
   Common causes:

• Clogged air filter, resulting in insufficient air intake;
• Poor fuel supply in the fuel system (such as poor atomization of fuel injectors, insufficient pressure of the fuel pump);
• Turbocharger faults (such as damaged impellers, air leakage);
• Insufficient engine cylinder pressure (poor valve sealing, worn piston rings).

• Clean or replace the air filter;
• Inspect the fuel system, clean the fuel injectors, and replace them if necessary;
• Overhaul the turbocharger and replace damaged components;
• Test the cylinder pressure, repair the valves or replace the piston rings.

II. Hydraulic System Faults

1. Hydraulic oil leakage
   Common causes:

• Loose hydraulic line joints or aging/damaged seals;
• Wear of the hydraulic cylinder barrel and piston rod, leading to poor sealing;
• Damage to the housing of components such as hydraulic pumps and hydraulic motors.

• Fasten loose joints and replace aging seals;
• Check the wear condition of the cylinder. Minor wear can be repaired; if severe, the cylinder needs to be replaced;
• Replace damaged hydraulic components to avoid further faults caused by continued use.

2. Insufficient pressure in the hydraulic system
   Common causes:

• Wear of the hydraulic pump, resulting in reduced volumetric efficiency;
• Relief valve faults (sticking, excessively low set pressure);
• Insufficient hydraulic oil or inappropriate viscosity;
• Blocked or leaking hydraulic lines.

• Overhaul or replace the hydraulic pump;
• Clean the relief valve and readjust the pressure to the specified value;
• Replenish or replace hydraulic oil that meets the specifications;
• Unclog blocked lines and repair leakage points.

3. Slow/weak movement of the boom, arm, or bucket
   Common causes:

• Sticking or wear of the control valve corresponding to the cylinder;
• Internal leakage of the cylinder (damaged piston seals);
• Insufficient hydraulic oil flow (such as hydraulic pump faults, blocked lines).

• Dismantle and clean the control valve, replace it if severely worn;
• Replace the seals in the cylinder;
• Inspect the hydraulic pump and lines to ensure normal flow.

III. Travel System Faults

1. Travel deviation
   Common causes:

• Inconsistent rotation speeds of the travel motors on both sides (such as wear of one motor, improper displacement adjustment);
• Faults in the travel control valve (sticking of the valve core, leading to uneven oil supply on both sides);
• Inconsistent tightness of the crawlers or foreign objects stuck in the crawler plates.

• Adjust the displacement of the travel motors, replace them if severely worn;
• Clean or replace the travel control valve;
• Adjust the tightness of the crawlers and remove foreign objects from the crawlers.

2. Weak travel
   Common causes:

• Travel motor faults (such as internal leakage, gear wear);
• Damaged gears in the travel reducer or insufficient lubricating oil;
• Insufficient oil supply pressure from the hydraulic system to the travel motors.

• Overhaul or replace the travel motors;
• Inspect the reducer gears, replenish or replace the lubricating oil;
• Inspect the hydraulic system to ensure normal pressure in the travel oil circuit.

IV. Electrical System Faults

1. Dashboard alarm or abnormal display
   Common causes:

• Sensor faults (such as water temperature, oil pressure, liquid level sensors);
• Poor line contact or short circuit;
• Damage to the dashboard itself.

• Test the sensors and replace damaged ones;
• Check line connectors and repair short circuits or loose points;
• Replace the faulty dashboard.

2. Malfunction of accessories such as lights and horns
   Common causes:

• Blown fuse;
• Damaged switch;
• Line open circuit.

• Replace the fuse of the corresponding specification;
• Inspect and replace damaged switches;
• Inspect the lines and repair open circuit points.

V. Other Common Faults

1. Weak bucket digging force
   Common causes:

• Damaged seals of the bucket cylinder, leading to internal leakage;
• Sticking of the bucket control valve;
• Insufficient hydraulic oil pressure.

• Replace the cylinder seals;
• Clean the control valve;
• Adjust the hydraulic system pressure to the specified value.

2. Abnormal noise (from engine, hydraulic system, or structural components)
   Common causes:

• Engine abnormal noise: bearing wear, excessive valve clearance, timing gear faults;
• Hydraulic system abnormal noise: hydraulic pump cavitation (low oil level, air leakage in the suction line), wear of hydraulic components;
• Structural component abnormal noise: loose connections, worn pins.

• For engine abnormal noise, disassemble and inspect, replace worn parts, and adjust valve clearance;
• For hydraulic system abnormal noise, replenish hydraulic oil, repair air leakage in the suction line, and replace worn components;
• Fasten loose connections, replace worn pins, and apply grease.

Notes