Forklifts are essential equipment in logistics, warehousing, and loading and unloading operations. As core equipment in modern logistics and production, their stable operation is directly related to operational efficiency and personnel safety. Their working environment often involves high loads, high frequency, and complex operations, so the risk of failure is not low.
However, like any mechanical equipment, forklifts are subject to various types of failures. Mastering common troubleshooting methods and establishing sound daily maintenance habits are key measures to minimize downtime, extend equipment life, and ensure operational safety. Promptly identifying common faults, correctly troubleshooting the causes, and performing routine maintenance are key to ensuring efficient and safe operation and extending the service life of forklifts. This article, based on industry information, summarizes common forklift fault types, troubleshooting methods, and daily maintenance key points for forklift managers and maintenance personnel for reference.
Forklift faults typically occur in core components such as the powertrain, hydraulic system, electrical system, transmission and steering system, and mast lifting mechanism. The following is a breakdown by fault category. Each category begins with a description of the symptoms and possible causes, followed by specific troubleshooting steps.
1.1 Starting/Failure to Start
Symptoms: No response after turning the forklift key or pressing the start button, difficulty starting, stalling after starting, speed fluctuations, etc.
Possible causes: Low battery or poor contact, fuel/gas supply issues (internal combustion forklifts), safety switch not in place, clogged fuel filter, starting system malfunction, etc.
Troubleshooting Methods:
①. Check the battery (electric forklifts) or starting power source (internal combustion forklifts) for sufficient power and for loose or corroded terminals.
②. Confirm that the operator's safety pedal, seat switch, and gear lever are in "neutral" or meet starting requirements.
③. For internal combustion forklifts, check for sufficient fuel, a clogged fuel filter, and severe air filter obstruction.
④. Check the cooling system (such as water cooling) for proper function and the radiator for dust accumulation or obstruction.
⑤. If the above simple checks fail, the starter, ignition system, or control module may be faulty. Contact a professional for repair.
1.2 Lift/Tilt Function Malfunction or Abnormality
Symptoms: The forks fail to raise or lower, raise or lower slowly, tilt motion is sluggish or erratic, unusual noises are heard, or the cylinder leaks oil.
Possible Causes: Low or contaminated hydraulic oil, clogged hydraulic filter, leaking hydraulic lines or seals, worn lift chains or guide rails, or damaged tilt system components.
Troubleshooting Methods:
①. With the forks in the lowest position, check that the hydraulic oil tank level is within the marked range.
②. Check that the hydraulic oil is milky white, turbid, or contains impurities. Replace if necessary.
③. Inspect the oil pipes and connectors for leaks, stains, or damage.
④. Inspect the lift chain, hook, and roller guide rails for stretching, breakage, deformation, or severe wear.
⑤. Observe whether there is any "stuck" or "jumpy" movement during the lift. Disassemble and inspect the cylinder or seals if necessary.
⑥. If the tilt function is abnormal, focus on inspecting the tilt cylinder and its connecting components (bushings, hinges) for looseness or damage.
1.3 Poor Steering/Handling
Symptoms: Slow steering wheel or handle rotation, directional deviation, unusual noise during steering, loose, slipping, or sticking steering feel.
Possible Causes: Low or deteriorated power steering fluid level, worn steering linkage (gears, bearings, tie rods), abnormal tire pressure, steering cylinder or pump failure.
Troubleshooting Methods:
①. Check tire pressure for compliance. Low rear tire (or steering wheel) pressure can cause handling problems.
②. Check the power steering fluid (if equipped) for a normal level, darker color, and contamination.
③. Inspect the steering tie rod, ball joint, and bearings for looseness, wear, or rust.
④. While the vehicle is starting, gently steer the steering wheel to feel for smoothness and noise. If there is a rattling or clicking sound, disassemble the steering pump or cylinder.
⑤. If the problem persists, have the steering system thoroughly inspected by a professional.
1.4 Degraded Braking System Performance
Symptoms: A soft brake pedal feel, slow brake response, continued rolling after releasing the brakes after stopping, extended stopping distance, and unusual braking noise.
Possible Causes: Low brake fluid level, severe wear on the brake pads or discs, leaking seals in the master or slave cylinders, air in the brake lines, improper adjustment of the parking brake or parking brake.
Troubleshooting Methods:
①. Check the brake fluid (hydraulic brake system) level and quality. If the fluid is dark or contains impurities, replace it immediately.
②. Check the brake pads and discs for wear. The brake pad thickness should be within the specified range.
③. Check the brake lines and joints for oil leaks. Severe leaks may require seal replacement.
④. If the brake pedal feels spongy or has no effect even when fully depressed, bleed the brake system.
⑤. Check the parking brake mechanism and rigging for looseness and proper adjustment.
⑥. After each brake system repair, perform a low-speed test run to check brake performance.
1.5 Engine/Motor Overheating or Smoking
Symptoms: Abnormally high temperature during operation, smoke under the hood, a burning odor detected by the operator, or a clogged heat sink.
Possible Causes: Radiator blockage, damaged water pump or fan, insufficient coolant, severely dirty air filter, hydraulic system overload, engine lubrication system malfunction, or oil line blockage.
Troubleshooting Methods:
①. Check the radiator (or cooling system) for dust, blockage, or damage, and remove any debris.
②. Check the coolant level for normal operation and leaks.
③. Check the water pump and fan for proper operation; check the fan belt for looseness or breakage.
④. Check the air filter for severe obstruction; if so, clean or replace it immediately.
⑤. Check the engine oil for discoloration and abnormal viscosity. If abnormal, this could indicate frictional overheating due to poor lubrication.
⑥. If the cooling system is functioning properly but the vehicle is still overheating, check the engine for mechanical wear or oil deficiency.
1.6 Electrical System/Safety Device Malfunction
Symptoms: Instrument warning lights illuminate, control panel malfunctions, lights/horn inoperative, seat belt switch inoperative, cable corrosion, or blown fuse.
Possible Causes: Deterioration of switches or relays, loose terminals, worn, corroded, or broken wiring harnesses, frequently blowing fuses, or poor battery connection.
Troubleshooting Methods:
⑤. Check all safety-related switches for proper operation (such as the seat switch, parking brake switch, and seat belt detection switch).
②. Check the battery terminals for tightness and corrosion. Clean and apply preservative immediately.
③. Check the electrical wiring harness for damage, wire sheathing for signs of age, cracks, or wear.
④. Check the fuses in the fuse box to determine the cause of frequent blowing.
⑤. Check the lights, horn, warning lights, and reverse buzzer for proper operation to ensure safety devices are effective.
⑥. Save maintenance records for future analysis of fault trends.
1.7 Tire and Travel System Abnormalities
Symptoms: Excessive tire wear, uneven tire pressure, noticeable vehicle vibration when shifting a load, vehicle tilt, or unstable handling.
Possible Causes: Incorrect tire pressure, tire damage or cracks, rim deformation, damage to the load wheel or front/rear axle, uneven ground, or damage to the suspension or structure.
Troubleshooting Methods:
①. Regularly check tire pressure, tread depth, and for bulges, cracks, or external damage.
②. Check the rim for deformation, loose nuts, and unusual bearing noise.
③. Check the front and rear axles for any abnormal looseness or noise.
④. If you feel any vibration or tilt during operation, stop the machine immediately and check the load, ground conditions, and suspension system.
⑤. For vehicles frequently operated on rough or uneven surfaces, more frequent inspections are recommended.
Scientific and standardized daily maintenance is the most effective way to reduce failures, ensure safety, and extend the life of your forklift. Based on the troubleshooting described above, the following provides professional advice on forklift maintenance from both a daily and regular perspective.
2.1 Daily/Pre-shift Inspection (Operator's Perspective)
Operators should perform a pre-inspection before their daily shift to identify any abnormalities. Specific items to consider include:
Check tire pressure and external damage.
Check fluid levels (hydraulic oil, water/coolant, engine oil, brake fluid) for normal operation.
Inspect the forks, boom, and lifting mechanism for any bends, cracks, or deformation.
Check cab safety devices: seat belts, warning lights, horn, rearview mirrors, and reverse buzzer for proper function.
Run a test run: Check for proper functioning of brakes, steering, lift, tilt, and other functions.
Inspect the floor for oil stains or signs of fluid leakage.
Operators should note any abnormalities and report them immediately to avoid operating the vehicle while it is faulty.
2.2 Regular Maintenance (from the Maintenance Personnel/Manager's Perspective)
It is recommended to establish a maintenance plan (based on operating hours or calendar) and strictly adhere to it. Key maintenance items include:
At regular intervals (e.g., every 250 hours or every 6 weeks), perform the following: oil change, filter replacement, fastener inspection, chain lubrication, hydraulic system leak detection, and cooling system cleaning.
Perform a comprehensive inspection annually or every 2,000 operating hours: including engine/motor performance testing, steering system structural component inspection, brake system deep inspection, cab structure and safety device inspection, and a thorough review of the track/travel system.
Hydraulic oil and power steering fluid should be of high quality, not just fluid level. Contaminated oil can accelerate component wear.
Keep the battery (electric forklifts) or starting power source (internal combustion forklifts) clean, the terminals free of corrosion, regularly refill with water (if applicable), and the charging system in working order.
Keep the radiator/cooling system clean, remove dust and debris promptly, and ensure proper air circulation.
Regulate maintenance records: All maintenance, faults, repairs, and parts replacements should be recorded to facilitate trend analysis and management optimization.
Operator training and standardized equipment operation: Proper operation can significantly reduce maintenance costs and extend service life.
2.3 Maintenance Recommendations for Special Environments/Load Scenarios
If the forklift is used in dusty, humid, or chemically corrosive environments, the inspection interval should be shortened, and cleaning and maintenance should be strengthened.
If the forklift is operated under heavy loads, frequently, or in high-temperature and high-humidity environments, it is important to monitor the hydraulic oil temperature, cooling system efficiency, and structural component fatigue.
If the forklift is used at night or in a cold storage environment (low temperatures), additional attention should be paid to battery performance, hydraulic system viscosity, and starting reliability.
When used on uneven surfaces or in areas with numerous obstacles, the travel system, tires, and suspension should be inspected more frequently.
Before performing maintenance:
Always park the forklift, apply the parking brake, shut off the engine/disconnect the main power supply, and remove the key.
Before operating the hydraulic system, such as the lifting or tilting system, ensure that the forks are lowered to their lowest position or that they are securely supported (e.g., using a dedicated stand). Never perform maintenance solely relying on the hydraulic system to support a load.
Wear appropriate personal protective equipment (gloves, goggles, safety shoes, etc.).
When performing maintenance:
Use the correct tools and follow proper procedures.
When working on the hydraulic system, release internal pressure (slowly loosen the connector).
When handling the battery, be careful to prevent short circuits (remove the negative terminal first, then the positive terminal; the reverse is true when installing).
Keep the work area clean, well-ventilated, and well-lit.
Troubleshooting: If you encounter unresolvable faults or issues involving control systems or safety devices, be sure to contact a professional forklift repair service provider. Never blindly disassemble the equipment.
As the workhorse of warehousing and logistics, the stability, safety, and reliability of forklifts are paramount. By systematically understanding common fault types, establishing a clear troubleshooting process, and implementing standardized daily and scheduled maintenance procedures, you can effectively reduce unexpected failures, extend equipment life, improve operational efficiency, and ensure operational safety.
The efficient and safe operation of a forklift is no accident; it relies on the operator's proper use, management's oversight, rigorous daily maintenance, and timely and accurate troubleshooting. By incorporating the knowledge and requirements in this guide into your daily workflow, establishing a comprehensive preventive maintenance plan (PMP), and strictly adhering to safety regulations, you can significantly reduce equipment failure rates, minimize unplanned downtime and repair costs, and safeguard the lives of your operators. In the forklift industry, every penny invested in preventive maintenance will translate into multiple returns in safety and operational benefits. Proper operation is the foundation of safety, and meticulous maintenance is the foundation of efficiency!
Through the above introduction to common forklift troubleshooting and daily maintenance, I believe you have a clearer understanding of forklifts. If you still have any questions or want to purchase forklifts and accessories, please contact us.
