Common Fault Analysis and Improvement Suggestions for Forklifts

1、 Engine system malfunction

1. Difficulty or inability to start

Fault analysis:

Low temperature environmental impact: In winter, oil viscosity increases, battery capacity decreases, and diesel atomization is poor, resulting in insufficient compression end temperature and inability to burn diesel.

Oil circuit failure: Fuel tank is empty, fuel filter is clogged, fuel pipe leaks or joint is loose, resulting in fuel supply interruption.

Mechanical failure: Poor meshing between the starter and flywheel teeth, crankshaft locking, and fuel injection pump plunger jamming, resulting in the inability to transmit power.

Improvement suggestions:

Low temperature start-up optimization: use low viscosity engine oil, preheat the battery, and check whether the diesel grade meets the environmental temperature requirements.

Oil circuit maintenance: Regularly clean the fuel filter, check the sealing of the oil pipe, and eliminate air in the oil circuit.

Mechanical maintenance: Adjust the clearance between the starter and flywheel teeth, check the lubrication status of the crankshaft, and replace the worn fuel injection pump plunger.

2. Abnormal smoke emission from the exhaust pipe

Fault analysis:

White smoke: Water in diesel, loose cylinder head bolts, or damaged cylinder gaskets can cause cooling water to enter the cylinder.

Gray and white smoke: The engine temperature is too low, the fuel supply time is too late, and the diesel is not fully burned.

Black smoke: Poor diesel quality, clogged air filter, premature fuel injection timing, leading to incomplete combustion.

Improvement suggestions:

White smoke treatment: replace diesel, tighten cylinder head bolts, and replace cylinder gaskets.

Gray and white smoke treatment: Preheat the engine to normal temperature and adjust the fuel supply advance angle.

Black smoke treatment: use high-quality diesel, clean the air filter, and adjust the fuel injection timing.

2、 Brake system malfunction

1. Brake failure or deviation

Fault analysis:

Brake failure: excessive clearance between the brake drum and brake shoes, failure of the inlet and outlet valves of the brake master cylinder, and excessive wear of the brake friction pads.

Brake deviation: Poor contact between the brake pads of both wheels and the brake drum, inconsistent brake technology, and uneven tire pressure.

Improvement suggestions:

Brake failure handling: adjust the clearance between the brake drum and brake shoe, inspect the inlet and outlet valves, and replace the friction pads.

Brake deviation treatment: Check whether the cylinder leaks oil or gets stuck, adjust the gap between the brake drum and friction plate, and unify the tire pressure.

2. Brake drag

Fault analysis: The brake pedal has no free travel, the master cylinder return spring is too soft, and the gap between the brake shoe and the brake drum is too small.

Improvement suggestions: Adjust the brake pedal stroke, replace the return spring, and adjust the clearance between the brake drum and friction plate.

3、 Drive system malfunction

1. Clutch slipping or incomplete disengagement

Fault analysis:

Slippery: Friction plates are stained with oil or damaged, and the free stroke of the separation bearing is too large.

Incomplete separation: The combined state of the separation bearing is pressed against the separation lever, and there is air in the oil circuit.

Improvement suggestions:

Slipping treatment: Clean or replace the friction plate, adjust the free stroke of the separation bearing.

Incomplete separation treatment: Adjust the length of the push rod of the cylinder assembly and remove air from the oil circuit.

2. Abnormal noise from the gearbox

Fault analysis: Excessive gear wear, damaged bearings, and debris in the gearbox.

Improvement suggestion: Replace worn gears or bearings, and clean up debris in the gearbox.

4、 Hydraulic system malfunction

1. The inclination of the gantry is not synchronized

Fault analysis: The stroke of two tilting cylinders is inconsistent or the size of the cutoff hole at the joint of the cylinder pipeline is inconsistent.

Improvement suggestion: Adjust the stroke of the two tilt cylinders and replace the joint with the same shut-off hole.

2. Automatic lowering of fork door frame

Fault analysis: Insufficient hydraulic oil in the oil cylinder and poor sealing of the multi way valve.

Improvement suggestion: Repair the multi way valve and add hydraulic oil.

5、 Electrical system malfunction

1. Inability or failure to start

Fault analysis: Battery shortage or damage, circuit disconnection or poor contact, damaged starter motor.

Improvement suggestions: Charge or replace the battery, reconnect or tighten the wiring, and replace the starter motor.

2. The lights do not light up or the horn does not sound

Fault analysis: damaged light bulb, damaged light control switch, poor circuit contact.

Improvement suggestion: Replace the light bulb or switch, reconnect or tighten the circuit.

6、 Other common faults

1. Turn towards Heavy

Fault analysis: The valve core of the diversion valve is stuck or the pressure is insufficient, and the oil supply of the steering oil pump is insufficient.

Improvement suggestion: Adjust the pressure of the diversion valve and inspect the steering oil pump.

2. Engine overheating

Fault analysis: Damaged water pump, loose fan belt, water tank leakage or excessive fouling.

Improvement suggestions: repair or replace the water pump, adjust the tightness of the fan belt, and clean the accumulated dirt in the water tank.

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment