General Installation Guide for Weichai 24V Alternator

Pre-installation Preparation and Safety Specifications

Vehicle Preparation

1. Turn off the engine, engage the handbrake, and shift the gearbox to P (Park)/N (Neutral).

2. Perform all operations on a cooled engine and keep away from high-temperature/rotating components.

3. Disconnect the main power switch or the negative terminals of dual batteries, wrap the connectors with insulating material, and strictly prohibit live operation on alternator terminals throughout the process.

Tools and Consumables

• Tools: Socket/wrench (sizes: 10/13/14/17/19/22 mm), torque wrench, special belt tensioner tool, brush/cleaning agent.

• Consumables: Copper paste/petroleum jelly, insulating tape, cable ties, lock washers, new belt (if necessary).

Spare Part and Space Confirmation

1. Verify that the alternator model matches the vehicle's model and production year; check for intact appearance and ensure bearings and slip rings rotate smoothly without jamming.

2. Confirm terminal markings (B+/BAT for main power supply, S/IGN for control wire, housing for grounding).

3. Remove obstructive components such as the air filter box and protective covers; take photos to record the installation position of the old alternator and wiring harness routing for easy reassembly.

Step-by-Step Installation Process (Reverse of Disassembly Sequence)

Cleaning & Positioning

Fastening Mounting Bolts

1. First, screw in all fixing bolts by hand.

2. Then use a torque wrench to tighten them diagonally and in stages.

• Reference Torque: 45–60 N·m for mounting bolts, 12–18 N·m for terminal nuts (refer to the official manual for exact values).

• Avoid over-tightening to prevent housing deformation, and avoid under-tightening to prevent resonance and abnormal noise.

Electrical Connection (Core Sequence: Control Circuit First, Power Circuit Second; Thin Wires First, Thick Wires Second)

1. Control Wire (S/IGN): Fully insert the plug or tighten the small nut to ensure a secure connection without loosening or poor contact, which could otherwise cause voltage regulation abnormalities.

2. Main Power Wire (B+/BAT): Connect the thick positive battery cable, tighten it with a lock washer. Apply copper paste or petroleum jelly to the terminal surface to prevent oxidation and ablation.

3. Grounding: The alternator is naturally grounded to the engine block via mounting bolts—ensure the contact surface is free of paint and rust. For models equipped with an independent grounding wire, fasten the wire securely in addition to avoid voltage instability, overheating and regulator burnout.

Belt Installation and Tension Adjustment

1. Route the belt strictly according to the diagram in the engine compartment; never misroute or reverse the belt. For alternators with a one-way pulley, confirm the correct rotation direction.

2. Use a belt tensioner tool to release tension, fit the belt onto the alternator pulley, then release the tool. Press the middle section of the belt—the deflection should be controlled within 10–15 mm (refer to the official manual for exact values).

• Excessive tension will accelerate bearing wear; insufficient tension will cause belt slippage and abnormal noise.

Power Restoration, Testing and Reassembly

1. Check that the wiring harness has no interference or insulation damage, secure it with cable ties, then reconnect the negative battery terminals or close the main power switch.

2. Idle Test: Start the engine—the alternator should run smoothly without abnormal noise, and the belt should show no signs of slippage. The dashboard charging indicator light should turn off, and the voltage should stabilize at 27.5–28.5 V.

3. Load Test: Turn on high-power electrical loads such as headlights and air conditioning—the voltage should remain stable at 27.0–28.5 V without significant drop.

4. Refit all removed components and clean up the work area and tools.

Key Precautions for Installation of Weichai 24V Internally Regulated Alternator

Power-off Operation Must Be Implemented Throughout the Entire Process

1. Prior to installation, disconnect the vehicle's main power switch or the negative terminals of dual batteries, and wrap the connectors with insulating tape to prevent accidental power-on.

2. Live operation on alternator terminals is strictly prohibited throughout the process to avoid arc burns, coil burnout or voltage regulator damage.

3. Before restoring power supply, recheck that all wiring connections are free of loosening and short-circuit risks.

Cleanliness of Mounting Surface and Control of Positioning Accuracy

1. Thoroughly remove oil stains, rust and impurities from the joint surface between the engine mounting bracket and the alternator housing. Residual foreign objects will lead to excessive mounting clearance, resulting in abnormal operation noise, bolt loosening and even shortened bearing service life.

2. Align the mounting holes accurately during positioning. Never strike the alternator housing forcibly; otherwise, the internal rotor, stator coils and bearings will be damaged, rendering the alternator completely unusable.

Bolt Fastening Must Strictly Comply with Torque Standards

1. Both the mounting bolts and terminal nuts must be tightened with a torque wrench. Reference torque: 45–60 N·m for mounting bolts, 12–18 N·m for terminal nuts (refer to the official Weichai service manual for the specific vehicle model for exact values).

2. Adopt the diagonal and staged tightening method to ensure uniform force distribution. Over-tightening will cause housing deformation and bearing jamming; under-tightening will induce resonance and abnormal noise, and in extreme cases, bolt detachment may damage surrounding engine compartment components.

3. 
   

4. References：
   

5. Key Precautions for Installation of Weichai 24V Internally Regulated Alternator

6. These precautions are formulated in accordance with OEM maintenance specifications, with the core objective of avoiding common faults such as short circuits, belt failures and wiring errors, and ensuring the stable operation of the alternator.

7. Power-off Operation Must Be Implemented Throughout the Entire Process

8. Prior to installation, disconnect the vehicle's main power switch or the negative terminals of dual batteries, and wrap the connectors with insulating tape to prevent accidental power-on.

9. Live operation on alternator terminals is strictly prohibited throughout the process to avoid arc burns, coil burnout or voltage regulator damage.

10. Before restoring power supply, recheck that all wiring connections are free of loosening and short-circuit risks.

11. Cleanliness of Mounting Surface and Control of Positioning Accuracy

12. Thoroughly remove oil stains, rust and impurities from the joint surface between the engine mounting bracket and the alternator housing. Residual foreign objects will lead to excessive mounting clearance, resulting in abnormal operation noise, bolt loosening and even shortened bearing service life.

13. Align the mounting holes accurately during positioning. Never strike the alternator housing forcibly; otherwise, the internal rotor, stator coils and bearings will be damaged, rendering the alternator completely unusable.

14. Bolt Fastening Must Strictly Comply with Torque Standards

15. Both the mounting bolts and terminal nuts must be tightened with a torque wrench. Reference torque: 45–60 N·m for mounting bolts, 12–18 N·m for terminal nuts (refer to the official Weichai service manual for the specific vehicle model for exact values).

16. Adopt the diagonal and staged tightening method to ensure uniform force distribution. Over-tightening will cause housing deformation and bearing jamming; under-tightening will induce resonance and abnormal noise, and in extreme cases, bolt detachment may damage surrounding engine compartment components.

17. Electrical Connection Must Follow the Irreversible Sequence

18. Wiring sequence: Connect the control circuit (S/IGN terminal, thin wire) first, then the main power circuit (B+/BAT terminal, thick wire). Reverse the sequence during disassembly to prevent high-current short circuits that could burn out fuses or the alternator.

19. A lock washer must be installed at the main power wire connector. After tightening, apply copper paste or petroleum jelly to the terminal surface to prevent oxidation and ablation.

20. Fully insert the control circuit plug or tighten the small nut to avoid loosening and poor contact, which would otherwise cause voltage regulation abnormalities, no power generation or persistent illumination of the charging indicator light.

21. Guarantee grounding reliability: The alternator is naturally grounded to the engine block through mounting bolts—ensure the contact surface is free of paint and rust. For models equipped with an independent grounding wire, fasten the grounding wire connector securely in addition. Poor grounding will lead to unstable generating voltage, alternator overheating and even regulator burnout.

22.