12V Alternator Lester 23956 1800A115 A003TG4679 A3TG4679 For Mitsubish Pajero

I. Installation Method

1. Preparation and Safety Measures

• Disconnect the Battery Negative Terminal: This is the most critical step to prevent short circuits caused by accidental contact with tools during installation.

• Prepare Tools: Socket wrenches (usually 10mm, 12mm, 14mm, 17mm, etc.), ratchet wrench, extension bars, 10mm box-end wrench (for removing the bottom bolt), belt tensioning tool (if equipped with an automatic tensioner), or a pry bar (for manual tensioning).

2. Removing the Old Alternator (Reverse the steps for installation)

1. Remove the engine cover (if equipped).

2. Remove the drive belt:

• Automatic Tensioner: Use a wrench to turn the center bolt of the tensioner to release belt tension, then remove the belt.

• Manual Adjustment: Loosen the alternator mounting bolts and the adjustment arm bolt, push the alternator towards the engine, and remove the belt.

3. Disconnect electrical connections:

• Remove the 12mm or 14mm nut from the B+ terminal (alternator output end) and disconnect the power cable (ensure insulation to prevent grounding).

• Unplug the voltage regulator connector (usually a 2-pin or 3-pin plug).

4. Remove mounting bolts:

• There are usually 2-3 mounting bolts (1 at the top, 1-2 at the bottom). The bottom bolt can be difficult to reach and may require a long extension bar or a box-end wrench.

5. Remove the alternator: Take out the old alternator from above or below the engine bay (depending on vehicle space).

3. Installing the New Alternator

1. Install the new alternator: Place the new alternator into the mounting bracket and hand-tighten the mounting bolts initially, but do not fully tighten them yet.

2. Connect electrical wiring:

• Plug in the voltage regulator connector.

• Install the B+ power cable, ensure the washer is correctly positioned, and tighten the nut (this step is recommended before belt tensioning to avoid insufficient working space).

3. Install the drive belt:

• Refer to the belt routing diagram (usually affixed inside the engine bay or on the radiator support) to mount the belt correctly.

4. Adjust belt tension (Critical Step):

• Manual Adjustment Type: Insert a pry bar between the alternator housing and the engine fixed point (place a wooden block to protect the housing), and pry the alternator outward to tension the belt. While maintaining tension, alternately tighten the pivot bolt (mounting bolt) and the adjustment bolt.

• Automatic Tensioner Type: Rotate the tensioner, mount the belt, and release the tensioner to allow it to lock into the belt groove.

5. Final Tightening: After confirming the belt is correctly positioned (seated in the pulley grooves), fully tighten all mounting bolts.

4. Inspection and Testing

• Check if the belt is centered on all pulleys and not twisted.

• Reconnect the battery negative terminal.

• Start the engine, check for any abnormal noise (squeaking) from the alternator belt, and observe if the dashboard charging indicator light turns off.

Mitsubishi Pajero Alternator Installation Precautions

1. Electrical Safety (Crucial)

• Must Disconnect the Battery Negative Terminal: Always disconnect the battery negative terminal before removing or installing any electrical connectors.

• Risk: The alternator output terminal (B+ terminal) is directly connected to the battery positive. If operated while energized, should a wrench touch the engine block (ground), it will instantly create a short circuit with thousands of amps, causing melting wires, battery explosion, or destruction of the Electronic Control Unit (ECU).

• B+ Terminal Nut Torque: The B+ terminal nut must be tightened to the specified torque (usually 8-10 N·m).

• Consequence: If loose, high current passing through a poor connection generates extreme heat, which can cause the terminal to glow red or melt the wire insulation, potentially starting a vehicle fire.

• Clean Corrosion: Check the B+ terminal and plug for oxidation or green/white corrosion powder. If present, clean it thoroughly with sandpaper or a wire brush/rust remover to ensure good conductivity.

2. Belt Tension Adjustment (Core Challenge)

• Manual Adjustment Type (Mechanical):

• Deflection Standard: Press down firmly with your thumb in the middle of the longest span of the belt; it should deflect by 10mm - 15mm (approximately one knuckle depth).

• Do Not Over-Tighten: This is the most common mistake. An over-tightened belt exerts immense pressure on the alternator and water pump bearings, leading to noise or seizure after a few thousand kilometers.

• Use Proper Tools: When using a pry bar to lever the alternator, always place a wooden block between the pry bar and the housing.

• Taboo: Never pry directly against the alternator's aluminum housing or the oil pan; aluminum is very brittle and prone to cracking.

• Automatic Tensioner Type:

• After installation, observe the position of the tensioner pointer. If the pointer is within the green zone, tension is normal. If it is in the red zone or out of range, the belt may be aged/stretched or the tensioner has failed and needs replacement.

3. Mechanical Installation Details

• Bolt Installation Sequence:

1. First, install and hand-tighten all mounting bolts (pivot bolt and adjustment arm bolt).

2. After adjusting the belt tension, cross-tighten the bolts.

3. Finally, lock the adjustment nut.

• Torque Specifications:

• Alternator Mounting Bolt (Pivot Bolt): Usually 35 - 45 N·m (specifics depend on displacement; e.g., 3.0L and 3.8L may differ slightly).

• Adjustment Arm Nut: Usually 20 - 25 N·m.

• Prevent Bottom Bolt from Falling: The bottom mounting bolt of the Pajero alternator is located deep within the engine bay. It is recommended to use a magnetic socket or a magnetic retrieval tool during removal and installation to prevent the bolt from accidentally falling deep into the engine bay or behind the pulley, which would be extremely difficult to retrieve.

4. Belt Routing and Alignment

• Routing Diagram: Before installation, always check the original belt routing sticker on the firewall or radiator support. If the sticker is missing, take a photo before removing the old belt.

• Pulley Groove Alignment: Ensure the belt is fully seated in the bottom of the grooves of the crankshaft pulley, water pump pulley, and alternator pulley.

• Consequence: If the belt rides on the edge of the pulley (not in the groove), the engine will shred the belt edge in seconds, leading to a breakdown.

• Check Idler/Tensioner Pulleys: If your Pajero has high mileage, it is recommended to check the belt tensioner/idler pulley bearings for noise or play. Alternator belt breakage is often caused by a seized tensioner, not the alternator itself.

References：

Primary Technical Sources (Core References)

• Applicable Versions: Manuals corresponding to model years such as the V73/V77 (6G72 3.0L), V93/V97 (6G75 3.8L), and Diesel versions (4M40/4M41). The relevant section is typically found under "Engine Electrical – Alternator Installation."

• Key Basis: Explicitly specifies the B+ terminal torque (8–10 N·m), mounting bolt torque (35–45 N·m), belt tension specifications, installation sequence, and circuit safety operation requirements.

• Access: Mitsubishi authorized dealer service systems, the Mitsubishi Techinfo official website, or compliant electronic manual platforms (e.g., service-workshopmanual.com).

• Content Coverage: Step-by-step decomposition adapted to the vehicle model, torque parameters, electrical connector locations, belt routing diagrams, etc. These align highly with the OEM manuals and cover different model years and displacements.

• Application Scenario: A standardized reference commonly used by service technicians to verify installation procedures and safety key points.

• Function: Cross-references alternator mounting bolt specifications, washer models, and wire harness terminal types to ensure installed components match OEM standards, preventing poor contact or assembly errors.

Supplementary Reference Sources

• Content: Techniques for removing and installing bottom bolts, operational experience with space-constrained models, and actual troubleshooting cases for belt slippage/abnormal noise. Used to optimize practical operational details.

• Key Points: Voltage regulator connector connection specifications, B+ terminal anti-corrosion treatment, and charging system test standards (idle voltage 13.5–14.5V). This strengthens the sections on electrical safety and performance verification.