Mitsubishi Canter 4D33 24V Starter Installation Method (OEM Standard Version)

I. Pre-installation Preparation (24V-specific)

1. Tools and Materials

• Special Tools: 12–22mm socket wrench set, torque wrench, Phillips/flathead screwdriver, wire crimping tool, insulating tape/heat shrink tubing, high-pressure air gun

• Auxiliary Materials: OEM grade 8.8 or higher high-strength mounting bolts (M10/M12), flat washers, spring washers, conductive paste, medium-strength threadlocker (e.g., Loctite 243), grounding cable with cross-sectional area ≥25mm² (meets high-current requirements of 24V systems)

• Safety Precautions:

1. Disconnect the negative terminals of both batteries first, then the positive terminals.

2. Wait 5–10 minutes after power-off to discharge residual voltage in the starter solenoid (discharge time for 24V systems is longer than that for 12V systems).

3. Wear gloves and safety goggles.

4. Clean oil, carbon deposits, and rust from the starter mounting seat on the right side of the engine flywheel housing to ensure a flat, debris-free mating surface.

2. Core Compatibility Checks

• Meshing Clearance: Manually push the starter drive gear; the clearance between the gear and the flywheel ring gear must be 2–4mm (excessive clearance causes gear chipping, insufficient clearance leads to jamming).

• Voltage Verification: 24V starters are only for dual-battery series systems. Connection to 12V single-battery systems is strictly prohibited.

• Gear Matching: Ensure the drive gear tooth count and module match those of the 4D33 flywheel ring gear. Verify the starter OEM part number (e.g., M008T80071, M008T80072, etc.).

II. Installation Steps (4D33 24V-specific)

1. Mounting Seat Preparation

1. Blow clean the mounting surface and bolt holes with a high-pressure air gun.

2. Straighten or grind any deformed/rusted areas of the mounting seat to prevent starter housing cracking due to uneven stress.

2. Pre-installation and Centering

1. Hoist the starter to the mounting seat and align the 2 main mounting bolts (the 4D33 uses standard M12 bolts). Temporarily screw in the bolts without fully tightening.

2. Adjust the starter angle to ensure the drive gear axis is completely parallel to the flywheel ring gear axis.

3. Manually rotate the crankshaft (using a wrench on the crankshaft pulley) to verify smooth gear meshing without jamming or uneven wear, and confirm proper drive gear retraction.

3. Bolt Tightening (Critical Torque Values)

1. Pre-tightening: 25–30N·m

2. Final Tightening: 45–55N·m (Mitsubishi Fuso 4D33 OEM standard torque)

• Apply threadlocker to the bolt threads after tightening.

• Both spring washers and flat washers are mandatory (to withstand high-vibration conditions of trucks).

4. Electrical Connections (24V High-current Specifications)

(1) Main Power Connection (B+/+ Terminal)

1. Connect the thick positive cable from the dual-battery series system (cross-sectional area ≥35mm²) to the starter B+/+ main terminal.

2. Install flat washers and spring washers; tighten to a torque of 25–30N·m. Apply a uniform layer of conductive paste to the connector to prevent overheating and ablation.

3. Ensure no cable twisting or exposed connectors. Secure the cable with ties and keep it away from high-temperature/moving components such as the exhaust pipe and steering linkages.

(2) Control Circuit Connection (S/50 Terminal)

1. Connect the thin control wire from the ignition switch/start relay output to the solenoid S/50 auxiliary terminal.

2. Wrap the connector with insulating tape or heat shrink tubing. Secure the wiring firmly to avoid interference with the flywheel housing and drive shaft.

(3) Ground Connection (Critical Step)

1. Confirm reliable grounding between the starter housing and the engine block (poor grounding in 24V systems can cause weak cranking and terminal ablation).

2. If the grounding resistance exceeds 0.5Ω, install a dedicated grounding cable with cross-sectional area ≥25mm². Connect one end to the starter housing ground stud and the other end to the engine block/frame ground point; tighten to a torque of 20–25N·m.

III. Post-installation Commissioning (24V-specific)

1. Power Restoration

• Reconnect the positive terminals of both batteries first, then the negative terminals.

• Inspect the area around the starter for no leftover tools or debris, and confirm no cable pinching or abrasion.

2. No-load Test

• Turn on the ignition switch and crank the starter for ≤5 seconds per cycle (24V starters draw high no-load current; prolonged cranking causes overheating).

• Observe smooth starter operation without abnormal noise or smoke, and verify free extension and retraction of the drive gear.

3. Load Test

• Loose/oxidized cable connectors

• Insufficient dual-battery static voltage (≥24V total, ≥12.4V per battery)

• Poor grounding connection

• Solenoid malfunction

• Start the engine and check for the absence of gear meshing noise. The drive gear must retract within 1 second after engine startup.

• If cranking is weak, troubleshoot the following:

Key Installation Precautions for Mitsubishi Canter 4D33 24V Starter

I. Pre-installation Safety and Compatibility Precautions

Power-off Operation Specifications

Strict Prohibition of Voltage Mismatch

Precise Gear and Clearance Matching

1. Verify the starter’s OEM part number (e.g., M008T80071, M008T80072) to ensure the drive gear’s tooth count and module exactly match those of the 4D33 flywheel ring gear. Mismatched parameters will directly cause gear chipping or jamming.

2. Manually push the drive gear and measure the meshing clearance with the flywheel ring gear—it must be controlled within the range of 2–4mm. Excessive clearance leads to gear impact damage, while insufficient clearance prevents the gear from fully extending or causes it to jam during retraction.

Mounting Seat Preparation Requirements

1. Use a high-pressure air gun to blow away oil, carbon deposits, and rust from the mounting surface.

2. Sand the mating surface until metallic luster is visible.

3. If the mounting seat is deformed or cracked, straighten or replace it prior to installation to avoid uneven bolt stress, which can cause the starter housing to crack.

References：

I. Core OEM Basis (Mitsubishi Fuso Official)

Core Manuals

1. Canter FE7/FE8 Series (4D33 Engine) Workshop Manual - Electrical System (Volume on Starter Installation/Removal/Commissioning)

2. Mitsubishi Fuso 4D33 Engine Service Manual (Chapters covering engine electrical system, fastener torque, and grounding specifications)

3. Fuso Canter Maintenance and Repair Manual (4D33 Model) (Including safety operation, anti-loosening, and wiring protection requirements for 24V electrical systems)

Publisher

Access Channels

1. Authorized Mitsubishi Fuso service centers/dealers (original paper/electronic manuals)

2. Mitsubishi Fuso Tech Info Portal (https://mitsubishitechinfo.com) — official technical information platform (authorized account required)

3. Fuso official service websites for China/Taiwan regions (https://www.fuso.com.cn / https://fuso.tw)

4. Mitsubishi Motors official technical documentation channels

II. General Industry Standards (Supplementary Basis, Globally Applicable)

1. SAE J1802: Automotive Starter Motor Installation and Performance Standards — covering core requirements such as meshing clearance, torque values, electrical connections, and anti-loosening measures

2. ISO 6469: Road vehicles — Electrical equipment — Safety requirements — specifying safety, grounding, and wiring protection standards for 24V high-current systems

3. GB/T 19063-2009: Automotive Starters — Installation Specifications (equivalent to the corresponding ISO standard, implemented domestically in China)

4. Mitsubishi Fuso Corporate Standard: MFTBC-STD-EL-001 (Installation and Anti-loosening Specifications for Commercial Vehicle 24V Electrical Systems, tailored for high-vibration and heavy-duty operating conditions)