starter 119740-77020，CST40361AS，4280003310,4280003670 STN3310YJ 11945077010, 11974077020 STN3310ML 4280003670 FOR Hino

I. Preparation and Safety Precautions

1. Safety Confirmation:

• Ensure the vehicle is parked securely, the parking brake is applied, the transmission is in neutral, and the engine is turned off.

2. Disconnect Power:

• Always disconnect the negative (-) battery cable first.

• Heavy-Duty Vehicle Note: Some Hino models are equipped with a Master Switch; ensure it is in the "OFF" position.

3. Tool Preparation:

• Socket set (12mm, 14mm, 17mm, 19mm, 22mm, etc., depending on the specific model such as 300 Series or 500 Series).

• Torque wrench (capable of handling higher torque ranges required for heavy-duty vehicles).

• Belt tensioning tool (for automatic tensioners) or a pry bar (for manual adjustment types).

• Lithium-based grease (for inspecting pulley bearings).

II. Installation Steps (Standard Procedure)

1. Inspection and Pre-lubrication

• Inspection: Confirm that the new alternator pulley rotates smoothly without binding or abnormal noise.

• Lubrication: If the alternator uses manual adjustment, apply a small amount of grease to the adjustment bracket pivot point to prevent rust-related adjustment difficulties.

2. Install the Alternator Assembly

• Position the alternator on the mounting bracket.

• Insert the mounting bolts (typically the pivot bolt and the adjustment arm bolt).

• Key Point: Do not fully tighten at this stage. Only tighten by hand until snug, allowing the alternator to swing freely around the pivot.

3. Install the Drive Belt

• Verify Routing: Strictly follow the diagram on the engine side sticker or the service manual. Hino engines usually have multiple pulleys (Crankshaft, Water Pump, A/C, Fan, Alternator); incorrect routing can cause the fan to reverse or result in insufficient charging.

• Mount Belt: Place the belt over all pulleys.

4. Tension the Belt (Core Step)

• Method A: Automatic Tensioner (Common on newer engines like J08E)

• Use a dedicated tool to rotate the tensioner arm and compress the spring.

• After mounting the belt, slowly release the tool to allow the tensioner to automatically tension the belt.

• Check that the tensioner pointer falls within the scale range (usually the Cold or Hot zone).

• Method B: Manual Adjustment (Common on older models or 300 Series)

• Use a pry bar at the dedicated stress point on the alternator bracket (Never pry against the pulley) to lever the alternator outward and increase belt tension.

• Press the center of the longest belt span; standard deflection is typically 10-15mm (Heavy-duty belts may require being tighter).

5. Tighten Mounting Bolts

• While maintaining belt tension, use a torque wrench to tighten the bolts.

• Reference Torque (Consult the specific engine manual for exact values):

• Pivot Bolt: Typically 60 - 80 N·m.

• Adjustment Lock Bolt: Typically 40 - 55 N·m.

6. Electrical Connections

• Connect the B+ terminal (output) cable. This terminal carries high current, so the nut must be securely tightened.

• Reference Torque: B+ terminal nut is typically 12 - 15 N·m.

• Install the insulating protective cover (Very Important to prevent short circuits caused by oil splatter).

• Connect the voltage regulator plug (if equipped).

7. Restore Power

• Reconnect the negative (-) battery cable.

III. Post-Installation Inspection and Testing

1. Visual Inspection:

• Ensure the belt is not twisted and its edges do not protrude beyond the pulleys.

• Check that all wiring harnesses are routed away from the belt and fan to prevent wear.

2. Functional Testing:

• At Idle: Voltage should be between 13.5V - 14.5V.

• At High Idle (approx. 1500-2000rpm): Voltage should stabilize between 14V - 14.8V.

• Start the engine and observe if the dashboard "Charging Indicator Light" turns off.

• Voltage Test:

• Load Test: Turn on high-current consumers like headlights and A/C. The voltage should not drop below 13V; if it does, it indicates belt slippage or insufficient alternator output.

I. Electrical Safety and Short Circuit Prevention (Heavy-Duty Specific Risks)

• Action: In addition to disconnecting the negative (-) battery cable, always ensure the vehicle's Master Switch is in the "OFF" position.

• Reason: Hino vehicles are typically equipped with high-capacity batteries and thick cables. The arc energy generated by a short circuit is immense; it can not only burn out the alternator diodes but also instantly melt cables or even ignite surrounding oil deposits.

• Action: The B+ terminal nut at the back of the alternator must be tightened to the specified torque (usually 12-15 N·m), and the insulating protective cover must be installed.

• Hino-Specific Risk: A significant amount of oil mist or muddy water can splash inside the engine compartment while the truck is driving. If the B+ terminal is exposed, accumulated sludge can cause a micro-short circuit to ground, resulting in continuous battery drain, or even fraying wires under high vibration, which can trigger a fire.

• Consequence: The internal rectifier bridge of Hino alternators (usually supplied by Denso or Bosch) is extremely sensitive to polarity. If connected in reverse, internal components will burn out instantly, and the damage may spread to the vehicle's ECU (Engine Control Unit).

II. Mechanical Operation and Belt System (Core Lifespan Factors)

• Taboo: When manually adjusting belt tension, absolutely never insert a pry bar into the alternator pulley cooling vents or pry directly against the pulley face.

• Consequence: This will directly shatter the internal rectifier diodes or damage the rotor bearings. Force must only be applied using the dedicated adjustment arm or at specific stress points on the alternator housing.

• Standards:

• New Belt: Deflection should be minimal (Reference: approx. 8-10mm).

• Old Belt: Deflection can be slightly greater (Reference: approx. 10-15mm).

• Risk: Hino engines produce significant vibration. A belt that is too loose will slip and glaze, while a belt that is too tight will directly cause premature wear of the alternator bearings (a primary cause of alternator noise).

References：

I. Core Official Authoritative Sources (Primary Basis)

• Section Location: Engine Electrical System. Commonly found in Section 09 or Section PG (Power Generation). Section numbers may vary slightly by engine model (e.g., J05E, J08E, N04C).

• Core Content: Explicitly mandates power disconnection requirements, B+ terminal insulation specifications, and torque parameters (60–80 N·m for pivot bolts, 40–55 N·m for adjustment bolts, 12–15 N·m for the B+ terminal). It also includes safety warnings regarding belt routing, tension standards, and prohibitions against disconnecting the battery while the engine is running.

• Technical Parameters: The Service Data Sheets (SDS) contain specific values for mounting bolt torque and belt tension ranges for each model/engine.

• Manual Number Examples: J08E Engine Manual No. S5-UJ08E16A; J05E Engine Manual No. S5-YJ05E12D, etc.

• Engine Compartment Belt Routing Sticker: The factory-installed belt routing diagram serves as the direct and authoritative basis for belt installation direction.

• Hino Technical Service Bulletins (TSB): These address common installation issues for specific production batches, providing revised steps and precautions (e.g., insufficient charging caused by tensioner spring fatigue).

II. Component Supplier Technical Specifications (Core Component Basis)

• Since many Hino alternators are supplied by Denso, this guide specifies core requirements such as electrical connection safety, B+ terminal insulation protection, and prohibition of reversed polarity, which align with the Hino official manual.

• For Hino models equipped with Bosch alternators, this specification emphasizes key points such as torque control, belt tension adjustment, and mechanical operation taboos.

III. Industry General Standards and Supplementary References (Compliance and Practical Basis)

• These address the specific characteristics of commercial vehicles (high vibration, heavy loads), regulating safety requirements such as power disconnection procedures, torque control, and foreign object prevention. They are applicable to Hino truck/bus usage scenarios.

• These contain practical precautions compiled from factory manuals, including details on electrical safety and mechanical operation taboos. They are suitable for troubleshooting common scenarios in Hino vehicles.