24V 60A 9PK alternator for Hino 27060-EW010/0201-172-2312，27060EW010/02011722312

Installation Guide for Hino 24V Alternators

I. Preparation and Safety

• Before performing any work, always disconnect the negative (-) battery terminal first.

• Reason: The B+ terminal of the Hino alternator is usually connected directly to the positive battery terminal. In a 24V system, the current is extremely high; a short circuit caused by a tool can produce lethal sparks or damage electronic components.

• Socket Wrenches: Usually 12mm, 14mm, 17mm, and 19mm (specific sizes depend on the model).

• Ratchet Wrench and Extension Bars.

• Torque Wrench (for tightening the belt tensioner and mounting bolts).

• Parts: New alternator, new belt (recommended for replacement), and new washers.

II. Remove the Old Alternator (Reverse Reference)

• First, remove the plug (usually a 4-pin or 2-pin plug for the voltage regulator).

• Remove the nut (usually 12mm or 14mm) from the thick output cable at the (B+) terminal and disconnect the cable.

• Tip: If space is limited, you may need to remove the air filter housing or intake pipe first.

• Locate the automatic tensioner (usually featuring a 1/2-inch square hole or hex head).

• Use a special tool or wrench to rotate the tensioner, releasing belt tension, and slide the belt off the alternator pulley.

• Hino alternators are typically secured by 2 main mounting bolts and 1 adjustment/pivot bolt.

• Unscrew the bolts sequentially and remove the old alternator.

III. Install the New Alternator (Core Steps)

• Place the new alternator into the mounting bracket position.

• Insert the main mounting bolts and the pivot bolt, threading them in by hand first to ensure alignment and prevent cross-threading.

• Do not fully tighten yet; leave the alternator slightly loose so it can pivot.

• Rotate the automatic tensioner and loop the new belt into the grooves of the alternator pulley.

• Slowly release the tensioner to allow it to apply pressure to the belt.

• Check: Ensure the belt has not slipped off the edge of the pulley and that it is seated in all grooves.

• Fine-tune the position of the alternator up and down to ensure the belt is in the same plane as the crankshaft pulley.

• Torque: Tighten the mounting bolts according to the service manual specifications (usually 40-50 N·m for main bolts, 30-40 N·m for tensioner bolts).

• Connect Thick Wire First: Reattach the output cable to the B+ terminal and tighten the nut (recommended to apply a small amount of thread lock to prevent loosening).

• Connect Plug Second: Insert the voltage regulator plug and ensure the clip locks into place.

IV. Commissioning and Testing

• Reconnect the negative (-) battery terminal.

• Start the engine and let it idle.

• Use a multimeter to measure the voltage across the battery terminals.

• Standard Value: The normal charging voltage for a 24V system should be between 27V - 28.5V. If it is below 26V, the belt may be slipping, or the alternator may be faulty.

• Rev the engine slightly and listen for any abnormal noises from the alternator bearings (such as grinding or squealing).

Precautions for Installing Hino 24V Alternators

I. Electrical Safety (Critical)

• Operation: When installing the battery, must confirm the positive and negative terminals are correct.

• Consequence: The rectifier diodes inside the Hino alternator have no reverse polarity protection. If the positive and negative terminals are reversed, the diodes will short-circuit and explode instantly, directly burning out the alternator. It cannot be repaired and must be scrapped.

• Operation: Before removing or installing any wiring, must first disconnect the negative (-) battery terminal.

• Reason: The output terminal (B+) of the Hino alternator is directly connected to the positive battery terminal. In a 24V system, if a wrench or metal object touches both the B+ terminal and the engine block (ground) simultaneously, it will generate a short-circuit current of several thousand amps, causing an arc explosion that could result in burns or vehicle fire.

• Warning: Do not test if the alternator is generating electricity by "scraping" the wire against the engine block to see if there are sparks (a method sometimes used for household circuits).

• Consequence: This will cause breakdown of the internal electronic components of the voltage regulator or damage the vehicle's ECU/ECM.

II. Mechanical Installation (Determines Lifespan)

• Detail: Hino engine alternator brackets are usually made of cast aluminum or cast iron, with deep threaded holes.

• Operation: Mounting bolts must first be screwed in by hand a few turns to confirm the threads are aligned before tightening with a tool.

• Consequence: If the threads are misaligned and you use an air impact wrench directly, it will cause thread stripping. Repairing the threaded holes on the engine block is very troublesome and expensive.

• Problem: If the belt is too loose, it will slip, leading to insufficient power generation and high-temperature melting of the belt; if the belt is too tight, it will break the alternator bearing.

• Standard:

• Automatic Tensioner: Ensure the tensioner can swing freely and the belt is embedded at the bottom of the pulley groove (not floating).

• Manual Adjustment: Press the middle of the belt with your thumb; the deflection should be around 10mm - 15mm (depending on belt length).

• Hidden Danger: The alternator output wire (B+ wire) is usually thick and stiff.

• Check: After installation, must check if the wiring harness will touch the fan blades, belt, or exhaust manifold due to engine vibration.

• Countermeasure: Use high-temperature resistant zip ties to secure the wiring harness to the bracket to prevent wear and leakage.

References：

Source Attribution and Verification References

I. Core Authoritative Sources (Directly Verifiable)

II. Content Traceability Explanation

• Electrical Safety Rules (Reverse connection prohibition, disconnect negative first, strictly prohibited spark testing): Derived from the mandatory power disconnection process and terminal specifications in the Hino OEM manual, while also complying with the electrical connection safety guidelines in QC/T 518.

• Mechanical Installation Points (Hand-threading bolts to prevent stripping, belt tension 10–15mm deflection, coaxiality check): Based on installation specifications tailored to the material properties of Hino engine brackets (cast aluminum/cast iron), referencing OEM torque parameters (main bolts 40–50 N·m, tensioner 30–40 N·m).

• Component Inspection Standards (Overrunning pulley test, flywheel ring gear check, insulation securing): Integrated from Hino OEM assembly requirements and ISKRA component technical specifications to ensure no interference or short-circuit risks after installation.

• Trial Operation Judgment (Charge indicator light status, voltage 27–28.5V, abnormal noise identification): Based on QC/T 518 charging performance indicators and Hino OEM fault diagnosis procedures to ensure the normal operation of the power generation system.