The ARB Air Locker is a popular off-road modification for vehicles equipped with 31-spline differentials, such as the Nissan H233B. This article provides a detailed overview of the installation process, based on information from manufacturer documentation, user experiences, and installation guides. The installation procedure is specific to the ARB RD136 model, which is designed for air-operated locking differentials. The guide covers tools, components, step-by-step procedures, and troubleshooting tips based on verified sources.
Introduction
The ARB Air Locker is an air-activated differential locking system designed to improve traction in off-road conditions. It is commonly used in vehicles with rear or front differentials that support 31-spline gears, such as the Nissan H233B. The system consists of a locking carrier, air solenoid, air fitting, and manifold, along with the air compressor and wiring harness. Proper installation requires attention to detail, particularly regarding sealing of air connections and electrical wiring to avoid leaks and ensure reliable operation.
This article outlines the installation process, tools required, and key considerations for successful implementation of the ARB Air Locker system. It draws from official installation guides, user reports, and manufacturer recommendations to provide a comprehensive and accurate resource for DIY mechanics and automotive enthusiasts.
Key Components of the ARB Air Locker System
The ARB Air Locker system includes several key components that must be installed and configured correctly to ensure proper function. These components are:
Locking Carrier: The central mechanical component of the system, responsible for engaging and disengaging the differential lock.
Air Solenoid: A valve that controls the flow of compressed air to the locking carrier. It is typically mounted near the differential housing.
Air Fitting and Bulkhead: Used to connect the air line to the differential housing. The bulkhead fitting includes a spring to prevent the air line from being crimped or damaged during vehicle articulation.
Air Compressor: Provides the necessary air pressure to operate the locking mechanism. It must be mounted in a suitable location and connected to the vehicle's electrical system.
Manifold: A central hub for connecting air lines to the compressor, solenoid, and tire inflation system. It is required for both Air Lockers and tire inflation applications.
Wiring Harness and Switch: The electrical system includes a switch for activating the locker, a relay, and a pressure switch that controls compressor activation based on air pressure levels.
Thread Sealant and Teflon Tape: Used to ensure air and electrical connections are leak-free and secure.
Mounting Brackets and Hardware: Provided by ARB for securing the compressor and manifold to the vehicle.
Tools and Accessories Required for Installation
Proper installation of the ARB Air Locker system requires a set of tools and accessories, which are outlined in the manufacturer’s installation guide and user reports. These include:
Basic Mechanics Tool Set: Includes wrenches, sockets, screwdrivers, and pliers for disassembling and reassembling components.
Wire Cutters, Strippers, and Crimpers: For preparing and connecting electrical wiring.
Multimeter: Used to test electrical connections and verify proper operation of the wiring harness.
Heat Gun and Soldering Iron: For sealing electrical connections with heat shrink or solder.
Electrical Tape or Heat Shrink: To insulate and protect wire connections.
Cable Ties: For organizing and securing wires and air lines.
Thread Sealant and Teflon Tape: Essential for sealing air and threaded connections to prevent leaks.
Battery Disconnect Tool: To safely disconnect the vehicle’s battery before starting installation.
Mounting Brackets and Hardware: Provided by ARB for securing the air compressor and manifold.
Vehicle-Specific Installation Templates: Used to mark and drill mounting holes for the air compressor.
Installation Steps for the ARB Air Locker System
The installation process for the ARB Air Locker system is outlined in detail in the official installation guide and user experiences. Below is a step-by-step summary of the installation process for the ARB RD136 model on a Nissan H233B 31-spline differential.
1. Disconnect the Vehicle Battery
Before beginning the installation, it is important to disconnect the vehicle battery to prevent electrical shorts or damage to the system. This step is critical for safety and to avoid accidental activation of the electrical components during installation.
2. Select a Mounting Location for the Air Compressor
The air compressor should be mounted in a suitable location, typically near the battery or in a secure area that is accessible for maintenance. ARB compressors come with built-in mounting brackets, but vehicle-specific brackets can also be used for easier installation.
If using the built-in bracket, follow the manufacturer’s instructions to mark and drill mounting holes at the desired location. Secure the compressor using the provided hardware.
If using a vehicle-specific bracket, attach the compressor to the bracket first and then mount the bracket to the vehicle according to the instructions.
3. Install the Air Locker Components
The next step involves installing the air locker components on the differential. This includes:
Mounting the Air Solenoid: The solenoid is typically mounted near the differential housing. Ensure it is securely fastened and connected to the air line.
Connecting the Air Fitting and Bulkhead: The air fitting connects to the solenoid and the bulkhead fitting on the differential housing. Apply Teflon tape to the threads to ensure a leak-free connection. The bulkhead fitting includes a spring that helps prevent the air line from being crimped during articulation.
Routing the Air Line: Route the air line from the solenoid to the differential housing, ensuring it is not kinked or bent excessively. Use 90-degree fittings if necessary to maintain smooth airflow.
4. Install the Manifold
The manifold is a central component for connecting the air compressor, solenoid, and tire inflation system. Follow these steps:
Apply thread sealant to the ¼” fittings. Use a 14mm socket to thread one into the compressor and the other into the manifold.
Apply thread sealant to the hose coupling threads and thread it into the large port on the manifold.
Choose a suitable mounting location for the manifold, no more than 9 inches from the compressor. Some ARB or aftermarket brackets include an integrated manifold mount.
Connect the stainless-steel braided air hose to the compressor and manifold using a 14mm wrench.
5. Connect the Electrical System
The electrical system includes the switch, relay, wiring harness, and pressure switch. The installation steps are as follows:
Mount the Switch and Relay: Install the switch in a convenient location and connect it to the relay. The relay controls power to the air compressor and ensures it only operates when needed.
Connect the Pressure Switch: The pressure switch is essential for monitoring air pressure levels and triggering the compressor to recharge when necessary. It must be connected in line with the air system.
Attach the Harness to the Battery and Ignition Source: The wiring harness connects to the vehicle battery and a keyed ignition source. This ensures the compressor only activates when the vehicle is on.
Connect the ARB Locker Switch: If using a front and rear locker system, the wiring harness includes provisions for activating both lockers. The front locker cannot be engaged unless the rear locker is active, unless this feature is disabled.
6. Test the System
Once all components are installed and connected, it is important to test the system for leaks and proper function. This includes:
Checking for Air Leaks: Use soapy water or a leak detection spray to inspect all air connections. Reapply Teflon tape or thread sealant if any leaks are detected.
Testing the Electrical Connections: Use a multimeter to verify that all wiring connections are secure and functioning correctly.
Testing the Locker Operation: Activate the locker switch and observe whether the differential engages and disengages as expected. The pressure switch should also trigger the compressor to recharge the system when necessary.
If the system cycles on and off frequently, it may indicate a leak in the air system. Recheck all connections and reapply Teflon tape or thread sealant as needed.
Troubleshooting Common Issues
User reports and installation guides highlight several common issues that may occur during or after installation of the ARB Air Locker system. These include:
1. Air Leaks
Air leaks are a common issue, particularly if Teflon tape or thread sealant is not applied correctly. A leak can cause the compressor to cycle on and off frequently as it tries to maintain pressure. To resolve this issue:
- Recheck all air connections and reapply Teflon tape or thread sealant.
- Ensure the bulkhead fitting is securely mounted and not damaged.
- Inspect the air line for kinks or damage and replace if necessary.
2. Electrical Connection Issues
Improper electrical connections can prevent the compressor from operating correctly or cause the locker to fail to engage. Common electrical issues include:
- Loose or Damaged Wires: Ensure all wiring connections are secure and not damaged.
- Incorrect Wiring Harness Configuration: Follow the manufacturer’s instructions carefully to ensure the wiring harness is connected correctly.
- Faulty Pressure Switch: If the pressure switch is not functioning correctly, the compressor may not activate or may fail to recharge the system. Test the pressure switch with a multimeter and replace if necessary.
3. Compressor Failure
The air compressor may fail to operate due to a variety of reasons, including:
- Battery or Electrical Issues: Ensure the vehicle battery is fully charged and the wiring harness is connected correctly.
- Compressor Mounting Issues: If the compressor is not mounted securely, it may vibrate excessively or overheat.
- Air Line Restrictions: Kinks or obstructions in the air line can prevent the compressor from delivering sufficient pressure to the locker system. Inspect the air line and replace if necessary.
Best Practices for ARB Air Locker Installation
To ensure a successful and reliable installation of the ARB Air Locker system, consider the following best practices:
Follow the Manufacturer’s Instructions: The ARB installation guide provides detailed step-by-step instructions and warnings. These should be followed carefully to avoid damage to the components or the vehicle.
Use High-Quality Thread Sealant and Teflon Tape: These materials are essential for preventing air and electrical leaks. Use high-quality products to ensure long-term reliability.
Mount the Compressor in a Secure Location: Choose a location that is accessible for maintenance and not exposed to excessive heat or vibration.
Route Air Lines Carefully: Avoid sharp bends or kinks in the air lines. Use 90-degree fittings to maintain smooth airflow and prevent damage.
Test the System Before Driving: After installation, test the system for leaks and proper function. This ensures the locker will operate correctly when needed.
Regular Maintenance: Periodically inspect the air lines, solenoid, and electrical connections for wear or damage. Replace any damaged components as needed.
Upgrade Gearing for Off-Road Use: As noted in one user report, upgrading to higher gear ratios (e.g., 4.56) can improve performance in off-road conditions by providing better torque and traction.
User Experiences and Tips
Several user reports highlight the benefits and challenges of installing the ARB Air Locker system. One user noted that the ARB installation instructions are among the most detailed and helpful in the aftermarket. However, they also emphasized the importance of using Teflon tape for air connections to prevent leaks. Without proper sealing, the system may fail to maintain pressure, leading to frequent compressor cycling and potential system failure.
Another user shared their experience of modifying the vehicle's axle housing as part of the installation. This included removing the stock housing, cleaning the differential area, and installing new bearings and gears. They also highlighted the importance of cleaning the system thoroughly to avoid contamination and damage to new components.
One user also reported that the ARB system significantly improved their off-road performance, allowing them to navigate sharp turns and inclines without worrying about losing traction. They also appreciated the ability to lock the front axle on command, which provided greater control and confidence in challenging terrain.
Conclusion
The ARB Air Locker system is a valuable addition for off-road vehicles equipped with 31-spline differentials, such as the Nissan H233B. The installation process involves several key steps, including mounting the air compressor, installing the locking carrier, connecting the air solenoid and manifold, and configuring the electrical system. Proper installation requires attention to detail, particularly regarding sealing air connections and verifying electrical connections.
User reports and manufacturer documentation emphasize the importance of following installation instructions carefully and using high-quality materials such as Teflon tape and thread sealant. Regular maintenance and testing are also essential to ensure the system operates reliably in off-road conditions.
For DIY enthusiasts and automotive technicians, the ARB Air Locker system provides an effective way to improve traction and control in challenging terrain. By following best practices and troubleshooting common issues, users can ensure a successful and long-lasting installation.