The ARB CKMA12 is a high-output on-board air compressor designed for use with air-activated systems such as locking differentials or tire inflation kits. It is a compact, highly configurable unit suitable for a range of vehicle installations. This article provides a detailed, step-by-step guide for installing the CKMA12, based on the official manufacturer documentation and real-world installation examples. The guide is tailored for U.S.-based users and emphasizes best practices, safety, and compatibility with American vehicle models.
Introduction
The ARB CKMA12 is a 12V model certified to meet EN 55014.1 (AS/NZS CISPR 14.1) standards and complies with Australian and European directives. It includes all necessary components for installation—such as a wiring harness, mounting hardware, pressure switch, and air filter—as well as detailed instructions for setup. While the compressor is designed for self-installation, ARB strongly recommends that it be installed by a trained professional due to the complexity of routing and securing the system.
The installation process involves identifying a suitable mounting location, configuring the compressor to fit, drilling and securing the unit, and connecting the air and electrical systems. This article outlines each of these steps based on the official installation guide and a real-world example of its use in a Ram 3500.
Pre-Installation Preparation
Before beginning the installation, it is essential to gather the necessary tools and materials. The manufacturer recommends the following:
- A comprehensive toolkit for drilling, fastening, and electrical work
- A multimeter for testing electrical connections
- Cable ties and protective materials (such as split loom) for securing wiring
- Teflon tape for sealing air fittings
- Paint and primer for corrosion protection (as shown in a user example)
- An optional pump-up kit for tire inflation
In addition to the tools, the user should read the entire installation guide before proceeding. ARB emphasizes that planning and preparation are critical to ensuring a safe and reliable installation.
Identifying the Best Mounting Position
The first step in the installation process is to identify an appropriate mounting location for the compressor. According to the manufacturer's instructions, the ideal location should:
- Allow for easy access to the compressor for maintenance or the attachment of an optional pump-up kit.
- Be secure and stable to minimize vibration and noise.
- Not interfere with existing vehicle components or wiring.
- Provide adequate space for the air line connections and electrical wiring.
In a real-world example, a user installed the CKMA12 on a Ram 3500 by mounting it behind the driver-side headlight. This location was chosen to avoid interference with other components and to provide sufficient space for routing the air lines and electrical harness.
Configuring the Compressor for the Best Fit
The CKMA12 is designed to be highly configurable, allowing it to adapt to a wide range of mounting scenarios. Once the ideal mounting location has been identified, the shape of the unit can be adjusted to best suit the space and ensure optimal access to the ports. The manufacturer notes that the unit’s mounting bracket holes are slotted in a circular pattern, allowing the backing plate and bolts to be partially rotated relative to the compressor body.
This flexibility enables the installer to position the compressor in a way that is both secure and visually unobtrusive. In the example installation, the user configured the compressor to fit behind the headlight and adjusted the mounting angle to ensure proper alignment with the air system.
Drilling and Mounting the Compressor
To mount the compressor, the user should use the metal base plate included with the unit as a template to mark the drilling locations. The base plate is then bolted to the chosen mounting surface using the appropriate fasteners. The manufacturer specifies a 10mm socket for tightening the bolts to approximately 9 Nm [6.6 ft-lb] of torque.
In the example installation, the user removed the windshield washer reservoir and a large air hose to create enough space for the compressor. The base plate was then mounted using 2.5" hex head bolts, self-locking nuts, and washers to reduce vibration and noise. The base plate was primed and painted black to prevent corrosion and improve aesthetics.
Once the base plate is in place, the compressor body is attached to the mounting bracket using the bolts provided. The user also added plastic washers between the bracket and the compressor to dampen vibrations and reduce noise during operation.
Installing the Solenoid and Pressure Switch
The solenoid is part of the air system and is used to control the flow of compressed air to the locking differential or other components. The manufacturer notes that this step is specific to the 12V solenoid included with the ARB Air Locker differential. If the compressor is being used for a different application, the solenoid may be skipped, and the ports should be plugged or terminated accordingly.
The pressure switch is another critical component that monitors the system pressure and controls the compressor’s operation. It is installed according to the manufacturer’s instructions and connected to the air system using appropriate fittings and Teflon tape for a secure seal.
Assembling and Installing the Air Filter
The air filter is an essential part of the system, as it prevents dirt, dust, and moisture from entering the compressor and damaging internal components. The filter should be installed in a location that is not exposed to these contaminants. In the example installation, the user attached the air filter using an air filter extension tube to position it away from potential sources of dirt.
The manufacturer recommends using a generous amount of orange Teflon tape when connecting the air filter to ensure a leak-free seal. The user also added a ¼ male to ¼ compression adapter to connect the filter to the air line.
Connecting the Air System
Once the compressor is mounted and the air filter is installed, the next step is to run and secure the air line to the axle or other components. The air line should be routed in a way that minimizes the risk of snagging, rubbing, or damage. The manufacturer recommends using cable ties to secure the air line and electrical harness to the vehicle frame or other structural components.
In the example installation, the user used a 1/4" 150 PSI air tube to connect the compressor to the air locker bulkhead fitting. The air line was secured with nylon cable ties and protected with electrical tape and split loom.
Electrical Connections
The CKMA12 comes with a full wiring harness that connects to the vehicle’s electrical system. The user should follow the manufacturer’s instructions for connecting the harness to the battery and relay system. The manufacturer recommends using a 12V - 40A relay of the same type for compatibility and reliability.
To test the electrical connections, the user should use a multimeter to check for motor voltage between the battery’s negative terminal and the RED-WHT wire connected to the relay block. If voltage is detected, the system is functioning correctly. If not, a faulty relay may be the cause, and it should be replaced.
Testing and Troubleshooting
After the installation is complete, the manufacturer recommends performing a post-installation check to ensure all components are properly connected and functioning. This includes:
- Leak testing the air system to ensure there are no air leaks.
- Verifying that the air filter is positioned away from moisture, dust, or dirt.
- Ensuring all air lines and wiring are securely fastened and protected from snagging.
If the system does not operate as expected, the user should refer to the troubleshooting section of the manual. Common issues include loose connections, faulty relays, or incorrect wiring. The user example noted the use of Teflon tape and proper sealing techniques to prevent air leaks.
Project Difficulty and Materials
The manufacturer and user example both note that the CKMA12 is a moderately difficult installation due to the need for careful planning, drilling, and routing. The user rated the project as "medium" in difficulty, indicating that it requires a reasonable amount of mechanical skill and attention to detail.
The materials used in the example installation included:
- ARB CKMA12 High-Output Air Compressor
- 2.5" Hex Head Bolts (4)
- Self Locking Nuts (4)
- Flat Washers (4)
- Plastic Washers (4)
- 1/4" 150 PSI Air Tube
- ⅛ Male to ¼ Compression Adaptor
- Orange Teflon Tape
- Rust Oleum Primer
- Rust Oleum Flat Black Paint
- Nylon Cable Ties
- Electrical Tape
- Split Loom
These materials are all recommended for a durable and reliable installation. The user also noted the importance of using corrosion-resistant materials, such as primer and paint, to protect the mounting components from rust and wear.
Conclusion
The ARB CKMA12 is a versatile and high-output on-board air compressor suitable for a wide range of vehicle applications. Its compact design and high configurability make it ideal for installations in tight spaces, such as under the hood of a Ram 3500. However, due to the complexity of routing and securing the system, it is recommended that the installation be performed by a trained professional.
The installation process involves several key steps: identifying the best mounting location, configuring the compressor for the best fit, drilling and securing the unit, installing the solenoid and pressure switch, assembling the air filter, and connecting the air and electrical systems. The user example provided a detailed breakdown of how these steps were applied in a real-world installation.
By following the manufacturer’s instructions and using the recommended tools and materials, users can ensure a safe, reliable, and long-lasting installation. The post-installation check and troubleshooting steps are also essential for verifying the system’s performance and identifying any potential issues.