Converting a 4700 to a Hydrovac Truck: A Detailed Guide

[MikePhua]

Introduction
Converting a standard truck, like the International 4700, into a specialized hydrovac truck is a complex but highly rewarding process. Hydrovac trucks, which use high-pressure water and a vacuum system to excavate soil, are essential for tasks like potholing, utility installation, and trenching. This article outlines the steps and considerations involved in converting a 4700 into a functional hydrovac truck, drawing insights from the forum discussion on this conversion.
Why Convert to a Hydrovac Truck?
The primary purpose of converting a truck to a hydrovac unit is to increase the versatility of the vehicle, allowing it to perform tasks that require high-pressure water and suction capabilities. Hydrovac trucks are often used in construction, utility repairs, and environmental cleaning, making them highly valuable for those in the excavation or maintenance industries.
For someone who already owns a 4700 truck, converting it can be a cost-effective way to enter the hydrovac business without purchasing an entirely new vehicle.
Understanding the Hydrovac System
Before starting the conversion process, it’s essential to understand the components that make up a hydrovac system:

1. Vacuum System: This part of the system uses a powerful vacuum pump to suck the soil, water, and debris into a storage tank.
   
2. Water System: The high-pressure water system is responsible for breaking up the soil. It usually involves a water tank, pump, and hose reel. The water pressure helps to loosen compacted soil, making it easier for the vacuum to remove.
   
3. Debris Storage Tank: A large tank to collect the excavated material, usually mounted on the truck. It should be sealed and capable of handling the pressure created by the vacuum system.
   
4. Hydraulic System: Often used for controlling the boom, which is used to position the hose for excavation. A hydraulic system may be necessary to operate the boom and vacuum hose.
   
5. Control Panel: This is where the operator manages all systems, including water pressure, vacuum strength, and boom positioning.
   

Steps for Converting the 4700 to a Hydrovac Truck

1. Engine and Power Considerations
   • The International 4700 is equipped with a diesel engine, which should be powerful enough to handle the additional load created by the hydrovac system. However, you may need to upgrade the engine or cooling system to ensure it can handle the stress from the hydrovac equipment.
     
   • Consideration for additional auxiliary power to run the vacuum and water systems is essential. This may involve installing a PTO (Power Take-Off) or a separate engine to power these systems.
     
2. Installing the Vacuum and Water Systems
   • A hydrovac unit typically involves significant customization of the truck bed. This is where the vacuum pump and high-pressure water systems will be installed. These systems must be securely mounted to avoid any shifting or damage during operation.
     
   • It's important to integrate the vacuum pump to the truck's PTO system or engine so that it can be easily controlled from the truck's cab.
     
3. Debris Tank Mounting
   • The debris storage tank is a key component of the hydrovac system. It is typically mounted on the truck's chassis, with proper bracing and support to handle the weight and pressure of the material being collected.
     
   • Ensure that the tank is large enough to handle the expected amount of material without requiring frequent emptying during operations.
     
4. Hydraulic Boom Installation
   • The boom and hose reel assembly are crucial for directing the water and vacuum systems. Hydraulic lines will be run to the boom, which will be mounted at the rear or side of the truck.
     
   • Operators will need to control the boom for accurate placement of the water jet and suction hose, which may require a sophisticated hydraulic control system.
     
5. Control System Integration
   • The control system for the hydrovac components should be integrated into the cab of the 4700 for easy operation. This will involve wiring for the vacuum pump, water pump, and hydraulic systems.
     
   • A simple and user-friendly interface will ensure that operators can safely and efficiently control the truck.
     
6. Safety and Regulations
   • Converting to a hydrovac truck involves strict adherence to safety and environmental regulations. Ensuring that the system is compliant with local standards for pressure and vacuum systems is crucial.
     
   • Additionally, safety features such as proper seals on the debris tank, pressure relief valves, and emergency shutoff switches should be integrated into the system.
     

Challenges in Conversion

1. Cost: Converting a 4700 truck into a hydrovac unit requires significant investment in parts, labor, and customization. It's important to budget for the additional costs of the conversion and ongoing maintenance.
   
2. Complexity of Installation: While the 4700 truck is sturdy and capable, converting it to a hydrovac requires a significant level of mechanical expertise. Specialized knowledge of hydraulic, vacuum, and water systems is required to ensure everything operates correctly.
   
3. Maintenance and Parts: As a custom-converted vehicle, sourcing parts and performing maintenance could be more difficult than with a factory-built hydrovac truck. Having access to a knowledgeable mechanic familiar with hydrovac systems will be vital for ongoing maintenance.
   

Conclusion
Converting a 4700 truck into a hydrovac vehicle is a viable option for those looking to expand their business or upgrade their equipment. The process involves careful planning, technical expertise, and investment in quality components. By understanding the systems involved and adhering to safety standards, the conversion can result in a powerful and efficient hydrovac truck that can handle a variety of tasks in excavation and utility work.