1. **Select Location**: Choose a suitable location under the truck bed, ensuring there is enough space and clearance from moving parts and the ground. 2. **Gather Tools and Materials**: You will need a drill, drill bits, wrenches, bolts, nuts, washers, measuring tape, and a level. 3. **Measure and Mark**: Measure the dimensions of the truck box and mark the mounting points on the truck frame. Ensure the box will be level and centered. 4. **Drill Holes**: Drill holes into the truck frame at the marked points. Use a drill bit that matches the size of the bolts. 5. **Position the Box**: With assistance, lift the underbody box into position. Align the box’s mounting holes with the drilled holes in the truck frame. 6. **Insert Bolts**: Insert bolts through the mounting holes of the box and the drilled holes in the frame. Use washers to distribute the load evenly. 7. **Secure the Box**: Tighten the nuts onto the bolts using a wrench. Ensure the box is securely fastened and does not move. 8. **Check Alignment**: Use a level to ensure the box is properly aligned and adjust if necessary. 9. **Test Stability**: Gently shake the box to ensure it is stable and securely attached. 10. **Final Inspection**: Double-check all bolts and nuts for tightness and ensure there is no interference with truck components. 11. **Seal and Protect**: Apply a rust-preventive spray or sealant around the drilled holes to prevent corrosion. 12. **Load and Test**: Load the box with items to ensure it holds weight properly and does not sag or shift.

The best materials for underbody truck boxes are aluminum, steel, and stainless steel. Aluminum is lightweight, which helps improve fuel efficiency and is resistant to rust and corrosion, making it ideal for wet or coastal environments. It is also relatively easy to work with, allowing for custom designs and features. However, aluminum can be more expensive than other materials and may not offer the same level of strength as steel. Steel is known for its strength and durability, making it suitable for heavy-duty applications. It can withstand significant wear and tear, providing excellent protection for tools and equipment. Steel is generally more affordable than aluminum but is heavier, which can impact fuel efficiency. It is also prone to rust and corrosion if not properly treated or coated. Stainless steel offers a balance between the benefits of aluminum and steel. It is highly resistant to rust and corrosion, making it suitable for harsh environments. Stainless steel is also strong and durable, providing excellent protection. However, it is typically more expensive than both aluminum and regular steel. When choosing the best material for underbody truck boxes, consider factors such as the environment in which the truck will operate, the weight capacity needed, budget constraints, and the importance of corrosion resistance. Each material has its advantages and trade-offs, so the choice will depend on the specific needs and priorities of the truck owner.

To prevent rust on underbody truck boxes, follow these steps: 1. **Regular Cleaning**: Wash the underbody and truck boxes regularly to remove dirt, salt, and debris. Use a high-pressure hose to reach difficult areas. 2. **Rustproof Coating**: Apply a rustproof coating or undercoating specifically designed for metal surfaces. Products like rubberized undercoating or oil-based sprays can create a protective barrier against moisture and salt. 3. **Galvanization**: Consider using galvanized steel for the truck boxes, as it is coated with a layer of zinc that prevents rust. 4. **Paint Protection**: Use high-quality paint or powder coating on the truck boxes. Ensure the paint is designed for metal surfaces and provides a durable, weather-resistant finish. 5. **Sealant Application**: Apply a sealant to seams and joints to prevent moisture ingress. Silicone or polyurethane sealants are effective for this purpose. 6. **Regular Inspections**: Conduct regular inspections for any signs of rust or damage. Address any issues immediately to prevent further corrosion. 7. **Drainage Maintenance**: Ensure proper drainage to prevent water accumulation. Check and clear any drainage holes or channels regularly. 8. **Storage**: If possible, store the truck in a dry, covered area when not in use to minimize exposure to moisture and harsh weather conditions. 9. **Desiccants**: Use desiccants inside the truck boxes to absorb moisture and reduce humidity levels. 10. **Avoid Road Salt**: Minimize driving on salted roads. If unavoidable, wash the underbody thoroughly after exposure. 11. **Professional Treatment**: Consider professional rustproofing services for comprehensive protection, especially in areas with harsh winters or high humidity. By implementing these measures, you can significantly reduce the risk of rust on underbody truck boxes.

Underbody truck boxes come in a variety of sizes to accommodate different storage needs and vehicle specifications. Common sizes typically range in length from 24 inches to 60 inches, with widths varying from 12 inches to 24 inches, and heights from 12 inches to 18 inches. For smaller trucks or limited space, compact boxes might measure around 24x12x12 inches. Medium-sized options often measure approximately 36x18x18 inches, providing a balance between storage capacity and space efficiency. Larger boxes, suitable for bigger trucks or those requiring more storage, can measure up to 60x24x18 inches or more. These dimensions can vary slightly depending on the manufacturer and specific product line. Custom sizes are also available from some manufacturers to meet unique requirements. It's important to consider the specific dimensions of your truck and the intended use of the box when selecting a size.

1. **Quality Locks**: Use high-quality, tamper-resistant locks such as puck locks or disc locks. These are harder to cut or pick compared to standard padlocks. 2. **Reinforced Latches**: Install reinforced latches that are more resistant to prying and cutting. Consider using latch guards to cover and protect the locking mechanism. 3. **Bolting**: Secure the box to the truck frame using heavy-duty bolts. Use locking nuts or thread-locking compounds to prevent loosening. 4. **Welded Brackets**: Weld brackets to the truck frame and attach the box to these brackets. This makes it more difficult to remove the box without specialized tools. 5. **Alarm System**: Install an alarm system that triggers if the box is tampered with. Some systems can send alerts to your phone. 6. **GPS Tracking**: Equip the box with a GPS tracker. In case of theft, this can help locate the box quickly. 7. **Surveillance Cameras**: Use dash cams or external cameras to monitor the area around the truck. Visible cameras can deter potential thieves. 8. **Parking Strategy**: Park in well-lit, busy areas. If possible, park with the box facing a wall or another vehicle to limit access. 9. **Decals and Warnings**: Place visible warning decals indicating the presence of security systems. This can deter opportunistic thieves. 10. **Regular Checks**: Regularly inspect the box and its security features for signs of tampering or wear. 11. **Insurance**: Ensure the contents of the box are insured. This provides financial protection in case of theft. 12. **Community Watch**: Engage with local community watch programs or trucker networks for added vigilance.