The HAS 402 suspension system is a popular aftermarket upgrade for off-road vehicles, designed to improve articulation, ride comfort, and ground clearance. If you're researching the HAS 402 suspension parts list, you likely want to know exactly what components are included, how they work, and what to consider before installing. This article provides a thorough breakdown of each part, its function, and practical advice for choosing and maintaining your suspension.
What Is the HAS 402 Suspension System?
The HAS 402 is a complete suspension kit engineered for high articulation and durability in off-road conditions. It is commonly used on midsize trucks and SUVs, such as the Toyota Tacoma, 4Runner, and similar platforms. The "402" indicates a specific valving or spring rate configuration optimized for a balance of on-road comfort and off-road performance. The parts list includes all necessary components to replace the factory suspension front and rear.
Front Suspension Components
Shock Absorbers
The front shocks in the HAS 402 kits are typically remote-reservoir or piggyback-style units, offering high heat dissipation and consistent damping on rough trails. They feature adjustable compression and rebound damping, allowing you to fine-tune the ride for different terrains. The shock body is often made of aluminum for corrosion resistance, and the shafts are hardened steel.
Coil Springs
Front coil springs are designed to support the vehicle's weight while providing increased travel. They are usually progressive-rate or dual-rate, meaning the spring stiffness increases as it compresses. This helps maintain a comfortable ride on pavement while offering resistance during heavy off-road use. The springs are matched to the shock valving to prevent bottoming out.
Upper Control Arms (UCAs)
To accommodate larger tires and correct suspension geometry after lifting, the HAS 402 includes reinforced upper control arms. These are built with heavy-duty ball joints and polyurethane bushings that allow for increased droop and prevent binding. Proper UCAs also restore factory caster angles, improving steering response and reducing bump steer.
Lower Control Arms
In some configurations, the lower control arms are upgraded to include additional bracing or relocation brackets. They provide a stronger pivot point for the knuckle and help maintain proper alignment specs after a lift. The bushings may be replaced with high-angle units.
Sway Bar Links
Quick-disconnect or adjustable sway bar links are part of the front suspension kit. Disconnecting the front sway bar off-road increases articulation, allowing the suspension to move independently over obstacles. The links are often greasable for long-term maintenance.
Steering Stabilizer
A heavy-duty steering stabilizer is included to reduce bump steer and dampen vibrations from large tires. It mounts along the tie rod and works like a shock absorber for the steering system.
Rear Suspension Components
Shock Absorbers
Rear shocks are similarly valved and often feature a larger bore to handle the vehicle's weight. They are mounted with a stem or loop end, and may include a remote reservoir to reduce fade on extended descents.
Coil Springs
The rear coil springs are designed to support the payload and maintain ride height. For trucks with leaf spring conversions, the kit may include a coil-over conversion. The springs are matched to the shocks for a balanced ride.
Leaf Springs (if applicable)
Some HAS 402 kits replace the factory leaf springs with a progressive leaf pack or add-a-leaf for increased load capacity. This improves stability when carrying gear or towing. The leaf springs are zinc-coated for rust protection.
Track Bar or Panhard Rod
A rear track bar is included to center the axle under the vehicle and prevent side-to-side movement during articulation. It mounts to the frame and axle housing, often with a polyurethane bushing for noise isolation.
Bump Stops
Hydraulic or foam bump stops are added to prevent the suspension from bottoming out on hard impacts. They provide progressive resistance and protect the shocks and springs from damage.
Hardware and Installation Components
Mounting Brackets
The HAS 402 kit includes all necessary mounting brackets for shock reservoirs, sway bar disconnects, and track bars. These are laser-cut and powder-coated for durability.
Bushings and Sleeves
Replacement bushings (polyurethane or OEM-style rubber) are provided for control arms and sway bar links. Grease fittings allow for periodic lubrication.
Fasteners
Grade 8 bolts, nuts, and washers are included to ensure safe installation. Some kits require reusing factory hardware for certain connections.
Instructions
A detailed instruction manual with torque specs and step-by-step guidance is part of the package. It covers removal of factory parts, installation sequence, and alignment recommendations.
Compatibility and Important Considerations
Vehicle Fitment
Before purchasing a HAS 402 suspension, verify that it fits your exact vehicle model and year. Most kits are designed for a specific lift height (e.g., 2-3 inches front, 1-2 inches rear). Cross-referencing with the manufacturer's fitment chart is essential.
Tire Size Limitations
The parts list assumes a maximum tire size, often 33 inches or 35 inches depending on the lift height. Exceeding this may require additional modifications such as trimming the fenders or installing aftermarket bumpers.
Alignment Requirements
After installation, a professional alignment is necessary to set camber, caster, and toe. The upper control arms allow for adjustment, but some shops may need special tools for lifted trucks.
Maintenance and Longevity
Inspect all bushings and ball joints every 5,000 miles or after heavy off-road use. Grease all fittings and check bolt torque periodically. Shocks may need rebuilding after extended use.
Practical Recommendation: What to Look For in a Suspension Kit
When evaluating the HAS 402 suspension parts list, consider these factors to ensure you get the best setup for your needs:
- Terrain Type: If you mostly run rock crawls, prioritize articulation and shock travel. For desert running, look for bypass shocks and progressive springs.
- Load Capacity: If you carry a heavy bumper, winch, or rooftop tent, choose a kit with higher spring rates.
- Adjustability: Features like adjustable damping and ride height allow you to fine-tune the suspension for different conditions.
- Brand Reputation: Stick with manufacturers that offer warranties and replacement parts easily.
- Installation Complexity: Some kits require welding or drilling; others are bolt-on. Be honest about your skill level.
A well-chosen HAS 402 suspension will transform your off-road experience, but only if the parts list matches your driving style and vehicle. Take the time to understand each component's role, and don't hesitate to consult a professional installer for guidance.