1. Product Overview
This manual provides essential information for the proper installation, operation, and maintenance of your TORQUE Trailer Air Spring Bag, model TR8709. This air spring is designed as a replacement for various OEM parts, including Firestone 8709, 8751, W01-358-8709, and Goodyear 1R13-159, specifically for Hendrickson AAT 23K Models Intraax & Van Traax.
Image 1.1: Bottom view of the TORQUE TR8709 Trailer Air Spring Bag, displaying the engraved part number and final inspection sticker.
2. Important Safety Information
Image 2.1: Safety warning regarding correct part number verification.
WARNING: Before purchasing or installing this product, it is critical to verify the correct part number for your specific vehicle. Consult your dealer and provide your Vehicle Identification Number (VIN) to ensure compatibility. Installing an incorrect air spring can lead to premature failure, potentially causing a blowout during operation and resulting in a serious accident. Always prioritize safety and proper fitment.
- Ensure the vehicle is properly supported and secured before beginning any installation.
- Always deflate the air suspension system completely before removal or installation.
- Wear appropriate personal protective equipment (PPE), including safety glasses and gloves.
- Refer to the vehicle manufacturer's service manual for specific torque specifications and procedures.
3. Product Specifications
| Specification | Detail |
|---|---|
| Model Number | TR8709 |
| Extended Height | 19.40 inches |
| Compressed Height | 6.00 inches |
| Top Plate Width | 10.38 inches |
| Piston Width | 9.15 inches |
| Item Weight | 14.00 lbs |
| Rubber Thickness | 4.5 - 5.00 mm (exceeds OEM) |
| Stud Material | 4140 grade steel (25% stronger) |
| Piston Type | Stronger composite pistons |
| OEM Part Number Replacements | Firestone 8709, 8751, W01-358-8709, W01-358-8751; Goodyear 1R13-159; Hendrickson S-20900, S-21800, C-20900, C-21800; Triangle AS-8453, AS-8460; Automann AB1DK25B-8751, 566.ER8709; Sampa SP558709-KP |
Image 3.1: Dimensional diagrams of the air spring, showing side and top views with key measurements.
Image 3.2: Internal structure comparison illustrating the quality features of TORQUE air springs.
4. Fitment and Compatibility
This air spring is designed to replace specific OEM parts for Hendrickson AAT 23K Models Intraax & Van Traax. It is crucial to verify compatibility before installation.
4.1. Verification Process
- Consult Your Dealer: Contact your vehicle dealer and request the correct part number for your specific application, providing your Vehicle Identification Number (VIN).
- Cross-Reference: Compare the OEM part number provided by your dealer with the list of replacement part numbers for the TR8709 model (listed in Section 3).
- Match Specifications: Carefully review the dimensional diagrams (Image 3.1) and specifications (Section 3) to ensure they match your existing air spring or the requirements for your vehicle.
Important Note: Purchasing an air spring solely based on vehicle make and model is a common error. Always confirm the specific part number and dimensions to prevent fitment issues and potential product failure.
5. Installation Instructions
Installation of air springs should be performed by qualified personnel with appropriate tools and safety equipment. Refer to the vehicle manufacturer's service manual for detailed, vehicle-specific procedures.
5.1. Pre-Installation Steps
- Vehicle Preparation: Park the vehicle on a level, stable surface. Engage the parking brake.
- Secure Vehicle: Use jack stands or other appropriate lifting equipment to safely support the vehicle frame, ensuring the suspension is fully extended and the wheels are off the ground.
- Deflate System: Completely deflate the air suspension system by releasing air pressure from the air lines connected to the air springs.
- Disconnect Air Lines: Carefully disconnect the air lines from the existing air spring.
- Remove Fasteners: Remove the bolts or nuts securing the top and bottom plates of the old air spring to the vehicle chassis and axle.
5.2. Air Spring Removal
- Once all fasteners and air lines are disconnected, carefully remove the old air spring from its mounting location. Note its orientation for reference during new installation.
5.3. New Air Spring Installation
- Position New Spring: Place the new TORQUE TR8709 air spring into the mounting location, ensuring correct orientation.
- Secure Top Plate: Attach the top plate of the air spring to the vehicle frame using the appropriate fasteners. Hand-tighten initially.
- Secure Bottom Plate: Attach the bottom plate of the air spring to the axle or suspension component. Hand-tighten initially.
- Connect Air Lines: Reconnect the air lines to the air spring's air inlet port. Ensure a secure, leak-free connection.
- Torque Fasteners: Refer to the vehicle manufacturer's specifications for the correct torque values for all fasteners. Tighten all bolts and nuts to the specified torque.
5.4. Post-Installation Check
- Inflate System: Slowly inflate the air suspension system to the recommended operating pressure.
- Check for Leaks: Use a soapy water solution to check all air line connections and the air spring itself for any air leaks. Bubbles indicate a leak.
- Lower Vehicle: Carefully lower the vehicle from the jack stands.
- Final Inspection: Visually inspect the installed air spring and surrounding components for proper clearance and function.
Image 5.1: Example of an air suspension component, such as a valve or fitting, which may be part of the installation process.
6. Operating Instructions
The TORQUE Trailer Air Spring Bag operates as a critical component of your vehicle's air suspension system, providing support and damping for the trailer load. Proper operation relies on maintaining correct air pressure.
6.1. Air Pressure Management
- Recommended Pressure: Always operate the air suspension within the vehicle manufacturer's recommended air pressure range. This range is typically found in the vehicle's owner's manual or service documentation.
- Load Adjustment: Adjust air pressure according to the load being carried. Heavier loads generally require higher air pressure to maintain ride height and stability.
- Avoid Over-inflation/Under-inflation:
- Over-inflation can lead to a harsh ride, reduced traction, and premature wear of suspension components.
- Under-inflation can cause excessive suspension travel, bottoming out, and potential damage to the air spring or other suspension parts.
- Monitoring: Regularly monitor the air pressure using a reliable gauge, especially before and during long hauls.
6.2. Ride Height Control
The air spring works in conjunction with the vehicle's leveling valves to maintain a consistent ride height, regardless of load. Ensure the leveling valve system is functioning correctly for optimal performance.
7. Maintenance
Regular inspection and maintenance are crucial for extending the lifespan and ensuring the reliable performance of your TORQUE air spring.
7.1. Routine Checks
- Visual Inspection: Periodically inspect the air spring for any signs of wear, cracks, abrasions, or damage to the rubber bellows. Check for corrosion on the metal components (top plate, piston, studs).
- Air Leak Detection: Regularly check for air leaks using a soapy water solution on all air line connections and the surface of the air spring, especially after significant temperature changes or heavy use.
- Fastener Tightness: Verify that all mounting bolts and nuts are securely tightened to the manufacturer's specifications.
- Clearance: Ensure there is adequate clearance around the air spring, and no components are rubbing against it.
- Air System Components: Inspect air lines, leveling valves, and air tanks for damage, leaks, or proper function.
7.2. Cleaning
- Clean the air spring and surrounding area regularly to remove dirt, debris, and road salt, which can accelerate wear and corrosion. Use mild soap and water. Avoid harsh chemicals or solvents.
8. Troubleshooting
This section addresses common issues that may arise with air springs and provides general troubleshooting steps. For complex issues, consult a qualified technician.
8.1. Common Problems and Solutions
| Problem | Possible Cause | Solution |
|---|---|---|
| Air spring deflates or loses pressure rapidly. | Air leak in the air spring, air line, or fittings. Faulty leveling valve. | Inspect for leaks using soapy water. Tighten connections. Replace damaged components. Check leveling valve function. |
| Vehicle ride height is incorrect (too high/low). | Improper air pressure. Faulty leveling valve. Obstruction in leveling valve linkage. | Adjust air pressure. Inspect and adjust/replace leveling valve. Clear any obstructions. |
| Air spring appears damaged (cracks, bulges). | Physical damage, age, over-inflation, or rubbing against other components. | Replace the air spring immediately. Investigate cause of damage to prevent recurrence. |
| Excessive vibration or harsh ride. | Over-inflation. Worn shock absorbers. Misaligned suspension. | Check and adjust air pressure. Inspect and replace shock absorbers if necessary. Check suspension alignment. |
9. Warranty and Support
9.1. Product Warranty
TORQUE offers an industry-leading 3-year unlimited mile warranty on its rolling lobe / reversible sleeve air springs, including model TR8709. This warranty covers defects in materials and workmanship under normal use and service.
To activate and register your product warranty, please visit the official Torque Parts website after receiving your air spring. Retain your proof of purchase for warranty claims.
9.2. Customer Support
For technical assistance, warranty claims, or further inquiries, please contact Torque Parts customer support. Contact information can be found on the official Torque Parts website.
Online Resource: Visit the Torque Store on Amazon
