Complete Guide to Hendrickson Air Suspension Parts: Selection, Maintenance, and Buying Tips

Hendrickson is a leading manufacturer of heavy-duty truck and trailer suspension systems. Their air suspension designs are known for durability, ride quality, and load capacity. When it comes to replacing or upgrading parts, understanding the components and their functions is essential. This guide covers the most common Hendrickson air suspension parts, how to select the right ones, and maintenance practices to keep your system running smoothly.

Understanding Hendrickson Air Suspension Systems

Hendrickson offers several air suspension series for trucks and trailers, including the HAS, INTRAAX, HTB, and others. Each series has specific parts designed to work together. Before buying any replacement parts, identify your suspension model and year. The model number is usually stamped on a tag attached to the suspension frame or axle. Knowing this will ensure compatibility.

Air suspension systems use compressed air to support the vehicle’s weight and absorb road shocks. Key components include air springs, shock absorbers, height control valves, leveling valves, and various bushings and brackets. Failures in any of these parts can reduce ride quality, cause uneven tire wear, or lead to system leaks.

Common Hendrickson Air Suspension Parts and Their Functions

Air Springs / Air Bags

Air springs, often called air bags, are the primary load-carrying components. Hendrickson uses robust rubber bellows or rolling lobe designs. Over time, rubber can crack or develop leaks from road debris, ozone, or age. Symptoms of a failing air spring include the vehicle sitting unevenly, frequent compressor cycling, or visible cracking. When replacing, match the exact part number from the manufacturer. Aftermarket options are available but verify they meet OEM specifications.

Shock Absorbers

Shock absorbers control spring oscillations and dampen vibrations. Worn shocks lead to excessive bouncing, poor handling, and increased wear on other suspension parts. Hendrickson systems often use standard commercial shocks that are relatively easy to replace. Choose a shock rated for the vehicle’s gross vehicle weight rating (GVWR) and intended use, such as on-highway or off-road.

Height Control Valves

Height control valves (HCVs) regulate the air pressure in the air springs to maintain a constant ride height, regardless of load. Hendrickson uses mechanical leveling valves that sense chassis height and add or release air as needed. A faulty HCV can cause the suspension to be too high or too low, affecting alignment and safety. Symptoms include the vehicle sitting unevenly or the compressor running continuously. Clean the linkage and check for binding before replacing the valve.

Leveling Valves

Leveling valves are similar to HCVs but often control multiple air springs or axle groups. They ensure the vehicle remains level under varying loads. Common issues include corrosion, stuck linkages, or failed internal seals. Replacement is straightforward, but it is critical to adjust the linkage correctly after installation. Improper adjustment can cause drivability problems.

Bushings and Pivot Points

Hendrickson suspensions have multiple pivot points with rubber or polyurethane bushings. These allow controlled movement while isolating vibration. Worn bushings produce clunking noises, imprecise handling, and uneven tire wear. Inspect them during routine maintenance. Press-in bushings require a special tool for replacement. Consider upgrading to heavy-duty or polyurethane for longer life in severe applications.

Air Lines and Fittings

Air lines deliver compressed air from the tank to the air springs. They can rub against frame rails or corrode, especially in salt-belt states. Look for chafing, cracks, or loose fittings. Use nylon or DOT-approved tubing. Replace any damaged lines and ensure connections are tight. Leaks are a common source of suspension problems – a simple soapy water test can locate them.

How to Choose the Right Hendrickson Air Suspension Parts

Identify Your Suspension Model

First, locate the model tag on the suspension. It will list the series (e.g., HAS-190A, INTRAAX AAT, HTB-230). Write down the part number for the component you need. If the tag is missing, contact Hendrickson with your vehicle VIN or visit their website for cross-reference guides. Using the wrong part can compromise safety and performance.

Check OEM Specifications

Always verify specifications such as spring rate, stroke length, shock damping, and air pressure range. For air springs, note the collapsed and extended heights, as well as the diameter and mounting type. For shocks, the extended and collapsed lengths, and bushing sizes must match. Hendrickson’s official catalog or a trusted distributor can provide this data.

Consider Aftermarket vs. OEM

OEM parts are guaranteed to fit and perform exactly as the original. However, aftermarket parts from reputable brands can offer cost savings and sometimes improved durability. Be cautious with unknown brands, especially for air springs and valves where quality varies. For critical components like height control valves, OEM is often recommended. For bushings or air lines, aftermarket options are generally fine.

Maintenance Tips for Hendrickson Air Suspension

• Perform visual inspections every oil change. Look for cracks in air springs, leaks at fittings, and worn bushings.
• Listen for air leaks. If the compressor runs more than normal, suspect a leak. Use a spray bottle with soapy water to check all connections, valve bodies, and air spring bellows.
• Keep the system clean. Dirt and road grime can accelerate seal wear. Wash under the vehicle periodically, especially after off-road or winter driving.
• Check ride height regularly. If the vehicle sits unevenly, adjust the height control valve linkage or replace if faulty. Incorrect height stresses driveline components and reduces tire life.
• Replace shocks at the same time on both sides of an axle to maintain balanced damping. Typically, shocks should be replaced every 50,000–100,000 miles depending on use.
• Lubricate pivot points as recommended. Some bushings are greasable; use a high-quality chassis grease. For non-greasable ones, replace when they develop play.

Where to Buy Hendrickson Air Suspension Parts

The best sources are authorized Hendrickson distributors or direct from the manufacturer. Many heavy-duty truck parts suppliers stock Hendrickson components. Online catalogs from reputable suppliers allow you to search by part number. Local heavy-duty repair shops can also source parts and may offer installation if needed. When ordering, always confirm the part is genuine or from a trusted aftermarket brand. Avoid unknown sellers offering suspiciously cheap parts – quality and safety should come first.

Final Recommendation

For routine replacements like air springs, shocks, and bushings, choose parts that meet OEM specifications. For height control valves and leveling valves, stick with OEM Hendrickson parts for reliability. Keep a log of parts replaced and mileage to predict future needs. Establish a relationship with a local heavy-duty parts supplier that stocks Hendrickson components. With proper selection and maintenance, your Hendrickson air suspension will deliver years of dependable service and a smoother ride.