Hendrickson SURELOK Ride Height Lock User Manual

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Hendrickson SURELOK Ride Height Lock: Complete Product Manual

Introduction to the Hendrickson SURELOK Ride Height Lock

The Hendrickson SURELOK Ride Height Lock is a pneumatically controlled trailer support system designed to maintain a consistent trailer floor height during loading and unloading. Its mechanical support arms engage with the suspension beams, helping reduce trailer movement, trailer drop, and dock walk during dock operations.

SURELOK automatically engages when the trailer parking brakes are applied and retracts when the parking brakes are released. This automatic operation reduces driver interaction and helps create a more consistent loading environment. The system may also be used in place of a dump valve on compatible applications to limit trailer walk and drop.

This ride height lock is intended for fleets, terminal operators, trailer technicians, and drivers who need improved trailer stability at loading docks. It is particularly useful on trailers equipped with compatible Hendrickson air suspensions, including certain slider suspension systems and other approved suspension configurations.

Correct suspension ride height is essential for reliable operation. When properly installed and adjusted, the SURELOK system supports efficient dock operations while helping protect loading equipment and improve workplace safety. Always confirm the correct kit, suspension model, operating procedure, and ride-height setting before installation or service.

Hendrickson SURELOK Ride Height Lock Specifications

Product type: Pneumatically controlled mechanical trailer support and ride height locking system.
Primary function: Maintains trailer height during loading and unloading.
Support mechanism: Locking support arms engage directly with the trailer suspension beams.
Activation: Automatically engages when the trailer parking brake is set.
Release: Automatically retracts when the trailer parking brake is released, provided the suspension reaches the required height.
Stability benefit: Helps minimize trailer movement, dock walk, and trailer drop during loading activity.
Compatibility: Available for selected Hendrickson trailer suspensions and approved air-control configurations. The correct kit must match the suspension model, beam arrangement, air actuator, and designed ride height.
Ride-height requirement: Operation depends on the suspension being set as close as possible to its designed ride height.
Control options: Configurations may include an override or dump valve for approved applications, including non-over-the-road transport procedures.
Service requirement: Installation, adjustment, welding, and air-system checks should be performed by qualified trailer technicians.

How to Install and Set Up the SURELOK Ride Height Lock

Installation varies by suspension model and SURELOK kit. Use the applicable Hendrickson installation procedure and verify kit compatibility before beginning.

Park the trailer on a level, debris-free surface, apply the parking brakes, and chock the wheels.
Exhaust the trailer suspension air and confirm that the suspension is safely supported before working beneath the trailer.
Identify the suspension model and confirm that the selected SURELOK assembly is correct for the beam, actuator, and trailer configuration.
Install the roadside and curbside brackets using the supplied hardware and the specified mounting locations.
Attach the support-arm springs and position the SURELOK assembly against the trailer frame as directed by the installation procedure.
Temporarily clamp the assembly, verify all required measurements, and complete approved welding or fastening procedures.
Recharge the air tank and suspension air springs, then inspect every air line and connection for leaks.
Check the designed ride height and adjust the height-control system if necessary.
Apply the parking brake and visually confirm that both support arms engage correctly above the suspension beams.

Keep hands, tools, and clothing away from the support arms and suspension beams. Never transport a trailer by rail or another non-road method with SURELOK engaged; use the approved override or dump-valve procedure and exhaust the suspension air springs.

SURELOK Troubleshooting and Maintenance Guide

Support arms do not engage

Set the trailer parking brake, confirm adequate air pressure, and inspect the control circuit for leaks or damaged lines. Verify that the suspension is at the correct ride height and that the arms are not obstructed by debris, damaged components, or incorrect mounting.

Support arms do not retract

Release the parking brake and allow the height-control valve to raise the trailer sufficiently for the arms to clear the suspension beams. Do not force the arms manually. Inspect the air supply, override valve, springs, brackets, and arm movement if the system remains engaged.

Trailer height changes during loading

Check the designed ride height, height-control valve operation, air-spring condition, and support-arm alignment. Incorrect ride height can reduce the system’s ability to limit trailer drop or prevent proper engagement.

Air leak or damaged hardware

Apply an approved leak-detection solution to accessible fittings and connections, then repair leaks before returning the trailer to service. Replace bent, cracked, excessively worn, or corroded components with approved parts.

No universal electronic error-code system applies to every SURELOK configuration. Record the trailer number, suspension model, symptoms, air pressure, and ride-height measurement when requesting assistance. For operating, maintenance, or service support, contact Hendrickson through its official trailer support channels or call 1-855-RIDE-RED. Consult the applicable operator and installation manuals for warranty procedures and model-specific requirements.

Pros and Cons of the Hendrickson SURELOK Ride Height Lock

Advantages

Automatic operation: Engagement and release are linked to the trailer parking brake, reducing routine driver input.
Improved dock stability: Mechanical support arms help maintain trailer floor height during loading and unloading.
Reduced trailer movement: The system helps limit dock walk and trailer drop compared with an air suspension operating without a mechanical height lock.
Fleet-friendly design: Approved configurations are available for selected Hendrickson suspensions and air-control systems.
Practical safety benefit: A stable trailer can make dock loading more predictable when the system is correctly installed and operated.

Limitations

Model-specific compatibility: The correct kit must match the suspension model, beam design, and ride-height specification.
Installation complexity: Bracket positioning, measurement, welding, and air-system verification may require qualified technicians.
Ride-height sensitivity: Incorrect height settings can prevent full engagement or reduce trailer stabilization.
Maintenance requirements: Air leaks, damaged springs, contaminated mechanisms, and worn brackets require inspection and repair.
Best suited for: Fleets and operators that frequently load or unload air-suspension trailers at docks.
May not suit: Applications without a compatible Hendrickson suspension or users seeking a universal, non-model-specific installation.

Safe Operating Checklist

Park on a level surface whenever possible.
Apply the trailer parking brake and chock the wheels before loading or unloading.
Visually confirm that both SURELOK support arms are engaged.
Stay clear of suspension components and support arms during engagement and release.
Do not operate with damaged brackets, leaking air lines, or misaligned support arms.
Use the approved override or dump-valve procedure before non-over-the-road transport.
Follow the exact Hendrickson operator manual and installation procedure for the installed suspension model.

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Faqs

How do I set up the hendrickson SURELOK Ride Height Lock for the first time?

Installation should match the exact Hendrickson suspension model and SURELOK kit. Park the trailer on a level, debris-free surface, apply the parking brake, and chock the wheels before work begins. A qualified technician should mount the support assembly, connect the actuator and air lines, set the suspension to its designed ride height, and check every connection for leaks. Confirm that both support arms engage and retract fully before returning the trailer to service.

How does the hendrickson SURELOK Ride Height Lock engage and disengage?

In the typical automatic configuration, SURELOK support arms engage when the trailer parking brake is applied and retract when the parking brake is released. Before loading or unloading, apply the parking brake, chock the wheels, and visually confirm that both arms are positioned over the suspension beams. Before moving the trailer, remove the chocks, release the parking brake, and verify that both arms are completely clear of the suspension.

What should I do if the hendrickson SURELOK Ride Height Lock will not engage?

First secure the trailer by applying the parking brake and chocking the wheels. Check whether the suspension is at its designed ride height, because an incorrect height can prevent the support arms from aligning correctly. Inspect the air supply, lines, fittings, actuator, and arm assembly for damage, leaks, obstruction, or frozen movement. Do not force the arms by hand. If the system still will not engage, keep the trailer out of service until a qualified technician inspects it.

Why is the hendrickson SURELOK Ride Height Lock not holding trailer height during loading?

SURELOK performance depends primarily on the trailer suspension operating at its specified designed ride height. Excessive ride height can reduce the system’s ability to limit trailer drop or walk, while insufficient ride height can stop the support arms from engaging properly. Confirm the suspension height using the applicable Hendrickson procedure, then inspect both arms for correct positioning, wear, bending, or interference. Also check for air leaks and verify that the parking-brake control operates the system correctly.

Can the hendrickson SURELOK Ride Height Lock be used with every trailer suspension?

No. SURELOK kits are matched to particular Hendrickson suspension models, suspension beams, air actuators, and mounting arrangements. Do not assume that a kit designed for one suspension fits another, even when the trailers appear similar. Identify the suspension model and consult the applicable Hendrickson installation documentation before ordering parts or beginning installation. If the model or kit is uncertain, obtain confirmation from a Hendrickson service representative or qualified trailer technician.

Can I use the hendrickson SURELOK Ride Height Lock when transporting a trailer by rail or another method?

SURELOK must be disengaged when the trailer is transported by a method other than normal over-the-road travel, and the suspension air springs must be exhausted. Use the trailer’s approved override or dump-valve procedure when equipped. Follow all loading and securement requirements for the transport method, and never work near the support arms without first securing the trailer against movement. The operating configuration for dock loading is not automatically suitable for rail or other transport.

How can I reduce dock walk with the hendrickson SURELOK Ride Height Lock?

Dock walk is minimized when the SURELOK locking legs are fully engaged and the trailer suspension remains at its designed ride height. Park on a suitable surface, apply the trailer parking brake, chock the wheels, and visually confirm that both support arms sit directly above the suspension beams. Avoid loading if one arm is retracted, misaligned, or obstructed. Correct any ride-height, air-supply, or mechanical problem before continuing, rather than relying on partial engagement.

What maintenance does the hendrickson SURELOK Ride Height Lock require?

Inspect SURELOK during routine trailer maintenance and whenever the trailer has loading or ride-height problems. With the trailer secured, examine the support arms, brackets, springs, actuator, pins, air lines, and fittings for looseness, corrosion, deformation, wear, or leaks. Verify that the arms move through their complete engaged and retracted positions without interference. Check the suspension ride height against the applicable specification. Use only approved replacement parts and have damaged components repaired before operation.