If you're managing a fleet that includes heavy duty trucks, commercial vehicles, or buses, then you know how crucial it is to ensure these vehicles' air brake system is working at optimal capacity. The air brake system is responsible for slowing the vehicle down and putting it to a complete stop. So when it fails, it can put your driver's safety and the safety of those around the vehicle at risk. To prevent this from happening, make sure to perform regular air brake maintenance and inspection—and one of its most critical components that must be checked is the spring brake. 

What is a spring brake?

The spring brake, which is normally found on the rear axle of heavy duty trucks, is used for the air brake's emergency and parking brake systems. This type of brake was developed as a safety measure. Before the use of spring brakes, a heavy duty truck that had lost air pressure due to a hose or system failure had no way of coming to a controlled stop immediately. To resolve this problem, vehicle manufacturers started equipping their vehicles with spring brakes.

The spring brake has two air chambers: one to release the spring and another to apply braking power. Inside the chamber is a powerful spring with about 2,500 pounds of pressure behind it. A steady and constant airflow in the chamber holds back that spring. When air pressure is not applied to the chamber, the spring acts as a parking brake or an emergency brake. 

How does the spring brake work?

To activate the parking brakes, the driver must pull out one or both of the valves on the dash. The dash button releases the air holding back the spring, putting the vehicle to a safe stop. The emergency brakes, on the other hand, deploy automatically if the air brake system fails and there's not enough air in the system to hold the spring back. 

But, you don’t have to wait for the spring brakes to engage the emergency brakes automatically when the air pressure drops below 60 psi. Once you notice the low-pressure light comes on and a buzzer goes off, you should bring the vehicle to a safe stop immediately while you can still control the emergency brakes. Doing this can help prevent any untoward incident that may arise from improperly adjusted spring brakes. 

If you need to move your truck and there is no air pressure to release the spring, a cage bolt is required. You see, spring brakes come with a way to mechanically release the spring tension. Simply insert a cage bolt into the spring brake chamber and tighten it until the brake releases. Once you have moved your truck to your desired location, remove the bolt and wait until the parking brake has been reset. 

Why choose the Haldex Maxibrake® HR-Series spring brake?

When it comes to reliable emergency braking and parking, nothing does it better than Haldex Maxibrake® HR-Series spring brake. This is an air/hydraulic pull-type spring brake that applies the emergency/parking brakes when the air pressure falls to the manufacturer's specification, which is 20 to 40 psi.

Listed below are some of its features and benefits:

• Made with an all-steel housing for maximum strength and superior durability
• Engineered with nylon bearings and steel piston that provide great guidance stability, allowing it to diffuse twisting and lateral motion
• Offers added corrosion resistance as it comes with epoxy-coated steel alloy springs
• Built to offer longer service life and uniform output with its deeper spring cavities and optional spring force outputs
• Ensures the vehicle cannot be moved until the air pressure is at the right level
• Manufactured to meet the highest quality standards
• Goes through rigorous testing to ensure maximum efficiency and reliability

Any useful tips when replacing the spring brake?

Spring brakes are crucial air brake system components for emergency situations, so make sure to replace them when they get damaged. However, replacing a spring brake is a task that’s better handled by professional mechanics. 

If you do have the knowledge in replacing the spring brake and are confident in doing it yourself, make sure to keep these tips in mind before you start with the actual replacement process:

• Make sure to block the vehicle’s wheels to prevent it from rolling away and causing possible bodily harm.
• If you notice structural or physical damage to the spring brake, do not attempt to service it. It’s highly recommended that you replace the entire unit instead of doing a temporary fix. 
• Cut the service push rod with a use of a blow torch when removing a damaged spring brake. This can help release any excess force that might have built up. 
• Be extra cautious when handling the spring brake chamber. Do not strike it, and never let it fall because this can cause damage to its mechanical structure. 
• If the emergency diaphragm on the spring brake chamber already needs replacement, then replace the entire piggyback instead. 
• Position your body to the side when replacing a spring brake. 

Where to get the Haldex spring brake? 

Haldex has a wide network of distributors worldwide. For your shopping convenience, you can always get the Haldex spring brake here at FinditParts, your one-stop shop for hard-to-find truck and trailer parts and accessories. We also offer a large selection of other Haldex parts, including automatic brake adjusters (ABA), actuators, air disc brakes, air dryers, compressors, valves, brake shoes, and more. 

FinditParts is available 24 hours a day, 7 days a week. Simply check the Haldex Maxibrake® HR-Series spring brake here or use our quick lookup feature if you need other Haldex products. To place an order, just add the item/s to your cart or contact our customer service team for assistance. 

About the manufacturer

Haldex is a global supplier of innovative vehicle solutions that improve safety, vehicle dynamics and environmental sustainability in the commercial vehicle industry. It is headquartered in Sweden, but it operates worldwide with production facilities in Sweden, Brazil, China, Germany, Mexico, India, Hungary, and the United States. Despite its continued success, Haldex remains true to its mission, and that is to create a world of safer vehicles through reliable truck braking systems, innovative vehicle solutions, and excellent customer service.