PSI To Apply Spring Brakes

Spring Into Action

Long-haul trips can be stressful. You will encounter your fair share of irritating drivers as well as unwelcomed weather elements and undesirable road conditions, and with all these challenges, there may be a time when you need to pump the brakes - and fast. Therefore, it is important that your heavy- duty truck is equipped with reliable spring brakes plus enough air pressure.

What Are Spring Brakes?

Slowly count to five. That is the number of seconds it takes the average semi truck to stop roughly 450-500 feet on regular road speeds in good conditions. That is a long time especially when in a panic situation. Newer vehicles, be it a car, SUV or large fleet truck, are equipped with emergency and parking brake systems using – modern technology. on heavy trucks are found on the rear axle but work differently than traditional service brakes on most passenger vehicles.

How Do Spring Brakes Work?

Instead of fluid from to apply pressure, spring brakes use air to slow down vehicles. Spring brakes work internally inside a braking chamber to apply the braking power. The brake chamber contains a [rubber] diaphragm, a metal pushrod, and a powerful return coil spring that works its magic to help trucks come to a complete stop. Spring brakes are applied when air pressure leaves the brake chamber. When the driver is ready to release the brake, air refills the braking chamber and opposes the spring force. With that in mind, the right amount of air pressure (PSI) must be considered for parking and emergency brakes to engage.

Why PSI Matters

As you know, heavy trucks take longer to stop, and they rely on spring brakes to help them come to a controlled pause. Parking and emergency brakes on straight trucks will come on when the spring is decompressed at 20 to 45 PSI, and since vehicles can drive with spring brakes on, the brake system should have at least 60 pounds of PSI. Large buses, such as community and school buses, may see low pressure warning signals at 80-85 PSI. Remember, pressing and releasing the brake pedal too many times will let air out faster and take longer for the compressor unit to replace. If the vehicle does not have enough air pressure in the tank, spring brakes will remain engaged and the vehicle may not move.

Spring Brake Maintenance Tips

Now that you understand how spring brakes work, you may be asking how should I know when my spring brakes are bad, and when should I replace them? Generally, most spring brake pads will last about 25,000-65,000 miles on semi-trucks; however, it is safe to say that you should consider replacing them around 40,000 miles. Cracks and chips in the brake chamber may not always be visibly present, butsmall leaks should be checked near the diaphragm to give you a better idea whether the braking system is damaged. You can drive with a busted spring brake system, butof course, it is not recommended for long journeys. Doing so will affect other components of the truck, including the rear suspension system, and can throw off the weight distribution on one corner of the truck. Rear tires and axles will feel the impact and cause the truck to become misaligned. Most importantly, broken springs will put other drivers in danger if you cannot properly stop your vehicle in time. Our point? Fix spring brakes when air leaks or when you hit the suggested mileage.

When you need reliable aftermarket spring brakes for your heavy-duty vehicle, turn to a reputable brand you can trust, such as , to safeguard your truck and yourself.