How to Fix an Air Leak on a Truck

Trucks are an essential part of Australia’s transportation and commerce industries. These vehicles travel millions of kilometres in some of the world’s harshest conditions, and that means little issues like air leaks can quickly become a serious problem. Air leaks not only reduce braking performance, they can lead to issues like reduced fuel efficiency and increased wear on vital components. If you want to avoid being stuck on the side of the road, it’s important to invest in regular brake maintenance. In this article our mobile diesel mechanics will look into air leaks in more detail and some of the common causes you might encounter.

How Do Air Brakes Work?

Most cars and passenger vehicles use a hydraulic braking system. Hydraulic brakes are simple, cost-effective and compact, but they’re not suitable for heavy vehicles that require significant stopping force. Instead, trucks and heavy vehicles use compressed air to transmit braking force. 

Air brakes consist of a compressor, air reservoirs, valves and chambers. These systems carry pressurised air that operates actuators. When the brake pedal is depressed, these actuators push the brake shoes against the rotor or drum, causing the truck to come to a stop. The only challenge is that air brakes are under a constant pressure of between 100-120psi. Maintaining this pressure puts strain on seals and fittings, which can lead to air leaks that reduce braking performance.

Common Causes of Air Leaks on Trucks

Air systems need regular maintenance to prevent leaks and ensure air-powered systems are working as intended. It’s normal for air systems to wear out slowly over time. This may cause your truck to develop air leaks due to:

  • Faulty fittings. Each component of your air system is joined together with fittings. These fittings are typically made of copper, brass or nylon. Even when they’re brand new, fittings can cause air leaks due to incorrect installation or manufacturing errors.
  • Leaking seals. Air brake systems contain a large number of seals, gaskets and o-rings. These seals wear out during normal use and need to be replaced at regular intervals.
  • Corrosion. The underside of your truck can be subject to serious water damage, dirt and road contaminants. While modern brake fittings are designed to be corrosion-resistant, these contaminants cause rust, which eventually leads to air leaks.
  • Wear and tear on hoses. Most modern air brake systems use flexible hoses to connect the compressor, air reservoirs and brakes. These hoses are a cost-effective solution, but they’re prone to chafing, cracking and breaking. These issues can occur during normal use. It’s important to have your air lines regularly inspected for signs that the hoses need to be replaced.

How to Fix an Air Leak on a Truck

Air leaks won’t just slow you down, they can see you laid up for days or weeks while the problem is addressed. A lack of braking isn’t just a roadworthy fail, it’s a serious safety hazard, so it’s important to find and fix air leaks as soon as possible.

Unfortunately, it’s not always that easy. There’s no such thing as a perfectly sealed system. It’s normal for very small amounts of air to leak out of fittings during use. The problem occurs when fittings, hoses and seals begin to break down. These issues all create small leaks that are almost impossible to detect without specialist equipment.

In most cases you will need to take your truck to a qualified mechanic to diagnose and repair an air leak. Your mechanic has access to diagnostic tools such as ultrasonic leak detectors that can identify tiny leaks in minor components. With these specialist tools, a mechanic can examine each part of your braking system, locate the leak and perform the repairs you need. That means you don’t need to spend weeks crawling around under your truck looking for the problem – a mechanic can fix the issue and get you back on the road sooner.

Keep Your Trucks and Machinery in Perfect Condition with KS Mobile Diesel!

Your brakes work hard, all day every day. They not only need the power to stop tonnes of steel, they need to be able to withstand dirt, grime, chemicals and thousands of kilometres on the road. When you have places to be, the Diesel Repair Service team at KS Mobile Diesel can ensure you’ll never be stranded by air leaks!

KS Mobile Diesel is an experienced mobile diesel mechanic that works all over Brisbane and South East Queensland. We specialise in providing maintenance and repairs for all types of vehicles, trucks, machinery and diesel equipment. Our Fleet Maintenance Services technicians carry state of the art diagnostic equipment that’s compatible with all major manufacturers. That allows our Mobile Diesel Service experts to visit your site, diagnose problems and provide repairs that get you back on the road as soon as possible. If you need a mobile diesel mechanic for a truck breakdown service or roadworthy inspections then feel free to contact us and make a booking today!

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