How to Fix an Air Leak on a Truck

Trucks are an essential industry in Australia. They travel millions of kilometres in some of the world’s harshest conditions, and that means air leaks can quickly become a serious problem.

Air leaks reduce braking performance and fuel efficiency, and create a major safety hazard on the road. If you want to avoid being stranded by leaky air brakes, it’s important to invest in regular brake maintenance.

In this article, we learn how to identify and fix air leaks in your braking system, and some of the common causes of these leaks.

How to Find an Air Leak in Your Brake System

Air leaks in your truck’s braking system can cause a partial or total brake failure. The simplest way to locate an external leak (e.g. from a faulty hose fitting) is to use a diluted mixture of soap and water:

  1. 1
    Allow the truck to idle and build up full pressure in the air system
  2. 2
    Turn off the engine
  3. 3
    Mix dish soap and water in a spray bottle
  4. 4
    Working along the length of the truck, listen for the sound of any air leaks
  5. 5
    Spray the soapy water onto tanks, hoses, fittings and valves as you go
  6. 6
    The soapy water will foam up instantly when it comes into contact with an air leak

This is easiest to do when without a load or trailer attached. If you are working in a quiet area, you may be able to hear an air leak, but small leaks will be harder to identify.

But this method is only effective for external air leaks. Air leaks may also occur between faulty valves within the braking system. These issues can be harder to identify, and you’ll need to ask a diesel mechanic to look at the truck.

Get Air Leaks Diagnosed by Kel Stanton’s Mobile Diesel Service

Leaky air brakes can leave you stranded on the side of the road. When you have places to be, Kel Stanton’s Mobile Diesel Service can get you moving again.

Our technicians are experts in air brakes, so we can identify and repair any leaks in the system. Contact us to book an appointment!

How to Fix an Air Leak on a Truck

Leaking air brakes is a roadworthy fail and a serious safety hazard. 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.

How Do Air Brakes Work?

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.

Air brakes offer better performance for heavy vehicles that need significant stopping force. 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 brakes need regular maintenance to prevent leaks and ensure the system functions properly. It’s normal for air systems to degrade due to:

  • Faulty fittings

  • Leaking seals

  • Corrosion

  • Wear and tear on hoses

Each component of your air system is joined 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.


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

Your brakes work hard every day. They need to stop tonnes of steel while withstanding dirt, grime, chemicals and thousands of kilometres on the road.

When you have places to be, the diesel repair service team at Kel Stanton’s Mobile Diesel can ensure you’ll never be stranded by air leaks!

Kel Stanton’s Mobile Diesel Service 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.

If you need a mobile truck mechanic, contact us and make a booking today!


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