Air brakes vs hydraulic brakes are two different types of braking systems used in vehicular applications. Air brakes use compressed air to slow the vehicle while hydraulic brakes use fluid pressure generated by a pump.
The main difference between them is that air brake parts are exposed to ambient conditions, which can lead to corrosion and freezing.
Though, hydraulic brake parts are inside the wheel cylinder. This means they’re protected from extreme weather conditions.
There’s also a big difference in how they operate. In this article, we’ll explain the complete difference between air brakes vs. hydraulic brakes.
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Hydraulic Brakes Use Brake Fluid
Brake fluid is the main working element of a hydraulic brake system. It’s designed to absorb heat and pressure while transferring it safely through all parts of the braking system.
Hydraulic brakes work with an in-line pump that’s located behind or below your vehicle’s master cylinder (MC).
A typical MC consists of two pistons: one for each wheel assembly, which forces hydraulic fluid into line valves via hoses attached to both ends.
On most modern vehicles, there are four different types of valves controlling separate circuits:
- Front axle circuit
- Rear axle circuit
- Emergency/parking brake valve
- Trailer air supply hose
All these valves help distribute compressed fluid evenly throughout the entire braking system. This is so it can activate the brakes on each wheel.
This way, all four wheels receive pressure at once which allows for even and consistent braking force.
Also, hydraulic brake fluid increases in volume while under intense heat.
So, it’s important that you don’t overfill your reservoirs when adding new fluid to keep air bubbles out of the system.
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Air Brakes Use Air to Operate
Air brakes are the most common type of brake system used on large commercial trucks. The basic components include air tanks, control valves, tubing, and hoses to connect all parts together.
The major elements for an air braking system are compressor (to create pressure), receiver tank (stores compressed air), and dump valve (allows excess compressed air escape).
When you apply your vehicle’s service brakes, a change in cabin pressure is detected by the brake controller assembly located under your dashboard.
This activates electric solenoids blocking or allowing airflow from your main supply line into small rubber tubes attached to each wheel cylinder.
This process forces pressurized air outward against pistons inside cylinders. This activates pads on either side of rotors to create friction and slow the vehicle.
Since air brakes use compressed air, they work even when the engine isn’t running as long as you have a functional electrical system.
However, if your compressor fails, you won’t be able to stop the truck which can be very dangerous.
That’s why it’s important to check your compressor regularly for any leaks or damage with an air brake test.
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Hydraulic Brakes are Used Mostly in Passenger Vehicles
While hydraulic brakes are commonly used in commercial trucks, passenger vehicles use air brake systems.
This is because the volume of fluid required for a larger vehicle would be too much and could cause damage to other components like ABS (anti-lock braking system).
However, some cars do have rear drums that work with hydraulic fluids while others will utilize electric power assistance when using parking brakes.
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Air Brakes Are Designed to Stop Trucks Quickly
When air brakes are applied, a large volume of compressed air is released to slow the vehicle.
Since trucks have heavy loads and high top speeds, they need quick stopping ability. So, it’s important that your truck has great air brake performance.
In most cases, your truck should be ABS-equipped on one or both axles if possible due to its advanced anti-lock technology designed specifically for this type of system.
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Minor Leaks Can Disrupt Air Brakes
A part of your air brake system that should be checked regularly is the rubber tubing.
Even a small hole or crack in this section can cause major problems. This is since it could prevent you from stopping, endangering yourself and other drivers on the road.
So keep an eye out for any leaks around these parts which are very common especially if they’re exposed to high heat or sharp objects like rocks.
Also, remember that air brakes work even when your engine isn’t running so always check under the hood before driving away just in case there’s any damage to the system’s hoses.
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Hydraulic Brakes Work Faster than Air Brakes
While air brakes take a little longer to fully engage, hydraulic brakes provide almost instantaneous stopping power.
This is due to the fact that fluids can transmit pressure faster than compressed air and there’s no need for solenoids or electric systems to activate them.
Though, this also means that your vehicle needs to be in good mechanical condition since an issue could cause you to lose braking ability.
Just like with air brakes, it’s important to check fluid levels regularly and top off when necessary.
Also, make sure all hoses and connectors are free from leaks and damage so you don’t experience any sudden system failures while on the road.
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Air Brakes are More Complex Than Hydraulic Brakes
Since air brakes use more components and a larger system, they’re typically more complex than hydraulic brakes.
This means that there are more things that can go wrong and it takes longer to diagnose and repair problems.
However, with regular maintenance, both types of brakes should last you for years without any major issues.
When it comes to choosing the right braking system for your truck, there are many factors to consider.
Air Brakes vs. Hydraulic Brakes: The Final Verdict
The topic of air brakes vs. hydraulic brakes is a common one. Both brake types are used in passenger cars and light trucks. All in all, air and hydraulic brakes are very strong and durable.
Hydraulic brakes are used in passenger cars we drive every day. Air brakes are used for trucks and larger vehicles. Whether you drive or repair cars, it’s important to know the difference.
To learn more about this subject, continue reading our blog for more helpful articles.
