In the 1990s, anti-lock brakes (ABS) were the new standard for vehicle manufacturers. If you have never owned a vehicle that was manufactured before then, you may not realize that there was once a different kind of brake system (power brakes) used. What is the difference between the two? Let’s break it down.
A couple of things happen when you hit the brakes, regardless of the type. The pedal strut is attached to a rod that enters the master cylinder. In an ABS vehicle, the master cylinder is connected to the firewall. For power brake vehicles, it is first connected to a vacuum booster, which is then connected to the firewall. This rod activates the pistons that are in the master cylinder which pushes brake fluid into the lines. This brake fluid starts a piston at the brake caliper that pushes the brake pads against the rotor, slowing your vehicle with friction.
Power brakes were created during World War II to make heavy war vehicles easier to slow and stop. They were once offered as an option when purchasing a vehicle but became standard after the 1960s.
Vacuum Power Brakes. We mentioned above that power brake systems have a vacuum booster component. When an engine runs it creates a good bit of vacuum. Power brakes transmit some of the engines vacua to a power-brake booster for storage. The stored vacuum multiplies the pressure your foot puts on the pedal which makes braking easier on you and shortens your stopping distance.
Hydroboost Power Brakes. Other power brake systems have something called hydroboost. Hydroboost distributes power-steering fluid to a booster pressurized by the power-steering pump. This form of power brake creates even more pressure for braking than the vacuum boost. Hydroboost power brakes are ideal for diesel engines because they generate less natural vacuum. This design takes less space and is a better fit for vans and other vehicles with a cramped engine compartment.
Anti-Lock Brakes (ABS)
The anti-lock braking systems were first concocted in the 1950s for aircraft and not regular driving vehicles. Like power brakes before them, ABS was once an option but is now the standard on new vehicles.
Anti-lock systems have sensors that track the rotational speed of your wheels and send real-time information to a processor. The processor sends signals to a series of pumps and valves that portions the braking force applied to each wheel.
If a wheel seems like it may lock up and skid or one wheel appears to slow more than the others, the processor will reduce the pressure in the brake line to that specific wheel. This function is important because, in hard stop situations, a locked wheel can be very dangerous.
As the new braking system standard, your 1990s or newer vehicle will have an ABS dashboard light. If this light comes on, your vehicle may have a problem with a sensor or computer trouble code. Rarely is it something more serious than this as ABS systems are tough and typically last for the life of your vehicle.