glowing brake pads on a race car

Putting The Squeeze On Speed

On of the most critical components in a disc-fitted auto brake system relates to the use and operation of brake calipers. This particular element provides for the central control point between pushing the brake pedal down, and the moment that the brake system activates, thereby slowing or stopping the vehicle. Without this component, no disc brake system works properly or safely.

Within the brake caliper housing several subordinate elements exist including caliper pistons, and inner and outboard brake pads. These sub-components act on the basis of hydraulic principles and ultimately create necessary friction on the brake rotor to slow or stop a car entirely. Consequently, let’s take a deep dive into the design of calipers with an eye toward knowing more than the average driver.

What are brake calipers?

The phrase brake caliper represents a modern derivative of the Latin words plurale tantum, this device was originally known to be used as early as the 6th Century BC to measure distance from a fixed point to a secondary point on a map, or flat-plain architectural feature. In automotive terms, however, today’s automotive phrase is typically applied to a U-shaped clamping mechanism that fits over the top of a brake rotor.

When pedal pressure is applied by the driver, brake fluid is pulled from the brake master cylinder’s storage vessel and is subsequently delivered to the brake caliper through a secondary component called a slave cylinder. In turn, this action extends a series of hydraulic pistons within the caliper housing that drive both inner and outbound brake pads simultaneously.

The piston stroke process applies friction to the brake rotor surface based on the level of pedal intensity. The ultimate goal of the evolution is to retard the rotor’s measured speed, by either slowing or stopping the vehicle entirely, again, depending on the intensity of the driver’s pedal pressure.

Now that you know how a brake caliper works in principle, we’ll take a closer look at what brake calipers mean to an average driver from a more practical perspective.

How complicated is it to ensure that calipers produce even braking?

While today’s overall caliper design involves reasonably simple principles, utilizing these components in practice becomes a bit more complicated than simply ensuring that a set of brake pads drive against a rotor disc on-demand. For example, laying a set of brake pads equally on all four disc’s simultaneously requires a fair amount of engineering, otherwise the car is likely to slew and skew all over the road, sometimes referred to as ‘uneven braking’.

In this event manufacturers ‘build in’ various internal structures to establish baseline piston behaviors that offer dependability on demand. While calipers are largely ‘sealed’ there are other supporting components including oversize rotors, enhanced master/slave cylinder packages, metalized lines to reduce or eliminate line over-pressurization , and other bits that can end up altering the way that calipers behave on the road.

What types of calipers apply to performance auto brake systems?

In general there two principal variants relating to this question. The first design is referred to as a ‘fixed caliper’ configuration, while the second is called a ‘floating caliper’ system. In the former case, the caliper houses pistons that trigger pad contact from both sides to the rotor surface simultaneously, thereby ensuring even friction. In the latter case, only a single-set of pistons push a single set of pads against the rotating surface, while a fixed set of pads support the process from the other side, thereby forming a vise-like construct.

What brake caliper maintenance is necessary?

Yes. Like any other component, brake calipers fail over time. The goal, then, is to ensure that any problems are caught early enough that an even larger problem is avoided. In this case periodic visual inspection should be applied including investigation of any leaks, cracks or abnormalities that may exist.

Do I need to maintain the calipers?

As one might expect, a fully-equipped shop with requisite tools, is typically required to maintain a caliper set. Consequently, it is best to have an experienced mechanic deal with this kind of issue.

What types of brake calipers apply to performance cars?

Most fixed caliper systems apply to consumer cars as a general rule. However, in the case of performance driving, it is best to use floating caliper configurations in order to produce maximum frictional power on demand.