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Up to 25% Off Online Orders of Select Parts & Accessories. Enter Promo Code MMJ25 in Cart.

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Receive Up To 25% Off Your Online Purchase Of Select Parts and Accessories Instantly

When items are added to the cart, the discount will automatically deduct off the price of the qualifying items. Offers not valid in combination with any other discounts, promotions or items already on sale. Not valid on gift cards, special orders, installation, commercial or fleet purchases. Those products that are included in these offers will be displayed in product search results and product detail pages. Excludes select products, items already on sale and MAP priced brands & items. For full category inclusions and disclaimers, See Details Here. Valid online until 11:59 PM EST on 6/30/18.

Additional Promotions Not Included in the above:

Receive 20% Off Select Wagner branded brake parts with your online purchase.

Receive 10% Off Select Champion branded products with your online purchase. Use promotional code: CHAMP10.

Receive 10% Off Select FelPro branded products with your online purchase. Use promotional code: FELPRO10.



Brake calipers are essential to helping your vehicle stop safely. Brake calipers are hydraulic actuators that transfer force from application of the brake pedal to the friction material (brake pads) via hydraulic fluid contained in lines that interconnect the brake pedal assembly and the calipers. Calipers may be used on the front or rear brakes and are mounted to the spindle assembly over the brake rotors.



What is a Brake Caliper?

Brake calipers are part of your vehicle’s braking system. Their purpose is to hold the brake pads. There are two main types of calipers: floating calipers that move in and out relative to the rotor and have one or two pistons only on the inboard side of the rotor, and fixed calipers that don’t move but have pistons arranged on opposing sides of the rotor.

How do Brake Calipers Work?

The transfer of energy begins with operation of the brake pedal, which transfers motion to the brake master cylinder. Pedal motion causes a piston in the master cylinder to push hydraulic fluid out into the brake lines. The pressurized fluid is directed to the calipers and/or wheel cylinders at all four road wheels. Pressurized brake fluid enters the caliper, filling the chamber behind the caliper piston and forcing the piston outward. As pressurized brake fluid forces the caliper piston outward, it pushes the friction material into contact with the brake rotor. The caliper applies braking pressure to the friction material proportionate to the applied force from the vehicle operator. Upon completion of the braking action, the brake pedal is released, brake fluid pressure reduces and the caliper piston and friction material are retracted away from the brake disk.

How are Brake Calipers Made?

The caliper is traditionally cast of a lightweight aluminum material. Older brake caliper designs may be cast iron. The brake caliper can operate using 1, 2, 4, or even 6 pistons. Single piston designs are designed to allow the caliper to center during application so that the inboard friction material has an equally applied force with that of the piston side. Dual, 4 or 6 piston calipers apply hydraulic force from both sides of the caliper. Many calipers float (center) on the rotor via caliper guide pins, components that affix the caliper to the caliper bracket assembly. Calipers incorporate an integral “bleeder” screw, wherein any entrapped air can be removed, should the caliper or related hoses be removed or replaced.

Why do Brake Calipers Fail?

  • Brake calipers most often fail when internal rust and corrosion cause the hydraulic piston to seize in the bore. This occurrence is easily avoided by periodically replacing your brake fluid
  • Seized caliper guide pins are another frequent cause of caliper failure. If these pins seize in the caliper bracket bore, the bracket normally needs to be replaced. Use of a quality caliper grease can help to avoid this issue
  • Broken bleeder screws are another frequent cause of caliper failure. These small hollow screws will sometimes bind in the caliper housing and break off when attempting to bleed air from the system

What are Symptoms of Brake Caliper Failure?

  • Asymmetric brake pad wear, where either the inner or outer pad is worn more than the other, usually indicates binding caliper guide pins.
  • Dissimilar pad wear on either the passenger or driver side often indicates that the side with less wear either has air trapped in that side of the brake hydraulics or the affected caliper has a seized piston. Steering pull under braking often accompanies this visual symptom.
  • Brake pads soaked with dark colored fluid and an accompanying odor often indicate a leaking brake caliper, where fluid has contaminated the friction material. A leaking caliper is unsafe and should be replaced at once.

What are Implications of ABS Brakes Failure?

  • Brakes are a critical safety system of any vehicle. A leaking, seized, or binding brake caliper will reduce braking effectiveness and increase stopping distance. Any brake caliper that is suspect should be replaced.

If you have questions or concerns about your anti-lock braking system, or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.

If you want to learn more about other car parts, especially as they apply to anti-lock brake systems, we recommend reading up on brake rotors, brake lines and steering gear boxes