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How
Does it Work /
Brake Rotors
How Does a Brake Rotor Work?
Introduction:
A brake rotor is designed to utilize brake pressure provided by the
brake system
to stop the car. This brake rotor utilizes friction and heat to convert momentum
into stopping power. Brake pads ride against either side of the brake rotor and
are held in place by the
brake
caliper. A brake caliper is typically mounted to the spindle or backing
plate. There are two basic designs of brake caliper mounting, fixed and
floating. A fixed position brake caliper is bolted to the spindle and is not
allowed to move. The brake master cylinder supplies the hydraulic pressure to
activate the
brake pads. Brake rotors can either be solid or ventilated (image below)
depending on the application design. Most brake rotors can be re-machined, there
is a minimum thickness measurement requirement designed to uphold performance
specifications. Once a rotor reached this minimum measurement the rotor must be
discarded. A brake rotor is only capable of holding a specific amount of heat,
once this level is reached the brake rotor will not hold additional heat causing
brake fade. Brake fade is a condition that will hinder the brake performance
until the brake rotor has cooled. If a brake rotor is subjected to prolonged
over heat conditions it can destroy the rotor by crystallizing the metal the
rotor is constructed from.
Brake Rotor (appearance will vary)
When brakes pads wear out it will cause the rotor to contact the brake pad
backing plate. This backing plate is made of metal and will destroy the brake
rotor (image below). If this condition is allowed to continue brake operation
could fail completely. When replacing a brake rotor always insist on high
quality replacement brake rotors. If cheap replacement parts are used it can
cause the brake rotor to squeak and prematurely warp due to heat. If you are
replacing
brake pads and not brake rotors a newly machined surface is recommended
before installing new brake pads to ensure proper brake operation. If this
operation is not performed it can cause the brake pedal to pulsate or the brakes
to squeak.
Broken Brake Rotor
Replacing a Brake Rotor:
- Loosen but (Do Not Remove) the lug nuts of the
wheel to be serviced
- Support car in a safe position high enough to remove the brake rotor and
pads
- Remove the lug nuts and wheel
- Use a pry bar to force the caliper piston into the caliper
- Loosen appropriate nuts and bolts to remove the brake caliper
- Remove the caliper, brake pads and rotor
- Clean all rotor and brake pad mounting surfaces
- Install new brake pads and rotors (or re-machined rotors) and reassemble
- Tighten all caliper mount bolts
- Slowly push the brake pedal down and then up to take up air gap space between
the brake pad and rotor
-
Bleed brake system as needed
(note: if the system was never opened it probably does not need to be bled)
- Inspect brake caliper and hose connection for leaks, if brake fluid leaks
exist repair as needed and bleed system
- Reinstall wheel and lug nuts, lower the tire onto the ground and then finish
tightening lug nuts
- NEVER MOVE A CAR WITHOUT NORMAL BRAKE PEDAL OPERATION
Preferred Procedure: When tightening any brake component
including the lug nuts it should be done using a torque wrench to manufactures
specifications. For manufacturer replacement guides, service procedures and
torque specifications consult a
car repair manual.
Common Problems
- When replacing a brake caliper make sure the sealing washer is not leaking
- If a brake caliper slide has seized use an anti-rust solvent such as wd40
or equivalent
How to Remove a Brake Rotor Video
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How to Change Front Brake Pads and Rotors
How Does it Work
/ Brake Rotors
Check Manufacturer Specific Brake
Rotors Question and Answers
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