Automotive Disc Brakes Harlem Automotive Technology

Disc Brakes Disc brakes are fairly simple to work with, once you know the parts and their functions. Typically, there are 4 main parts of a system: Mounting Bracket Rotor Caliper Pads Disc brakes are fairly simple to work with, once you know the parts and their functions. Typically, there are 4 main parts of a system: Mounting Bracket Rotor Caliper Pads

Mounting Brackets Mounting Brackets are used to hold the Caliper in place. Other than keeping the surface clean and free of rust and road grime, there is very little to be done with this part

Rotors Rotors are metal discs supported by the suspension. The Calipers clamp on to them to slow their rotation, and then slow or stop the car

Vented Rotor These are the VENTS

Vented Rotors Vented Rotors have Fins in the spaces between their machined surfaces. These spaces allow air to pass through, which helps carry heat away.

Nonvented Rotor Non Vented Rotors are used on smaller vehicles, and have no cooling fins

Non Vented Rotor

Rotor Repair We will get back to these Rotors later concerning what you can do as a repair on them.

Calipers Calipers are the housings that contain the Pistons and the Brake Pads. The Calipers are connected to the Hydraulic System, and hold the brake pads to the Rotor

Caliper Types There are 2 types of Calipers Fixed Floating There are 2 types of Calipers Fixed Floating

Fixed Caliper Fixed Calipers are disc brakes that use a caliper that is FIXED in position and does not slide. They have pistons on both sides of the disc. There may be 2 or 4 pistons per caliper

Fixed Caliper Motorcycles and some import trucks and cars use this type

Sliding Caliper Much more common Single Piston Easier to work with On “inboard” side of caliper Much more common Single Piston Easier to work with On “inboard” side of caliper

Clean, Floating Caliper

Floating Calipers

Operation Piston applies pressure to Inboard pad. As the pad contacts the rotor, the caliper slides along the pins, pulling the outboard pad into contact. Caliper Rotor Piston Brake Pads Brake Line

Sliding caliper in operation

Parts of a Caliper

Seal The rebuild kit will have a new O ring, and a Dust Seal

Piston The Piston surface should be smooth and clean. This one is pitted, and needs replaced.

Adjustments? Disc Brakes will automatically self-adjust. As the Pads wear, the caliper piston will not retract as far This leaves a larger amount of brake fluid in the caliper, causing the master cylinder level to lower

Caliper Slides Notice where the brake pads and calipers slide on the pin and the mount

Caliper slides Since parts need to slide, these areas should be clean of dirt and rust,

Cleaning Caliper With the caliper off, I would use a wire brush to clean the rust off, then use a brake cleaning solvent to wash the sliding area.

Wear Indicators Brake pads wear, and most people never check them. So, something was put on the pads to make a noise, since most people will have a noise checked out.

Just a couple more things…

Diagnosis Several different types of Complaints Noise Pulsation Pedal travel More later…

Brake Noise Wear Indicator

Brake Pulsation Usually a warped Rotor Rotor needs trued on a brake lathe

Pedal Travel NO BRAKES!!!!

Finis Laters Techs…….. Chuck McCrearyHarlem High School