This document discusses the main components of automotive disc brakes, including the mounting bracket, rotor, caliper, and pads. It describes the purpose and basic operation of each part. The rotor comes in vented and non-vented varieties and can require repair work like truing. Calipers are either fixed or floating and contain pistons and seals. Disc brakes are self-adjusting, and wear indicators help detect when pads need replacement. Common brake issues like noise, pulsation, and excessive pedal travel are also briefly mentioned.

1. Automotive Disc Brakes

2. 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

3. 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

4. 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

5. Vented Rotor
These are
the VENTS

6. 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.

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

8. Non Vented Rotor

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

10. 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

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

12. 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

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

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

15. Clean, Floating Caliper

16. Floating Calipers

17. 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

18. Sliding caliper in operation

19. Parts of a Caliper

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

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

22. 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

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

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

25. 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.

26. 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.

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

28. Brake Noise
Wear
Indicator

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