Professional Automotive Experts Answering Your Questions
How
Does it Work /
Brake Caliper
How Does a Brake Caliper Work?
Introduction:
A brake caliper is designed to utilize brake fluid under pressure to transfer
force the brake pads. In-turn the brake pads contact the rotating brake rotor to
slow the car. 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. This kind of brake caliper is constructed with caliper pistons
on both sides of the caliper. The floating style of caliper is mounted to the
spindle or backing plate using a slide bolt. This slide bolt design allows the
caliper to slide on these bolts. This design uses pistons on just one side of
the brake caliper.
Fixed Mount Brake Caliper
Brake calipers can have from 1 to 6 pistons depending on manufacturer design.
All brake calipers are fitted with a brake fluid bleeder. This bleeder is
designed to allow air to escape from the system. If air is allowed in the system
it can cause brake operation failure. A brake caliper piston is sealed to the
brake caliper housing using a main piston seal. This seal allows the piston to
move back and forth without allowing brake fluid to leak. This seal is protected
by a dust seal that keeps debris from contaminating the integrity of the seal.
The brake system should always be flushed and bled regularly to prevent moisture
from creating rust. This rust can cause the caliper piston seal to fail allowing
brake fluid to leak. If your brake caliper is leaking you must replace the
caliper or rebuild the caliper using a brake caliper rebuild kit.
Floating Brake Caliper
This kit replaces the main seal and dust guard. A high pressure brake hose is
connected from the car frame or body to the caliper. This hose is sealed against the
brake caliper using a copper sealing washer. When removing this hose it is recommended
that a new copper sealing washer is installed. Anytime the brake system is opened
a brake system bleed is necessary.
Exploded Brake Caliper (Floating)
Replacing a Brake Caliper:
- 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 caliper
- Remove the lug nuts and wheel
- Loosen the hydraulic brake hose at the caliper, do not remove
- Loosen appropriate nuts and bolts to remove the caliper
- Continue the remove the hydraulic brake hose
- Clean all caliper slides and mounting surfaces, lubricate as needed
- Reconnect hydraulic brake hose
- Re-Install new or rebuilt brake caliper
- Tighten all mounting bolts with the brake hose fitting
-
Bleed brake system as needed
- Slowly push the brake pedal down and then up to take up air gap space between
the brake pad and rotor
- Inspect brake caliper and hose connection for leaks, if brake fluid leaks
exist repair as needed
- 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
Rebuilding a Brake Caliper:
- Once the brake caliper has been removed the caliper piston will need to
be removed this can be done either with a pry bar on either side to work the
piston out of the housing or inserting compressed air into the hydraulic hose
fitting. If compressed air is used use caution because the piston will shoot
out the caliper housing with force. Install shop towels in between the piston
and caliper housing and keep fingers away from the piston.
- When the brake caliper is apart clean all debris and rust from all components.
If severe rust exists replacement is required
- Install new seal with a touch of brake fluid for lubricant and insert the
brake caliper piston into the main caliper housing
- Now install the new dust boot over the piston and into the main housing
- Reinstall caliper to bleed and recheck as needed
- Slowly push the brake pedal down and then up to take up air gap space between
the brake pad and rotor
- Inspect brake caliper and hose connection for leaks, if brake fluid leaks
exist repair as needed
- Reinstall wheel and lug nuts, lower the tire onto the ground then finish
tightening lug nuts
- NEVER MOVE A CAR WITHOUT NORMAL BRAKE PEDAL OPERATION
For manufacturer replacement or service procedures 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 Caliper Video
Get the
Free Flash Player to see this video.
How to Change Front Brake Pads and Rotors
How Does it Work
/ Brake
Caliper
Check Manufacturer Specific Brake
Caliper Question and Answers
Related Subjects
ASK CAR REPAIR QUESTIONS
- Join our question and answer forum where over 10,000 free auto repair
questions are answered every month, after you have completed our free signup
you will able to ask a question and receive an answer from one of our many forum
members. If you elect to donate any small amount of money we will assign one
of our 2CarPros Certified Repair Technicians to answer your question. Questions
with donations are answered promptly and 100% of the donation is awarded to
the technician helping you.
GET ONLINE
CAR REPAIR
MANUALS - Get instant access to your vehicles wiring diagrams, firing
orders, component locator, vacuum diagrams, repair procedures, specific testing
and diagnostics for troubleshooting, steering and suspension information, heating
and air-conditioning problems, safety belt and airbag restraint repair, factory
bulletins and general information and much more. We recommend that anyone needing
technical repair information should have a quality auto repair manual for their
car.
| 
