Description: The brake hydraulic
system consists of the master cylinder, disc brake calipers (disc
brakes), wheel cylinders (drum brakes), hydraulic lines and hoses,
and combination/proportioning valve. When you push on the brake
pedal, the force of your leg generates hydraulic pressure in the
master cylinder, which then flows through the hydraulic lines and
hoses to the wheel cylinders and calipers. The hydraulic force
applies pressure through the wheel cylinders and calipers, forcing
the shoes against the drums (drum brakes) and the pads against the
rotors (disc brakes). In the early 1960's, cars began using split
hydraulic systems and tandem master cylinders. Essentially, this
divided the hydraulic system into two separate systems (front and
back), ensuring proper hydraulic and braking on one side of the
system, if a leak developed on the other side. In the
1980's, some carmakers began to use diagonally split systems, which took
safety a step further. Instead of
splitting the system into front and rear,
the system was now hydraulically divided into left-rear/right-front
and right-rear/left-front. By maintaining
one front and one rear brake, the result is more balanced braking
when the system develops a leak. By
law, all of today's
cars are required to use some type of
hydraulically split system.
Purpose:
The
hydraulic system transmits and
multiples force as
needed to provide braking action throughout the brake
system.
Maintenance Tips/Suggestions: Check the brake fluid level in the master
cylinder reservoir regularly, ideally at every oil change. Most cars
use semi-transparent reservoirs that have level markings to make
fluid monitoring easy. If you need to add fluid, use only the type
of fluid recommended in your car's owner's manual. Do not leave the
cover off the master cylinder any longer than necessary; DOT 3 and
DOT 4 brake fluids attract water. Use extreme care when handling DOT
3 and DOT 4 fluid as it quickly destroys paint if spilled. On cars
with disc brakes, it's normal for the fluid level to gradually drop
as the brakes wear. This fluid fills up the space left by the disc
brake caliper pistons as they move outward with brake wear. However,
if you find that brake fluid needs to be added frequently, there may
be a leak in the
hydraulic system. Have the system inspected as soon
as possible by a qualified service technician. Your owner's manual
may specify
periodic
flushing and filling of the brake hydraulic system, which should not be
overlooked. This is a service best left to professional technicians,
as many cars with ABS have specialized
brake-bleeding procedures. Braking systems with ABS can also generate extremely
high hydraulic pressures, which can be dangerous.
Once again, consult a professional service technician if your car
needs ABS or hydraulic system service. Click here to see a detailed diagram of the brake system.
