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Section 2
Hydraulic Brakes
2. Loosen the bleeder screw and slowly push the
brake pedal to the floor. Close the bleeder
screw before you release the brakes. If the
bleeder hose is kept submerged in the
container of brake fluid, it is not necessary to
close the bleeder screw on each application.
Repeat this procedure eight or ten times on
each component bleed.
3. Fill the master cylinder or power cluster with
the correct hydraulic fluid and check the brake
pedal for correct pressure and travel. (The
brakes must be in correct adjustment).
a. If pressure bleeding equipment is used,
connect the outlet hose to the master
cylinder or power cluster and bleed the
system following the same procedures as
above. The flow of the brake fluid must be
checked while the bleeder hose is kept
submerged in the brake fluid in the
container. When the air bubbles are
eliminated and the brake fluid runs in a
clean, solid flow, the bleeding is complete.
b. If vacuum bleeding equipment is used,
small air bubbles can be drawn past the
cylinder seals into the wheel cylinders. A
conventional bleed of each wheel
cylinders. A conventional bleed of each
wheel cylinder should be performed after a
vacuum bleeding.
4. Repeat this procedure at each wheel cylinder.
Fill the master cylinder reservoir after each
wheel cylinder is bled.
5. When bleeding is complete, check the fluid
level of the master cylinder. If necessary, fill to
the specified level.
Assemble Wheel Cylinder
1. Before the cylinder is assembled, lubricate the
new cups and the piston with the correct
brake fluid.
2. If the boots are deteriorated, or do not fit
tightly on the push rods and the cylinder
housing, replace the boots.
3. Wash the wheel cylinder with brake fluid.
4. Install the spring in the cylinder.
5. Install the cups in each end of the cylinder with
the open ends of the cups toward each other.
6. Install the pistons in each end of the cylinder
with the recessed end of the pistons toward
the open ends of the cylinder.
7. |Install dry boots over each end of the cylinder.
Bleed Hydraulic System
After servicing the brakes it is necessary to bleed
all of the components of the hydraulic system.
Follow the bleeding instructions in the OEM’S
vehicle maintenance manual. If the manual is not
available, the following procedures will provide a
proper bleed:
Bleeding must start first with the hydrovac,
power cluster or master cylinder. The first wheel
cylinder to be bled MUST be the one that is the
greatest distance from the master cylinder.
CAUTION
Some hydraulic brake systems use a non-
petroleum hydraulic brake fluid (SAE-J-1703 or
SAE-J-1702f) some hydraulic brake systems use
petroleum base brake fluids. Make sure that you
use the correct brake fluid and seals as required
in the vehicle brake system specifications. The
use of the wrong brake fluid can damage the cup
seals of the wheel cylinder. Different types of
brake fluids MUST NOT be mixed.
1. Fill the master cylinder with brake fluid.
Connect one end of the bleeder hose to the
bleeder screw and hang the other end of the
hose in a clean container. Do not permit fluid
to contact brake lining.
