Hydraulic Brake Line - Chevrolet 10 1971 Series Chassis Service Manual

BRAKES 5-4
Fig. 6— Bleeding Brakes with Tool J—21472
If the main cylinder is equipped with
NOTE:
bleeder valves, bleed these valves first, then
proceed to the wheel cylinder nearest the master
cylinder then, the next nearest and so on until
all cylinders have been bleed and there is no
evidence of air,
4. Pour a sufficient amount of brake fluid into a trans­
parent container to ensure that the end of the bleeder
hose will remain submerged during bleeding. Place
the loose end of the bleeder hose into the container.
Carefully monitor the fluid level at the
NOTE:
main cylinder during bleeding. Do not bleed
enough fluid at one time to drain the reservoir.
Replenish as needed to ensure a sufficient amount
of fluid is in the main cylinder at all times.
5. Open wheel cylinder bleeder valve by turning tool
J-21472 counter-clockwise approximately 1/3 of a
turn. Have helper depress the brake pedal. Just
before the brake pedal reaches the end of its travel,
close the bleeder valve and allow the brake pedal
Fig. 8— Brake Tube Support
to return slowly to the released position.
Step until expelled brake fluid flows in a solid
5
stream without the presence of air bubbles, then
close the bleeder valve tightly.
6. Remove brake bleeder wrench and hose from the
bleeder valve and repeat Steps 2 through 6 on the
remaining wheel cylinders.
7. Fill the main cylinder to the level shown in Figure 7.
8. Install the main cylinder diaphragm and cover.
In order to have a good surge of fluid at
NOTE:
the bleeder valve, the brake pedal should be
pumped up and pressure held before each open­
ing of the valve,
HYDRAULIC BRAKE LINES A N D TUBING
(Figs. 8 and 9)
Hydraulic Brake Hose
These hoses require no service other than periodic
inspection for damage from road hazards or other like
sources. Should damage occur and replacement become
necessary, the following procedure is to be followed.
Removal
1. Put a mark on the frame bracket and flex hose as an
aid when re-assembling.
2. Separate steel line from flex hose.
3. Remove clip retainer from frame bracket and remove
hose.
4. Remove hose to caliper bolt and remove hose.
Installation (Fig. 8)
1. If replacing old hose with a new hose be sure to
transfer the index mark to the new hose in proper
position.
2. Install the hose to the caliper using new gaskets.
Torque the mounting bolt.
3. Install the flex hose to the frame bracket with the
index marks lined up.
The hose should enter the bracket with a
NOTE:
slight twist of about 20° of the hose.
4. Install the clip retainer.
5. Install the steel line to the flex line.
6. Bleed brakes as outlined in this section.
Repeat
10-30 CHEVROLET TRUCK SERVICE MANUAL