Chevrolet Cobalt Service & Repair Manual: Brake System Bleed
| Brake fluid is corrosive to painted
surfaces. Care must be taken not to allow brake fluid to come in contact
with painted surfaces on vehicle. |
| When bleeding the brake system,
always bleed righthand rear wheel circuit first, followed by the lefthand
front, lefthand rear and, finally, righthand front. |
Manual
| Pressure bleeding is recommended
for all hydraulic systems. However, if a pressure bleeder is unavailable,
use the following procedure. Brake fluid damages painted surfaces. Immediately
clean any spilled fluid. |
| 1. |
Remove vacuum reserve by pumping brakes
several times with engine off. |
| 2. |
Fill master cylinder reservoir with
clean brake fluid. Do not let reservoir fall below half full
during bleeding procedure. |
| 3. |
If required, bleed master cylinder
as follows: |
| |
a. |
Loosen master cylinder forward brake
line connection until fluid flows from reservoir, then tighten brake
line. |
| |
b. |
Have assistant to slowly depress brake
pedal one time and hold. |
| |
c. |
Loosen front brake line connection
and purge air from cylinder. |
| |
d. |
Tighten connection and slowly release
brake pedal. |
| |
e. |
Wait 15 seconds, then repeat previous
steps until all air is purged. |
| |
f. |
Bleed rearward brake line connection
by repeating previous steps. |
| 4. |
Loosen and tighten bleeder valves at
all four wheels. |
| 5. |
Bleed calipers or wheel cylinders in
sequence outlined in "Bleed Sequence." |
| 6. |
Place one end of transparent tube over
bleeder valve and submerge other end into transparent container
filled with clean brake fluid. |
| 7. |
Have assistant slowly depress brake
pedal one time and hold. |
| 8. |
Loosen bleeder valve and purge air
from wheel cylinder or caliper. Tighten bleeder screw and slowly
release pedal. |
| 9. |
Wait 15 seconds and repeat previous
steps until all air is bled from system. |
|
Pressure
| 1. |
Loosen and tighten bleeder valves at
all four wheels. |
| 2. |
Install suitable bleeder adapter to
master cylinder using diaphragm type pressure bleeder. |
| 3. |
Charge bleeder ball to 20-25 psi. |
| 4. |
Connect pressure bleeder line to adapter. |
| 5. |
Open line valve on pressure bleeder
and depress bleed-off valve on adapter until small amount of brake
fluid is released. |
| 6. |
Raise and support vehicle. |
| 7. |
Bleed calipers or wheel cylinders in
sequence as outlined in "Bleed Sequence." |
| 8. |
Place one end of transparent tube over
bleeder valve and submerge other end into transparent container
filled with clean brake fluid. |
| 9. |
Open bleeder valve approximately, 3/4
turn and allow fluid to flow into container until all air is purged
from line. |
|
Bleed Sequence
| On models equipped with front
and rear split system, righthand rear, lefthand rear, righthand front,
lefthand front. If pressure bleeding, bleed front brakes together and rear
brakes together. |
| On models equipped with diagonally
split system,righthand rear, lefthand front, lefthand rear, righthand
front. |
1.
Raise and support vehicle, then remove
tire and wheel assemblies.
2.
Tighten suitable C-clamp until piston
is compressed into ca ...
Replacement
1.
Raise and support vehicle, then remove
tire and wheel assemblies.
2.
Install and tighten two wheel nuts
opposite to ...
Brake Pad Service
Caliper Service