Chevrolet Trax: Hydraulic brake system bleeding (pressure)
WARNING: Refer to Brake Fluid Irritant Warning .
CAUTION: Refer to Brake Fluid Effects on Paint and Electrical
Components Caution .
CAUTION: Only use products that comply with GM specifications and check
manufacturer information respectively. We recommend the use of GM
genuine products. Instructions must be followed at all times. The use of
any type of fluid other than the recommended type of brake fluid, may
cause contamination which could result in damage to the internal rubber
seals and/or rubber linings of hydraulic brake system components.
If hydraulic components were serviced on only one wheel hydraulic circuit,
perform the following procedure
Bleeding a Single Hydraulic Brake Circuit
- With the ignition OFF and the brakes cool, apply the brakes 3-5 times,
or until the brake pedal effort
increases significantly, in order to deplete the brake booster power
reserve.
- Place a clean shop cloth beneath the brake master cylinder to catch
brake fluid spills.
- Clean the outside of the reservoir on and around the reservoir cap prior
to removing the cap and
diaphragm.
- Fill the brake master cylinder reservoir to the maximum-full level with
GM approved brake fluid from a
clean, sealed brake fluid container. Refer to Fluid and Lubricant
Recommendations
NOTE: The pressure bleeding equipment must be the diaphragm type.
The rubber
diaphragm between the air supply and the brake fluid prevents air,
moisture, oil, and other contaminants from entering the hydraulic system.
- Following the brake pressure bleeder manufacturer's instructions, fill
the brake pressure bleeder with GM
approved brake fluid from a clean, sealed brake fluid container.
- Install the appropriate master cylinder reservoir adapter and connect
the brake pressure bleeder.
- Charge the brake pressure bleeder air tank to 170-200 kPa/1.7-2.0 bar
(25-30 psi), or as recommended by
the brake pressure bleeder manufacturer's instructions.
- Open the brake pressure bleeder fluid tank valve to allow pressurized
brake fluid to enter the brake
hydraulic system.
NOTE: Any brake fluid leaks identified require repair prior to
completing this
procedure.
- Wait approximately 30 seconds, then inspect the entire hydraulic brake
system for external brake fluid
leaks.
- Install a proper box-end wrench onto the wheel hydraulic circuit bleeder
valve which has been serviced.
- Install a transparent hose over the end of the bleeder valve.
- Submerge the open end of the transparent hose into a transparent
container partially filled with brake fluid
from a clean, sealed brake fluid container.
- Loosen the bleeder valve to purge air from the wheel hydraulic circuit.
- Allow fluid to flow until air bubbles stop flowing from the bleeder.
- After all air has been purged from the hydraulic circuit, tighten the
bleeder valve and install the dust cap.
NOTE: The brake reservoir may have residual pressure after the
bleeding
operation is complete. Wrap a clean shop towel around the bleeder
adapter and all hose connections before disconnecting the pressure
bleeding equipment to prevent brake fluid from contacting and damaging
vehicle components and painted surfaces.
- Close the brake pressure bleeder fluid tank valve then disconnect the
brake pressure bleeder from the
master cylinder reservoir bleeder adapter.
- Remove the master cylinder reservoir bleeder adapter from the master
cylinder reservoir.
- Fill the brake master cylinder reservoir to the maximum-fill level with
GM approved brake fluid from a
clean, sealed brake fluid container.
- Slowly press and release the brake pedal. Observe the brake pedal feel.
- If the brake pedal feels spongy, perform the Bleeding the Complete Brake
Hydraulic System procedure:
- Turn the ignition key ON, with the engine OFF. Check to see if the brake
system warning lamp remains
illuminated.
NOTE: DO NOT allow the vehicle to be driven until it is diagnosed
and repaired.
- If the brake system warning lamp remains illuminated, refer to
Diagnostic Starting Point - Vehicle .
Bleeding the Complete Brake Hydraulic System
- With the ignition OFF and the brakes cool, apply the brakes 3-5 times,
or until the brake pedal effort
increases significantly, in order to deplete the brake booster power reserve.
- Place a clean shop cloth beneath the brake master cylinder to catch
brake fluid spills.
- Clean the outside of the reservoir on and around the reservoir cap prior
to removing the cap and diaphragm.
- Fill the brake master cylinder reservoir to the
maximum-full level with GM approved brake fluid from a
clean, sealed brake fluid container. Refer to Fluid and Lubricant
Recommendations .
- If the master cylinder was replaced, the master
cylinder must be bench bled. Refer to Master Cylinder
Bench Bleeding.
- If the brake pipes have been removed from the master
cylinder, the following steps must be performed.
- With the rear brake pipe installed securely to the master cylinder,
loosen and separate the front
brake pipe fitting from the front port of the brake master cylinder.
- Allow a small amount of brake fluid to gravity bleed from the open port
of the master cylinder.
Capture and properly dispose of the brake fluid in an approved container.
- Install the front brake pipe fitting to the front port of the brake
master cylinder and tighten the
fitting.
- Have an assistant slowly press the brake pedal fully and maintain steady
pressure on the pedal.
- Loosen the front brake pipe fitting from the front port of the brake
master cylinder to purge air from
the master cylinder port.
- Tighten the front brake pipe fitting, then have the assistant slowly
release the brake pedal.
- Wait 15 seconds, then repeat steps 6.4-6.6 until all air is purged from
the front brake pipe fitting of
the front port of the master cylinder.
- After all air is purged from the front port of the brake master cylinder,
tighten the front master
cylinder brake pipe fitting. Refer to Fastener Tightening Specifications.
- With the front brake pipe fitting installed securely to the front port
of the brake master cylinder,
loosen and separate the rear brake pipe fitting from the rear port of the
brake master cylinder.
- Repeat steps 6.2-6.7 for the rear port of the brake master cylinder.
- After all air is purged from the rear port of the brake master
cylinder, tighten the rear master
cylinder brake pipe fitting. Refer to Fastener Tightening Specifications.
- Slowly press and release the brake pedal. Observe the brake pedal feel.
- If the brake pedal feels spongy, proceed to step 7.
- If the brake pedal feels firm, proceed to step 24.
- If the brake pipes have been removed from the brake pressure modulator
valve (BPMV) assembly, if
equipped, or the brake proportion valve assembly, if equipped, air must be
purged from each port of the
respective assembly beginning with the feed pipes from the master cylinder.
- Loosen and separate one of the master cylinder brake pipe fittings from
the inlet port of the
assembly to be bled.
- Allow a small amount of brake fluid to gravity bleed from the open port
of the assembly. Capture
and properly dispose of the brake fluid in an approved container.
- Install the brake pipe fitting and to the inlet port of the assembly and
tighten securely.
- Have an assistant slowly press the brake pedal fully and maintain steady
pressure on the pedal.
- Loosen the same brake pipe fitting to purge air from the open port of
the assembly.
- Tighten the brake pipe fitting, then have the assistant slowly release
the brake pedal.
- Wait 15 seconds, then repeat steps 7.4-7.6 until all air is purged from
the brake pipe fitting of the
assembly.
- Repeat steps 7.1-7.7 for all of the remaining ports of the assembly.
- After bleeding each port of the assembly, tighten all of the brake pipe
fittings on the assembly.
Refer to Fastener Tightening Specifications.
- Fill the master cylinder reservoir to the maximum-full level with GM
approved brake fluid from a
clean, sealed brake fluid container.
- Slowly press and release the brake pedal. Observe the brake pedal feel.
- If the brake pedal feels spongy, proceed to step 8.
- If the brake pedal feels firm, proceed to step 24.
NOTE: The pressure bleeding equipment must be the diaphragm
type. The rubber
diaphragm between the air supply and the brake fluid prevents air,
moisture, oil, and other contaminants from entering the hydraulic system.
- Following the brake pressure bleeder manufacturer's instructions, fill
the brake pressure bleeder with GM
approved brake fluid from a clean, sealed brake fluid container.
- Install the appropriate master cylinder reservoir adapter and
connect the brake pressure bleeder.
- Charge the brake pressure bleeder air tank to 170-200 kPa/1.7-2.0 bar
(25-30 psi), or as recommended by
the brake pressure bleeder manufacturer's instructions.
- Open the brake pressure bleeder fluid tank valve to allow pressurized
brake fluid to enter the brake
hydraulic system.
NOTE: Any brake fluid leaks identified require repair prior to
completing this
procedure.
- Wait approximately 30 seconds, then inspect the entire hydraulic brake
system for external brake fluid
leaks.
- Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic
circuit bleeder valve.
- Install a transparent hose over the end of the bleeder valve.
- Submerge the open end of the transparent hose into a transparent
container partially filled with GM
approved brake fluid from a clean, sealed brake fluid container.
- Have an assistant slowly press the brake pedal fully and maintain steady
pressure on the brake pedal.
- Loosen the bleeder valve to purge air from the wheel hydraulic circuit.
- Tighten the bleeder valve, then have the assistant slowly release the
brake pedal.
- Wait 15 seconds, then repeat steps 11-13 until all air is purged from
the wheel hydraulic circuit.
- Tighten the RIGHT REAR hydraulic wheel circuit bleeder valve securely.
- Install a proper box-end wrench onto the LEFT REAR wheel hydraulic
circuit bleeder valve, then repeat
steps 9-14.
- Install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic
circuit bleeder valve, then
repeat steps 9-14.
- Install a proper box-end wrench onto the LEFT FRONT wheel hydraulic
circuit bleeder valve, then repeat
steps 9-14.
- After completing the final wheel hydraulic circuit bleeding procedure,
tighten all of the wheel hydraulic
circuit bleeder valves and install the bleeder valve dust caps.
- Close the brake pressure bleeder fluid tank valve.
NOTE: The brake reservoir may have residual pressure after the
bleeding
operation is complete. Wrap a clean shop towel around the bleeder
adapter and all hose connections before disconnecting the pressure
bleeding equipment to prevent brake fluid from contacting and damaging
vehicle components and painted surfaces.
- Remove the brake pressure bleeding equipment from the vehicle.
- Fill the brake master cylinder reservoir to the maximum-full level
with GM approved brake fluid from a
clean, sealed brake fluid container. Refer to Fluid and Lubricant
Recommendations .
- Slowly press and release the brake pedal. Observe the brake pedal feel.
- If the brake pedal feels spongy, perform the following procedure.
- If equipped with antilock brakes, install a scan tool and perform the
Antilock Brake System
Automated Bleed to remove air which may be trapped in the BPMV.
- Inspect the hydraulic brake system for external leaks. Refer to Brake
System External Leak
Inspection.
- Repeat the Bleeding the Complete Brake Hydraulic System procedure.
- If the brake pedal still feels spongy, pressure bleed the hydraulic
brake system. Refer to Hydraulic Brake
System Bleeding (Manual), Hydraulic Brake System Bleeding (Pressure) .
- Turn the ignition switch ON with the engine OFF. Check to see if the
brake system warning lamp remains
illuminated.
NOTE: DO NOT allow the vehicle to be driven until the brake system
is diagnosed
and repaired.
- If the brake system warning lamp remains illuminated, refer to
Diagnostic Starting Point - Vehicle .
READ NEXT:
WARNING: Refer to Brake Fluid Irritant Warning .
CAUTION: Refer to Brake Fluid Effects on Paint and Electrical
Components Caution .
Inspect the brake fluid for the following conditions, indicating
Removal Procedure
With the engine OFF, apply and release the brake pedal several times
until the pedal becomes firm to
deplete the power vacuum brake booster vacuum reserve.
Remove the battery t
Removal Procedure
With the engine OFF, apply and release the brake pedal several times to
deplete the power vacuum brake
booster vacuum reserve.
Raise and support the vehicle. Refer to Lifting a
SEE MORE:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
Diagnostic Fault
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
D