Chevrolet Trax: Brake pedal travel measurement and inspection
Special Tools
CH-28662 Brake Pedal Effort Gauge
For equivalent regional tools, refer to Special Tools.
- With the ignition OFF and the brakes cool, apply the brakes 3-5 times,
or until the brake pedal becomes
firm, in order to deplete the brake booster power reserve.
Fig. 3: Steering Wheel, Brake Pedal And Gauge
- Install the CH-28662 gauge (1), or equivalent, to the brake pedal (3).
- Measure and record the distance (a) from the brake pedal (3) to the rim
of the steering wheel (2). Note the
points of measurement.
Fig. 4: Brake Pedal Components And Travel Measurement
- Apply and maintain a force of 445 N (100 lb) to the brake pedal, as
indicated on the CH-28662 gauge (1),
or equivalent.
- While maintaining 445 N (100 lb) of force to the brake pedal (3),
measure and record the distance (b)
from the same point on the brake pedal (3) to the same point on the rim of
the steering wheel (2).
- Release the brake pedal (3) and repeat steps 4 and 5 to obtain a second
measurement. After obtaining a
second measurement, proceed to step 7.
- Average the first and second measurements recorded for the 2 applies of
the brakes.
- Subtract the initial unapplied distance (a), from the average applied
distance (b) to obtain the brake pedal
travel measurement (c).
Specification
Maximum brake pedal travel - measured with the ignition OFF, brake booster
power assist depleted, and the brakes cool.
BRAKE SYSTEM VACUUM SOURCE TEST
NOTE:
- Engine temperature, accessory load, and elevation level will affect
engine
vacuum.
- Vacuum readings will decrease by approximately 2.7 kPa (0.8 in Hg)
for
every 305 m (1000 ft) of elevation above sea level.
- Disconnect the engine vacuum hose from the vacuum brake booster check
valve.
- Install a vacuum gauge to the engine vacuum hose.
- Install a scan tool to the vehicle.
- Start the engine and allow the engine to idle until normal operating
temperatures are reached.
NOTE: To obtain the gauge pressure from the manifold absolute
pressure (MAP)
sensor, subtract the absolute pressure of the MAP sensor from
atmospheric pressure.
- With the vehicle in PARK or NEUTRAL with the park brake on, the engine
idling, and the air
conditioning (A/C) system OFF, check to see if the engine vacuum reading is
the gauge pressure
calculated from the pressure of the MAP sensor indicated on the scan tool.
- Turn the ignition OFF.
- If the engine vacuum reading is within the specified normal range,
proceed to step 11.
- If the engine vacuum reading is NOT within the specified normal range,
inspect the engine vacuum hose
for the following conditions.
- Loose connection to the engine
- Collapse, deformation or contamination
- Cracks, cuts, or brittleness
- If any of these conditions were found with the engine vacuum hose,
replace the hose, then repeat steps 2-
5.
- If none of these conditions were found with the engine vacuum hose, then
there is an engine vacuum
source problem, check the engine vacuum system.
- Remove the vacuum brake booster check valve from the booster.
- Install the check valve to the engine vacuum hose.
- Install the vacuum gauge to the check valve.
- Start the engine and allow the engine to idle in park or neutral with
the park brake on and with the A/C
system OFF, until normal operating temperatures are reached.
- Turn the ignition OFF.
NOTE: To obtain
the gauge pressure from the manifold absolute pressure (MAP)
sensor, subtract the absolute pressure of the MAP sensor from atmospheric
pressure.
- Visually inspect the engine vacuum reading is maintained at the same
gauge pressure as the pressure
obtained form the MAP sensor as indicated on the scan tool.
- If the engine vacuum reading is maintained within the specified
normal range, proceed to step 19.
- If the engine vacuum reading is NOT maintained within the specified
normal range, replace the vacuum
brake booster check valve, then repeat steps 12-16.
- Inspect the vacuum brake booster check valve grommet for the following
conditions:
- Loose connection to the vacuum brake booster
- Deformation or contamination
- Cracks, cuts or brittlene
- If any of these conditions were found with the check valve grommet,
replace the grommet.
READ NEXT:
WARNING: Refer to Brake Fluid Irritant Warning .
CAUTION: Refer to Brake Fluid Effects on Paint and Electrical
Components Caution
In order to inspect for external brake fluid leaks, first inspect t
Disc Brake
Fig. 6: Hydraulic Brake Component Operation
With the tire and wheel assemblies removed and the brake rotors retained
by wheel lug nuts, visually
inspect the brake caliper piston dust
SEE MORE:
DRIVE BELT REPLACEMENT
Special Tools
EN-48488 Holding Wrench
EN-955 Locking Pin
For equivalent regional tools, refer to Special Tools.
Removal Procedure
Remove the right front wheelhouse liner. Refer to Front Wheelhouse Liner
Replacement (Trax) ,
Front Wheelhouse Liner Replacement (Encore)
Fig. 4: Air Conditioning Compressor (2H0)
Air Conditioning Compressor Replacement (2H0)
COMPRESSOR LEAK TESTING (R-134A)
Special Tools
GE-39400-A Halogen Leak Detector
GE-41447 R-134A A/C Tracer Dye-Box of 24
GE-42220 Universal 12V Leak Detection Lamp
GE-43872 Fluorescent Dye Cleaner
GE-