Chevrolet Trax: Brake assist system description and operation
System Component Description
The brake assist system consists of the following:
Brake Pedal
Receives, multiplies and transfers brake system input force from driver.
Brake Pedal Pushrod
Transfers multiplied input force received from the brake pedal to the vacuum brake booster.
Vacuum Brake Booster
Uses source vacuum to decrease effort required by driver when applying brake system input force. At rest, source vacuum is applied to both sides of the vacuum diaphragm for single booster. Return springs maintain the booster in a rest position. When brake system input force is applied, vacuum to the rear of the diaphragm is cut off, and air at atmospheric pressure is admitted in its place. This provides a decrease in brake pedal effort required. When input force is removed, vacuum again replaces atmospheric pressure within the booster.
Vacuum Source
Supplies force used by vacuum brake booster to decrease brake pedal effort. The source vacuum for a spark ignition engine is normally derived from the intake manifold
Vacuum Source Delivery System
Enables delivery and retention of source vacuum for vacuum brake booster.
System Operation
Under normal driving conditions, without the brakes applied, vacuum is allowed to act on both sides of the diaphragm within the vacuum brake booster. When the brake pedal is applied, the effort by the driver is multiplied due to the relative length of the brake pedal in relationship to its pivot point and the point at which the push rod to the vacuum brake booster is attached.
Movement of the push rod causes a valve within the vacuum brake booster to close between the two sides of the diaphragm, thus isolating each side. It also allows a valve to open that allows atmospheric pressure to act on the pedal side of the vacuum brake booster while maintaining vacuum on the vacuum source side of the diaphragm.
The movement of the brake pedal pushrod is transferred to the hydraulic brake master cylinder via the vacuum brake booster. The pressure differential within the vacuum brake booster reduces the effort required by the driver in applying the brakes.
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Brake booster vacuum assist description and operation
Hydraulic Brakes Block Diagram
Fig. 193: Hydraulic Brakes Block Diagram
In order to assure that vacuum is available to the vacuum brake booster, the
car can contain a vacuum pump
either in additi
Hydraulic brake system description and operation
System Component Description
The hydraulic brake system consists of the following:
Hydraulic Brake Master Cylinder Reservoir
Contains a supply of brake fluid for the hydraulic brake system.
Hydraulic
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Shoulder Belt Height Adjuster
The vehicle has a shoulder belt
height adjuster for the driver and
right front passenger seating
positions.
Adjust the height so the shoulder
portion of the belt is on the shoulder
but not falling off of it. The belt
should be close to but not
contacting the neck. Improper
shoulder belt height adju
Antilock Brake System (ABS)
ABS (If Equipped) is an advanced
electronic braking system that helps
prevent a braking skid.
When the vehicle begins to drive
away, ABS checks itself.
A momentary motor or clicking noise
might be heard while this test is
going on, and it might even be
noticed that the brake pedal moves
a little.
