Chevrolet Cobalt Service & Repair Manual: Adjustments
| These brakes have self-adjusting
shoe mechanisms that ensure proper lining-to-drum clearances at all times.
The automatic adjusters operate only when the brakes are applied as the
vehicle is moving rearward. |
| An initial adjustment is required
after the brake shoes have been relined or replaced, or when the length
of the adjusting screw has been changed during service operations. |
| Frequent usage of an automatic
transmission forward range to halt reverse vehicle motion may prevent the
automatic adjusters from functioning, thereby inducing low pedal heights.
Should low pedal heights be encountered, it is recommended that numerous
forward and reverse stops be made until satisfactory pedal height is obtained.
If a low pedal condition cannot be corrected by making numerous reverse
stops (provided the hydraulic system is free of air) it indicates that the
self-adjusting mechanism is not functioning. It will be required to remove
the brake drum, clean, free up and lubricate the adjusting mechanism. Then
adjust the brakes as follows, ensuring the parking brake is fully released. |
Service Brake
| Brake adjustment cannot be performed
with the drums installed. The following procedure is mandatory after new
linings are installed, or when the length of the brake shoe adjusting screw
has been changed. |
| 1. |
With brake drums removed, position
caliper to inside diameter of drum and tighten clamp screw, Fig.
1. |
| 2. |
Position brake shoe end of caliper
tool over brake shoes, Fig. 2. |
| 3. |
Rotate gauge slightly around shoes
to ensure gauge contacts linings at largest diameter. |
| 4. |
Adjust brake shoes until outside diameter
is .030 inch less than drum's inside diameter. If brake shoe
must be backed off, hold adjuster lever away from adjuster screw,
Fig. 3. |
|
Parking Brake
| On these brake systems, no adjustment
is required. These models have a self-adjusting parking brake system and
it should not be adjusted or modified in any way. |
| Fully applying and releasing the
parking brake 4-6 times the system will perform its self-adjustment procedure. |
Fig. 1 Brake drum measurement
Fig. 2 Brake shoe measurement
Fig. 3 Brake shoe adjustment
Removal
1.
Raise and support rear of vehicle,
then remove tire and wheel assembly.
2.
Mark drum and axle hub, then remove
brake dr ...
See also:
Chevrolet Cobalt Service & Repair Manual. General Service
Two basic types of power assist
mechanisms are used: vacuum assist diaphragm assemblies, which use engine
vacuum or in some cases vacuum pressure developed by an external vacuum
pump. The second type is a hydraulic pressure assist mechanism, which use
pressure developed by an ...
Chevrolet Cobalt Owners Manual
Chevrolet Cobalt Service Manual
Drum Brakes
Brake Service