Description And Operation: Description: Notes
ELECTRIC PARK BRAKE (EPB) SWITCH - ELECTRONIC TRANSMISSION SHIFTER
The EPB switch is used by the driver to apply and release the EPB, and is installed in the center console adjacent to the gear lever.
Slots on the sides of the EPB switch engage with the top panel of the center console, and a screw secures the EPB switch in position. An electrical connector on the back of the switch provides the interface with the vehicle wiring. A brake symbol on the switch illuminates when the exterior lamps are selected on.
There are three states for the parking brake switch:
- Apply request, when the handle of the EPB switch is pulled up.
- Release request, when the handle of the EPB switch is pushed down.
- Idle, when the handle of the EPB switch is in the central or rest position.
Microswitches, incorporated into the EPB switch, are activated by the handle of the EPB switch. To determine the operating state of the EPB switch, the EPBCM scans the circuits containing the microswitches.
DRUM BRAKES
| ITEM | DESCRIPTION |
|---|---|
| 1 | Wedge adjuster screw |
| 2 | Return spring |
| 3 | Cross strut |
| 4 | Backplate |
| 5 | Brake shoe |
| 6 | Shoe locating pin and clip |
| 7 | Adjuster spring |
| 8 | Toothed wheel adjuster |
| 9 | Dust shield |
| 10 | Rear brake disc |
| 11 | Adjuster access plug |
Each drum brake consists of a pair of brake shoes installed on a backplate attached to the rear hub carrier. The brake shoes operate on the drum integrated into the rear brake disc. The orientation of the brake shoes differ by 180° between the left and right brakes.
When the EPBCM tensions the brake cables, the movement is transmitted to an operating lever on one of the brake shoes. The operating lever pivots against a cross strut, which forces the brake shoes apart and into contact with the drum in the rear brake disc. Brake shoe to drum clearance is set with two manual adjusters, which are accessed through a hole in the brake disc. One of the adjusters is a conventional toothed wheel adjuster. The second adjuster is a wedge adjuster operated by an Allen screw.
After replacement of the brake shoes or brake discs, a bedding in procedure must be performed to ensure the drum brakes operate satisfactorily.
Prior to removing a brake disc from a vehicle, power should be disconnected from the EPBCM. Operation of the EPB switch while a brake disc is removed can cause the actuating mechanism in the EPBCM to seize.