Hydraulic/Mechanical - Disc Brakes

DISC BRAKES

Each front and rear hydraulic disc brake assembly consists of the following components:

- Disc brake caliper (4 piston opposed fixed)
- Brake shoes and linings
- Brake rotor

These components are described in detail below.










The disc brake caliper applies the brake pads (6, 18) to the brake rotor. This is done using a four-piston opposed fixed caliper at each corner of the vehicle. Each caliper body is cast aluminum, and is two individual pieces which are held together by 4 bolts (serviced as one assembly). Each caliper half houses two pistons; front calipers use 40 mm and 44 mm size pistons while rear calipers use 38 mm and 42 mm size pistons. Front caliper pistons are mounted in the caliper halves so that the smaller size piston is on the bottom and the larger size piston is on top when the caliper is mounted on the vehicle. Rear caliper pistons are mounted in the caliper halves so that the smaller size piston is on the top and the larger size piston is on bottom when the caliper is mounted on the vehicle. The two halves of the caliper are hydraulically connected by means of an external brake tube (14) on the bottom of the caliper assembly. Each caliper half has an individual bleeder screw at the top of the caliper half and each side must be individually bled. The caliper bolts directly to the steering knuckle of the vehicle by means of two machined mounting bosses on the inboard caliper half.

Two brake pads are used on each brake assembly, one on each side of the brake rotor. The brake shoe lining material is a semi-metallic non-asbestos formula. When installing brake shoes, install them in the caliper with the chamfered end against the direction the rotor rotates when the vehicle is traveling in the forward direction. That is, front brake shoes need to be installed with the chamfered end of the lining toward the lower end of the caliper; rear brake shoes need to be installed with chamfered end of the lining toward the upper end of the caliper. The brake lining material used has been specifically formulated to meet the braking requirements of this vehicle. When brake shoes are replaced, only brake shoes meeting the Original Equipment Manufacturer (OEM) formulation (such as Mopar(R) replacement parts) should be used to maintain the original braking performance of this vehicle.

Rear brake pads on ACR vehicles are the same as other vehicles with one exception. The brake pads with wear indicators are installed as the inboard pad to avoid contact with rotor. Like on other vehicles, the brake pads are installed with the chamfered end leading into the rotor rotation.

One 14 inch brake rotor is used on each brake assembly. It mounts on the hub and bearing. The rotor is made of iron and is vented to help cool it during brake applications. Front rotors have a different offset from rear rotors to help prevent mixing of front and rear brake rotors.





ACR vehicles feature two-piece lightweight slotted rotors. These rotors look distinctly different from the one-piece design used on the base vehicle. The disc portion (1) of the rotor is bolted to the hub (or hat) portion (2). Although the two can be separated, the rotor is serviced as one assembly. Also, ACR brake rotors are directional. Each rotor is marked for the corner of the vehicle it is to be installed on; example: RF = Right Front. This marking is located on the outer hat flange between the bolts attaching the disc to the hat.