Front
DESCRIPTION - DISC BRAKES (FRONT)Each front disc brake consists of the following components:
^ Brake Rotor
^ Brake Caliper
^ Brake Caliper Adapter
^ Shoes (Pads)
There are two non-interchangeable front disc brake systems. One is manufactured by TRW and the other by Continental Teves.
CAUTION: Components used on the TRW brakes are not interchangeable with the Continental Teves brakes. The two different systems must not be mixed. Improper performance, noise and increased stopping distance can occur.
The TRW front brake caliper is a one piece casting containing a single 66 mm diameter piston bore (Fig. 4) with a phenolic piston. The caliper mounts to a caliper adapter using two guide pin bolts that thread into guide pins slid into the caliper adapter (Fig. 5). The pins are lubricated and have boots that seal them in place in the adapter.
The Continental Teves front brake caliper is a one piece casting containing a single piston 66 mm diameter bore (Fig. 4) with a phenolic piston. The caliper mounts to a caliper adapter using two guide pin bolts that thread into the caliper adapter and slide on bushings mounted in the caliper.
CAUTION: TRW and Continental Teves calipers are not interchangeable. Each caliper is specifically designed for the unique brake system. If calipers are interchanged, improper performance, noise and increased stopping distance can occur.
The two different brake calipers use different devices to control rattling. While the TRW brakes use spring clips that mount at the ends of the shoes in the adapters, Continental Teves brakes use a clip on the rear of the inboard pad to hold it to the piston and a larger clip on the outside of the caliper, holding it to the adapter (Fig. 6).
All brake caliper adapters mount to the steering knuckle in the same way using two mounting bolts.
The brake rotors are also different depending on brake system. The TRW front brakes utilize an inverted-hat style rotor. This rotor is externally vented meaning the inner most diameter of the braking disc vents to the outboard side (or face) of the rotor (Fig. 7). The Continental Teves front brakes utilize the familiar internally-vented hat style rotor.
Internally-vented refers to the fact that the inner most diameter of the braking disc vents to the inboard side of the rotor (Fig. 7).
CAUTION: Do not mix rotor types on the same vehicle. If brake rotors are mixed, noise and wear problems can result.
OPERATION - DISC BRAKES (FRONT)
When the brakes are applied, fluid pressure is sent to each brake caliper. The pressure at the caliper is exerted equally against the caliper piston. The pressure applied to the piston is transmitted directly to the inboard brake shoe. This forces the shoe lining against the inner surface of the brake rotor. At the same time, fluid pressure within the caliper piston bore forces the caliper to slide inward on its guide pins. This action brings the outboard shoe lining into contact with the outer surface of the brake rotor. This pressure on both sides of the brake rotor causes friction, bringing the vehicle to a stop.
When the brake pedal is released, so is the fluid pressure. The piston seal inside the caliper is designed to pull the piston back into the bore of the caliper when the brake pedal is released (Fig. 10). This action helps maintain the proper brake shoe-to-rotor clearance.
As disc brake shoe linings wear, master cylinder reservoir brake fluid level will drop. Adjust as necessary. Fluid level should always be checked after replacing shoes.