Disc Brake Caliper (Front) Explanation

DISC BRAKE CALIPER DESCRIPTION
The calipers are a single piston type. The calipers are free to slide laterally, this allows continuous compensation for lining wear.

DISC BRAKE CALIPER OPERATION
When the brakes are applied fluid pressure is exerted against the caliper piston. The fluid pressure is exerted equally and in all directions. This means pressure exerted against the caliper piston and within the caliper bore will be equal

Fluid pressure applied to the piston is transmitted directly to the inboard brake shoe. This forces the shoe lining against the inner surface of the disc brake rotor. At the same time, fluid pressure within the piston bore forces the caliper to slide inward on the mounting bolts. This action brings the outboard brake shoe lining into contact with the outer surface of the disc brake rotor.

In summary, fluid pressure acting simultaneously on both piston and caliper, produces a strong clamping action. When sufficient force is applied, friction will attempt to stop the rotors from turning and bring the vehicle to a stop.

Application and release of the brake pedal generates only a very slight movement of the caliper and piston. Upon release of the pedal, the caliper and piston return to a rest position. The brake shoes do not retract an appreciable distance from the rotor. In fact, clearance is usually at, or close to zero. The reasons for this are to keep road debris from getting between the rotor and lining and in wiping the rotor surface clear each revolution.

The caliper piston seal controls the amount of piston extension needed to compensate for normal lining wear.

During brake application, the seal is deflected outward by fluid pressure and piston movement.. When the brakes (and fluid pressure) are released, the seal relaxes and retracts the piston.

The amount of piston retraction is determined by the amount of seal deflection. Generally, the amount is just enough to maintain contact between the piston and inboard brake shoe.

FRONT DISC BRAKE CALIPER REMOVAL
1. Install prop rod on the brake pedal to keep pressure on the brake system, Holding pedal in this position will isolate master cylinder from hydraulic brake system and will not allow brake fluid to drain out of brake fluid reservoir while brake lines are open. This will allow you to bleed out the area of repair instead of the entire system.
2. Raise and support vehicle.
3. Remove front wheel and tire assembly.
4. Drain small amount of fluid from master cylinder brake reservoir with clean suction gun.
5. Bottom caliper pistons into the caliper (Fig 1) #4 by prying the caliper over.
6. Remove brake hose banjo bolt and gasket washers (Fig 1) #1. Discard gasket washers.
7. Remove the caliper slide bolts (Fig 1) #3.
8. Remove the caliper (Fig 1) #4 from the adapter.

CAUTION; Never allow the disc brake caliper to hang from the brake hose. Damage to the brake hose will result. Provide a suitable support to hang the caliper securely

FRONT DISC BRAKE CALIPER INSTALLATION
1. Install the caliper (Fig 1) #4 on the adapter.
2. Caliper slide pins should be free from debris and lightly lubricated.
3. Install the caliper slide pin bolts (Fig 1) #3 and tighten to 35 N.m (26 ft. lbs.).
4. Gently lift one end of the slide pin boot to equalize air pressure, then release the boot and verify that the boot is fully covering the slide pin.
CAUTION: Verify brake hose is not twisted or kinked before tightening banjo bolt.
5. Install brake hose banjo bolt (Fig 1) #1 to caliper #4 with new copper washers and tighten banjo bolt (6) to 31 N.m (23 ft. lbs.).
6. Verify brake fluid level.
7. Remove the prop rod from the brake pedal.
8. Bleed the area of repair for the brake system, If a proper pedal is not felt during bleeding an area of repair then a base bleed system must be performed. Refer to STANDARD PROCEDURE
9. Install wheel and tire assemblies.
10. Remove supports and lower vehicle.