Symptom Troubleshooting Chart - Conventional Brake System

SYMPTOM TROUBLESHOOTING CHART - CONVENTIONAL BRAKE SYSTEM

Problem	Possible Cause	Action
The red brake warning indicator is always on	Brake fluid level	Fill the brake fluid reservoir to the MAX line.
The red brake warning indicator is always on	Circuit Instrument cluster	See INSTRUMENT CLUSTER .
Red brake warning indicator inoperative	Circuit Bulb	See INSTRUMENT CLUSTER , .
The brakes pull or drift	Tire air pressure	Check the tires for uneven or excessive wear, and correct inflation.
	Brake pads Brake components	Check the brake pads for uneven taper or excessive wear. Repair as necessary. Check the brake discs and the hubs for damage. Repair as necessary.
	Suspension components Wheel alignment	Check suspension components. See FRONT SUSPENSION or see REAR SUSPENSION . Check wheel alignment. See WHEEL ALIGNMENT PREINSPECTION .
Brake pedal goes down fast	Brake fluid level	Inspect the system for leaks. Fill the brake master cylinder reservoir. Bleed the system. See BRAKE SYSTEM BLEEDING .
	Air in system	Inspect the system for leaks. Bleed the system. See BRAKE SYSTEM BLEEDING
	Brake master cylinder	Carry out the brake master cylinder component test. See COMPONENT TESTING .
The brake pedal eases down slowly	Air in system	Inspect the system for leaks. Bleed the system. See BRAKE SYSTEM BLEEDING
The brake pedal eases down slowly	Brake master cylinder	Carry out the brake master cylinder component test. See COMPONENT TESTING .
Brake lockup under light brake pedal force	Brake pads	Check the brake pads for uneven taper or excessive wear. Repair as necessary.
	Brake component	Check the brake components for correct operation. Repair as necessary.
	Parking brake component	Repair or install new components as necessary. See PARKING BRAKE SYSTEM .
	Anti-lock brake control system	Check the anti-lock brake control system. See ANTI-LOCK BRAKE SYSTEM (ABS) DIAGNOSIS .
Excessive/erratic brake pedal travel	Leak in hydraulic system Air in system Disc brake caliper	Inspect the system for leaks. Bleed the system. See BRAKE SYSTEM BLEEDING . Repair or install new brake calipers as necessary. See BRAKE CALIPER .
	Brake master cylinder	Carry out the brake master cylinder component test. See COMPONENT TESTING .
	Brake pads	Check the brake pads for excessive wear. Install new brake pads as necessary. See BRAKE PADS .
	Brake pedal	Check the brake pedal for binding or obstructions. Repair as necessary. See BRAKE PEDAL AND BRACKET .
Brakes drag	Parking brake component	Repair or install new components as necessary. See PARKING BRAKE SYSTEM .
	Brake caliper guide pins	Repair or install new caliper guide pins, seals and boots. See HYDRAULIC BRAKE ACTUATION .
	Disc brake caliper	Repair or install new brake calipers as necessary. See BRAKE CALIPER .
	Drum brake component	Repair or install new drum brake components as necessary. See HYDRAULIC BRAKE ACTUATION .
	Brake booster	Carry out the brake booster component test. See COMPONENT TESTING .
	Brake master cylinder	Carry out the brake master cylinder component test. See COMPONENT TESTING .
Excessive brake pedal effort	Brake booster	Carry out the brake booster component test. See COMPONENT TESTING .
	Brake booster check valve	Carry out the check valve component test in this section. See COMPONENT TESTING .
	Brake booster manifold vacuum hose	Reroute, repair or install new components as necessary.
Rattling noise	Caliper mounting bolts loose	Check the caliper bolts. Tighten to specifications. See BRAKE SPECIFICATIONS
	Damaged or worn caliper guide pins or retainers	Check the caliper guide pins and retainers for lubrication and correct operation. Lubricate or install new components as necessary See HYDRAULIC BRAKE ACTUATION .
	Missing or damaged anti-rattle clips or springs	Check the brake pads for missing clips or broken springs Install new components as necessary See HYDRAULIC BRAKE ACTUATION .
	Loose brake disc shield	Tighten the brake disc shield bolts to specification. See BRAKE DISC SHIELD .
Clicking noise - with brakes applied with ABS brakes	ABS hydraulic control unit	Acceptable condition
Squealing noise - occurs on first (morning) brake application	Brake pads/shoes	Acceptable condition. Caused by humidity and low brake pad temperature.
Squealing noise - a continuous squeal	Brake pads or shoes worn below minimum thickness	Inspect brake pads/shoes for excessive wear, taper wear or uneven wear. Verify brake pads/shoes are within minimum specifications. See HYDRAULIC BRAKE ACTUATION .
Squealing noise - an intermittent squeal brought on by cold, heat, water, mud or snow	Brake pad	Acceptable condition.
Groaning noise - occurs at low speeds with brake lightly applied (creeping)	Brake pads	Acceptable condition
Grinding noise - continuous	Brake pads or shoes worn below minimum thickness	Inspect the brake pads/shoes, brake discs/drums and attaching hardware for damage Verify brake pads/shoes are within minimum specifications. See HYDRAULIC BRAKE ACTUATION
Moaning noise	Brake linings contaminated with grease or oil	Inspect the brake pads and shoes for contamination. Repair or install new components as necessary. See HYDRAULIC BRAKE ACTUATION .
Vibration when the brakes are applied	Uneven brake pad wear Brake disc pad transfer Brake disc Suspension components	Complete the brake system inspection described in Inspection and Verification. See PINPOINT TEST 1: VIBRATION WHEN BRAKES ARE APPLIED .
Brake vibration/shudder - occurs when the brake pedal is released	Brake caliper guide pins	Inspect the brake caliper guide pins for correct operation. See HYDRAULIC BRAKE ACTUATION .
	Brake drag	Inspect the brake pads and shoes for premature wear. Repair or install a new caliper or wheel cylinder as necessary. See BRAKE CALIPER for front brakes or see WHEEL CYLINDER for rear brakes.