Inspection and testing of brakes (Discovery 3)

1. Ensure that the customer's complaint is justified. If a road test is required, ensure that the vehicle is in a safe condition to perform the test.

If a road test is required, ensure that the vehicle is in a safe condition to perform the test.

2. Visually inspect for obvious mechanical problems.

Mechanical factors

• Condition and installation of brake pads (ok)
• Condition and installation of brake caliper(s)
• Condition and installation of brake disc(s)
• Condition and installation of parking brake disc(s)/drum(s)
• Condition and installation of parking brake shoes
• Condition and installation of parking brake cable(s)
• Condition and installation of the brake booster
• Condition and installation of the brake booster vacuum hose
• Condition and installation of the master brake cylinder
• Hydraulic Control Unit (HCU)
• Brake fluid leaks
• Brake system warning light

3. If an obvious cause for a problem you have identified or a problem described by the customer is found, resolve it before moving on to further action. (if possible).

4. Use an approved diagnostic system or scanning device (tester) to extract all diagnostic trouble Codes (DTCs) before accessing the fault table. For a list of Diagnostic Trouble Codes (DTCs) related to the anti-lock braking system, refer to section 206-09 "Traction Control System" in the Service station manual.

For a list of diagnostic trouble codes (DTCs) related to the anti-lock brake system, refer to Section 206-09, Traction Control, in the service manual. Clear all DTCs after troubleshooting.

Sign of malfunction	Possible reasons	Action
Noise in the brakes	Stones Brake pads Brake disc(s)	Please refer to the relevant section in the service station manual.
Vibration in brakes	Suspension elements Brake disc(s)	Please refer to the relevant section in the service station manual.
Increased brake pedal travel/"soft" brake pedal	Brake pads Presence of air in the brake system Master brake cylinder Brake fluid leak (see visual inspection).	Worn brake pads may cause increased pedal travel, new brake pads may cause a "soft" pedal. Check after the pads have been broken in. Check the pedal travel. If the pedal "sinks", suspect air in the system. Check for the cause of the air intrusion and make any necessary repairs. If the pedal sinks to the floor when pressed and there are no external leaks, suspect a faulty master cylinder. Refer to the appropriate section in the workshop manual.
Increased brake pedal effort/"hard" brake pedal	Brake line(s) Brake caliper guide element(s) Brake caliper piston(s) Brake system vacuum line Brake system vacuum pump Vacuum brake booster	Check the brake lines for damage. Check the brake calipers. Check the brake system vacuum line for air leaks and perform the necessary repairs. Check the operation of the brake system vacuum pump. Refer to the corresponding section in the service station manual. Check the vacuum booster brakes.
Low efficiency of foot brake/brake drag/sticking/grabbing	Brake line(s) Brake pads Brake caliper piston(s) Brake caliper guide element(s) Brake disc(s)	Check the vehicle for damaged brake lines. Inspect the brake pads. Inspect the brake calipers. Inspect the brake discs. Refer to the appropriate section in the workshop manual.
Unable to engage or release parking brake / Poor performance / sticking / deformation of parking brake	Parking brake cables Parking brake shoes Parking brake adjusters Rear brake disc(s)/drum(s) parking brake Parking brake actuator malfunction	Check the operation/condition of the parking brake cable(s). Ensure that the cable end(s) are properly connected to the lever(s). Inspect the parking brake shoes for wear. Check that the parking brake shoes are adjusted correctly. Inspect the rear parking brake disc(s)/drum(s). Inspect the parking brake actuator for damage and/or excessive noise during normal operation. Refer to the appropriate section in the workshop manual.
The brake system warning light remains on	Brake fluid level in the reservoir Brake pads Brake pad wear sensor wires Brake fluid level sensor	Check the level and top up the brake fluid if necessary. Inspect the brake pads. Check the electrical circuit of the brake pad wear sensor. Refer to the electrical equipment manual. Check the operation of the brake pad wear sensor. Refer to the relevant section in the workshop manual.