Inspection and testing of brakes (Discovery 3)

1. Make sure the customer's complaint is justified. If a road test is required, check that the condition of the vehicle allows for a safe test.

If a road test is required, check that the condition of the vehicle allows for a safe test.

2. Visually inspect for obvious mechanical problems.

Mechanical factors

• Condition and installation of the brake pad (OK)
• Condition and installation of the brake caliper (ov)
• Condition and installation of the brake disc (ov)
• Disk status and installation (ov) / drum (ov) parking brake
• Condition and installation of parking brake pads
• Cable condition and installation (ov) parking brake
• Condition and installation of the vacuum brake booster
• Condition and installation of a vacuum hose of the vacuum amplifier of brakes
• Condition and installation of the main brake cylinder
• Hydraulic control box (HCU)
• Brake fluid leaks
• Brake warning lamp

3. If an obvious cause of a problem that you identified or described by the customer is found, resolve it before proceeding to the next steps (if possible).

4. Use an approved diagnostic system or scan tool (tester), to retrieve all diagnostic trouble codes before accessing the symptom table (DTC). Behind the list of diagnostic trouble codes (DTC), related to anti-lock brakes, refer to section 206-09 "Traction control" in the workshop manual.

Behind the list of diagnostic trouble codes (DTC), related to anti-lock brakes, refer to section 206-09 "Traction control" in the workshop manual. Clear all DTCs after troubleshooting.

Symptom	Possible reasons	Action
Noise in the brakes	stones brake pads Brake disk (And)	Refer to the relevant section in the workshop manual.
Vibration in the brakes	Suspension elements Brake disk (And)	Refer to the relevant section in the workshop manual.
Increased brake pedal travel/"soft" brake pedal	brake pads The presence of air in the brake system Master brake cylinder brake fluid leak (see visual inspection).	Worn brake pads can cause increased pedal travel, new brake pads can cause "softness" pedals. Check after running in the pads. Check pedal travel. If the pedal "fails", air is suspected in the system. Check for the cause of air intrusion and make any necessary repairs. If the pedal drops to the floor when depressed and there are no external leaks, a master cylinder failure is suspected. Refer to the relevant section in the workshop manual.
Increased effort on the brake pedal / "hard" brake pedal	brake pipeline (s) guide element (s) brake caliper Piston (neither) brake caliper Vacuum line brake system Vacuum brake pump Vacuum brake booster	Check the brake lines for damage. Check the brake calipers. Check the brake vacuum line for air leaks and make any necessary repairs. Check the operation of the vacuum pump of the brake system. Refer to the relevant section in the workshop manual. Check the vacuum brake booster.
Low foot brake performance/brake release/sticking/sticking	brake pipeline (s) brake pads Piston (neither) brake caliper guide element (s) brake caliper Brake disk (And)	Check the vehicle for damaged brake lines. Inspect the brake pads. Check the brake calipers. Check brake discs. Refer to the relevant section in the workshop manual.
Unable to engage or release parking brake / Poor performance / Stuck / deformed parking brake	Parking brake cables Parking brake pads Parking brake adjusters Rear brake disc (And) / drum (s) parking brake Parking brake actuator malfunction	Check cable operation/condition (ov) parking brake. Make sure the tip (And) cable is correctly connected to the lever (am). Inspect parking brake pads for wear. Check that the parking brake pads are properly adjusted. Check the rear brake disc (And) / drum (s) parking brake. Check the parking brake actuator for damage and/or excessive noise during normal operation. Refer to the relevant section in the workshop manual.
Brake warning light stays on	Brake fluid level in reservoir brake pads Brake pad wear sensor wires Brake fluid level sensor	Check the level and, if necessary, add brake fluid. Inspect the brake pads. Check the brake pad wear sensor circuit. Refer to the electrical manual. Check the operation of the brake pad wear sensor. Refer to the relevant section in the workshop manual.