Inspection And Verification: Notes
- If a control module or a component is at fault and the vehicle remains under manufacturer warranty, refer to the Warranty Policy and Procedures manual, or determine if any prior approval program is in operation, prior to the installation of a new module/component.
- When performing voltage or resistance tests, always use a digital multimeter accurate to three decimal places, and with an up-to-date calibration certificate. When testing resistance always take the resistance of the digital multimeter leads into account.
- Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.
- Verify the customer concern.
- Visually inspect for obvious signs of damage and system integrity.
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for Diagnostic Trouble Code(s) (DTC) and refer to the DTC Index.
- Check the Jaguar Land Rover Claims Submission system for open campaigns. Refer to the corresponding bulletins and SSMs which may be valid for the specific customer complaint and the recommendations as required.
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Road Test
Complete a road test to compare actual vehicle braking performance with the performance standards expected by the driver. The ability of the test driver to make valid comparisons and detect performance deficiencies will depend on experience
The driver should have a thorough knowledge of brake system operation and accepted general performance guidelines to make good comparisons and detect performance concerns
An experienced brake technician will always establish a route that will be used for all brake diagnosis road tests. The roads selected will be reasonably smooth and level. Gravel or bumpy roads are not suitable because the surface does not allow the tires to grip the road equally. Crowned roads should be avoided because of the large amount of weight shifted to the low set of wheels on this type of road. When the route is established and consistently used, the road surface variable can be eliminated from the test results
Before a road test, obtain a complete description of the customer concerns or suspected condition. From the description, the technician's experience will allow the technician to match possible causes with symptoms. Certain components will be tagged as possible suspects while others will be eliminated by the evidence. More importantly, the customer description can reveal unsafe conditions which should be checked or corrected before the road test. The description will also help form the basic approach to the road test by narrowing the concern to specific components, vehicle speed or conditions
Begin the road test with a general brake performance check. Keeping the description of the concern in mind, test the brakes at different vehicle speeds using both light and heavy pedal pressure.
If the concern becomes evident during this check, verify it fits the description given before the road test. If the concern is not evident, attempt to duplicate the condition using the information from the description
If a concern exists, use the symptom chart in order to isolate it to a specific sub-system and condition description. From this description, a list of possible sources can be used to further narrow the cause to a specific component or condition
Uneven Brake Pad Wear
Expect variations in brake pad wear due to cooling airflow and other factors, the amount acceptable would depend on vehicle mileage and the technician's experience/judgement. Excessive variations in brake pad wear may also be due to mechanical, hydraulic or brake pad material issues
Brake Caliper leak Check
If a fluid leak is suspected, it may be due to leaked grease from behind the dust boot (grease is used as an aid during brake caliper assembly), remove the components to access the area and remove the excess grease from the brake pad back plate, the piston nose and the dust boots (as indicated). Brake cleaner will help remove the grease from the components. The original components can then be installed and a brake fluid leak test can be completed to confirm no leak is present.
- Apply the brake pedal firmly for a maximum of 5 applications.
- On completion of the fifth application check for leakage from the caliper pistons. If there is a leak present after the test install a new brake caliper Refer to: BRAKE CALIPER - VEHICLES WITH: 325 MM FRONT BRAKE DISCS or BRAKE CALIPER - VEHICLES WITH: 350 MM FRONT BRAKE DISCS .
Brake Symptom Chart
- Check the repair history of the vehicle to see if it has had any recent repairs. As this may be a contributing factor to the customer concern.
- Jaguar Land Rover braking systems are designed to achieve peak performance under a broad range of driving conditions. Jaguar Land Rover's priority is the safety of its braking systems, and they are designed to perform in all circumstances, however the brake may, dependent on the environment and driving style, produce the occasional noise. This does not impair the operation or performance. Brake noise is an issue facing many vehicle manufacturers and Jaguar Land Rover are constantly working in conjunction with the leading brake caliper and brake pad suppliers to develop design solutions which reduce brake squeal noises.
| SYMPTOM | POSSIBLE CAUSES | ACTION |
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| Brake noise/squeal |
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| Premature brake pad wear |
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| Uneven brake pad wear |
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| Brake vibration/judder |
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| Brake Disc Corrosion |
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| Excessive brake pedal travel/brake pedal spongy |
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| Excessive brake pedal effort/brake pedal hard |
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| Low foot brake efficiency/brakes pulling/sticking/binding |
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| Brake warning indicator illuminated |
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