Pinpoint Test J: Excessive/Erratic Brake Pedal Travel

WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 2015 Jaguar XKR-S, 2015 Jaguar XKR, 2015 Jaguar XK, 2014 Jaguar XKR-S, and 2014 Jaguar XKR. However, it is still accessible from the selected car via links, so may be relevant.

J1: TEST ON ROUGH ROAD
1. Road test the vehicle on rough road conditions.
2. Apply the brakes slowly.
Is the brake pedal effort and brake pedal travel normal?
- Yes : Vehicle is OK.
- No : GO to J2.
J2: CHECK BRAKE FLUID LEVEL
1. Check the brake master cylinder reservoir fluid level.
  Is the fluid level OK?
- Yes : GO to J3.
- No : CHECK brake master cylinder reservoir sealing points. For additional information, refer to BRAKE MASTER CYLINDER component test. ADD brake fluid and BLEED the brake system.
Refer to: Brake System Bleeding - Vehicles Without: Carbon Ceramic Brakes (General Procedures). TEST the system for normal operation.
J3: CHECK BRAKE PEDAL RESERVE
1. Run engine at idle speed.
2. Apply the brake pedal lightly three or four times.
3. Wait 15 seconds for the vacuum to replenish.
4. Push down on the brake pedal until it stops moving downward or an increased resistance to the brake pedal travel occurs.
5. Hold the brake pedal in the applied position while increasing the engine speed to 2000 revs/min.
6. Release the accelerator pedal.
Does the brake pedal move downward as the engine speed returns to idle?
- Yes : GO to J4.
- No : CHECK the vacuum to the brake booster.
J4: CHECK THE FRONT WHEEL BEARING ASSEMBLY
1. Check the front wheel bearing assembly.
  Are the front wheel bearings loose?
  - Yes : INSTALL a new front wheel bearing if damaged.
    Refer to: Front Wheel Bearing and Wheel Hub - V8 N/A 4.2L Petrol/V8 S/C 4.2L Petrol or Front Wheel Bearing And Wheel Hub - V8 N/A 5.0L Petrol/V8 S/C 5.0L Petrol (Removal and Installation).
    
    TEST the system for normal operation.
  - No : CHECK the front brake discs for thickness variances.