If you’re experiencing a hard brake pedal in your Jaguar XJS, it might be a straightforward fix. Here’s a simple guide to diagnosing and resolving the issue.

Step 1: Add Mineral Oil

1. Add Mineral Oil: Begin by adding mineral oil in your brake system to the reservoir until it reaches the recommended level. For the Jaguar XJS, you should use JLM9886 Mineral Oil. Low oil levels can cause the brake pedal to feel hard and reduce the effectiveness of your power brakes.

Step 2: Check the Brake Accumulator

If adding mineral oil doesn’t resolve the issue, the next step is to check the brake accumulator. This component is crucial for maintaining power brake function and may need replacement if faulty.

1. Identify Your Model

  • For 1988-1989 XJ6 models, the part number for the brake accumulator is JLM11659.
  • For 1990-1994 XJ6 models, the part number is JLM1907.

2. Replace the Brake Accumulator: If you continue to experience a hard brake pedal and feel like you no longer have power brakes, the brake accumulator may have failed. Replace it with the correct part for your specific model.

See our Jaguar Parts Store Catalog to order parts.