Brake Fluid Renewal

Why The Clock Matters

Brake fluid is hygroscopic: it pulls water from the air. Water lowers the boiling point and corrodes the hydraulics from the inside. Change it every two years whether the mileage is high or low. Use Super DOT 4, paraffin-free, to Jaguar ESA-M6C25-A. Open bottles go stale; buy sealed and finish the job from that bottle.

Shared Reservoir

One reservoir on the left of the bay feeds the brakes and the hydraulic clutch. When you renew the fluid you empty that circuit as well. Syphon the reservoir clear of the old fluid before you start pushing fresh fluid through, so the first push is not just old stock diluted.

Bleed Until Clean

Work like a normal hydraulic bleed, but keep going at each nipple until the fluid that leaves is clean and free of bubbles, not until the pedal merely firms up. Hit every caliper bleed screw in turn. Then bleed the clutch slave so the shared fluid is new end to end. Keep the reservoir topped above MIN the whole time; air sucked in at the cap undoes the work.

• Fresh sealed Super DOT 4 only. Never top with a random DOT 5 silicone or a half-empty can from last year.
• Catch the waste. Old fluid strips paint and is not reusable.
• If a nipple will not open, stop before you round it. Seized screws are a caliper job, not a force fit.

When finished, pump the pedal until it feels firm, check for wet unions, and road-test carefully. A soft pedal after a fluid change means air is still in the lines: bleed again before you trust a hard stop.