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Spongy Brakes on 2017 Navigator - Time for a Brake Fluid Flush?

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Chris P. · rep 0 · May 25, 4:31 AM · 1 replies · solved · Question

Vehicle: 2017 Lincoln Navigator L Reserve

My 2017 Lincoln Navigator L Reserve, with approximately 80,000 miles, has developed a somewhat spongy brake pedal feel over the past few months. It doesn't feel as firm or responsive as it used to, and I have to push the pedal down further to get the same braking power. I've had the brake pads and rotors checked recently, and they're in good shape.

Could old or contaminated brake fluid be the culprit here? What's the recommended interval for a brake fluid flush on a Navigator, and is this something a competent DIYer can tackle, or is it best left to a professional? I'm concerned about safety.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:31 AM

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ClearTheCode admin answer:

A spongy brake pedal on your 2017 Lincoln Navigator L Reserve with 80,000 miles, especially after confirming pads and rotors are good, strongly suggests an issue with your brake fluid. This is a critical safety concern that needs immediate attention.

  1. Brake Fluid Degradation: Brake fluid is hygroscopic, meaning it absorbs moisture from the air over time. Water in the brake fluid lowers its boiling point. When brakes get hot (e.g., during heavy braking or long descents), this water can boil and turn into compressible vapor. Since vapor compresses, it leads to a spongy pedal feel and reduced braking effectiveness. Contaminants can also build up, affecting system performance.

  2. Recommended Interval for Brake Fluid Flush: Lincoln, like many manufacturers, typically recommends a brake fluid flush every 2-3 years or 30,000-45,000 miles, whichever comes first. At 80,000 miles, if it hasn't been done, your fluid is almost certainly past due and likely contaminated.

  3. DIY vs. Professional Service:

    • DIY Considerations: While a brake fluid flush can be a DIY task, it requires precision and proper tools (e.g., a pressure bleeder or a second person for a two-person bleeding method). It's crucial to prevent air from entering the system and to use the correct DOT-rated fluid (likely DOT 3 or DOT 4 for your Navigator, check your manual/reservoir cap). Any mistake can compromise braking performance, which is a significant safety risk.
    • Professional Recommendation: Given that braking is a primary safety system, and you're experiencing symptoms, it's highly recommended to have a professional shop perform the flush. They have specialized equipment to ensure all old fluid is removed, the system is properly bled, and no air remains, restoring optimal braking performance.

  4. When to See a Shop (Immediately):

    • Spongy Pedal: Your current symptom is a red flag. Do not delay this service.
    • Brake Warning Light: If a brake warning light illuminates, pull over safely.
    • Any Braking Concern: Any change in brake feel, noise, or performance warrants immediate professional inspection. Driving with compromised brakes is extremely dangerous.
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