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Spongy brake pedal on 2017 Acura MDX - Time for a brake fluid flush?

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Jennifer H. · rep 0 · May 22, 4:59 AM · 1 replies · solved · Question

Vehicle: 2017 Acura MDX Advance

Hello Acura community,

I own a 2017 Acura MDX with about 80,000 miles on it. Lately, I've noticed that my brake pedal feels a bit spongy, and I have to press it down further than usual to get a firm stop. The braking performance itself seems okay, but the feel isn't what it used to be.

I've never had the brake fluid flushed since I bought the car. Is this a common issue for older brake fluid? What's the recommended service interval for a brake fluid flush on these MDXs? Is this something I can do in my garage, or should I take it to a shop?

Thanks for any insights!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:59 AM

0

ClearTheCode admin answer:

Your observation of a spongy brake pedal on your 2017 Acura MDX, especially with 80,000 miles and no prior brake fluid flush, strongly suggests that it's time for this critical maintenance. Brake fluid is hygroscopic, meaning it absorbs moisture over time, which can lead to the symptoms you're experiencing.

  1. Recommended Interval: Acura generally recommends a brake fluid flush every 3 years or 45,000 miles, whichever comes first, for most of their vehicles, including your MDX. Given your vehicle's age and mileage, you are well overdue for this service.

  2. Causes of Spongy Pedal:

    • Moisture Contamination: As brake fluid absorbs water, its boiling point decreases. When brakes are used heavily, the fluid can heat up, causing the absorbed water to boil and create vapor bubbles. Unlike fluid, vapor is compressible, leading to a spongy pedal feel.
    • Corrosion: Water in the brake system can also lead to internal corrosion of brake lines, calipers, and the master cylinder, potentially causing leaks or component failure over time.
    • Degraded Fluid: Over time, additives in the brake fluid break down, reducing its effectiveness.

  3. DIY vs. Professional: A brake fluid flush is a moderately challenging DIY task that typically requires two people (one to pump the pedal, one to bleed the calipers) or specialized pressure bleeding equipment. It's crucial to use the correct DOT3 or DOT4 fluid (check your owner's manual for the exact specification) and to prevent air from entering the system. If done incorrectly, you could introduce air into the brake lines, making the problem worse and potentially compromising braking safety. For most owners, especially those without prior experience, a professional service is recommended.

  4. When to See a Shop:

    • If you're not confident in performing the flush yourself, or if you don't have the necessary tools or a helper, a professional can ensure the job is done safely and correctly.
    • If a brake fluid flush doesn't resolve the spongy pedal, it could indicate more serious issues such as a failing master cylinder, air in the ABS module, or a leak in the brake lines. In such cases, immediate professional diagnosis and repair are essential for your safety.
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