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Soft/Spongy Brake Pedal on 2019 S90 T6

0

Eric V. · rep 0 · May 22, 5:13 AM · 1 replies · solved · Question

Vehicle: 2019 Volvo S90 T6 Inscription

Hi all,

I've noticed a worrying change in the brake pedal feel on my 2019 Volvo S90 T6 Inscription. It has about 55,000 miles. The pedal feels much softer and spongier than it used to, and I have to push it down further to get the same braking power. It almost feels like there's air in the lines, and the stopping distance seems to have increased slightly.

There are no warning lights on the dash, and I don't hear any grinding or squealing. I checked the brake fluid reservoir, and it looks to be at the correct level. What could be causing this sudden change in pedal feel? Is this something I can check myself, or does it require professional attention?

Thanks for your help!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:13 AM

0

ClearTheCode admin answer:

A soft or spongy brake pedal is a serious concern as it directly impacts your vehicle's stopping ability. Even without warning lights, this symptom requires immediate attention.

  1. Common Causes of a Soft/Spongy Brake Pedal:

    • Air in the Brake Lines: This is the most common cause. Air is compressible, unlike brake fluid, leading to a spongy feel as the air compresses before the fluid transmits pressure to the calipers. This can happen after brake work if the system wasn't bled properly, or if a leak allowed air in.
    • Brake Fluid Leak: Even a small leak in a brake line, caliper, wheel cylinder, or master cylinder can allow air into the system and reduce fluid pressure. While you checked the reservoir, a slow leak might not immediately show a significant drop.
    • Failing Master Cylinder: The master cylinder is responsible for generating hydraulic pressure. If its internal seals are worn, fluid can bypass them, leading to a soft pedal that might slowly sink to the floor when held down.
    • Worn Brake Pads/Rotors (less likely for spongy feel): While severely worn pads can increase pedal travel, they typically don't cause a spongy feel unless accompanied by other issues.
    • Faulty ABS/Stability Control Module (rare): In some cases, an internal fault within the ABS pump or module can affect brake pedal feel, though this is usually accompanied by warning lights.

  2. What You Can Do:

    • Visual Inspection: Carefully inspect all visible brake lines, calipers, and around the master cylinder for any signs of fluid leaks. Look for damp spots or drips.
    • Pump the Brakes: With the engine off, pump the brake pedal several times until it feels firm. Then, hold steady pressure on the pedal. If the pedal slowly sinks towards the floor, it's a strong indicator of a master cylinder issue or a significant leak.

  3. When to See a Shop:

    • Immediately: A soft or spongy brake pedal is a critical safety issue. Do not delay in getting this diagnosed and repaired. Your stopping power is compromised.
    • A professional technician will need to:
      • Inspect the entire brake system: This includes all brake lines, calipers, and the master cylinder for leaks.
      • Check for diagnostic trouble codes (DTCs): Although no lights are on, the vehicle's computer might have stored codes related to brake pressure or ABS system performance (e.g., C0040 - Brake Pressure Sensor Circuit, or specific Volvo codes related to the BCM - Brake Control Module).
      • Bleed the brake system: If air is present, a proper brake bleed (which might require specialized tools for ABS systems) will be performed.
      • Replace components: If a leak is found or the master cylinder is failing, those components will need replacement. Do not drive the vehicle extensively until this issue is resolved.
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