Pulsating Brakes and Squealing on my 2018 XC90 T6

ClearTheCode admin answer:

It sounds like you're dealing with a common brake issue that often points to worn components. Here's a breakdown of potential causes and what to do:

1. Pulsating Brake Pedal:

   • Causes: The most common cause for a pulsating brake pedal is warped brake rotors. When rotors overheat, they can develop uneven surfaces, causing the brake pads to grab inconsistently as the rotor spins. This translates to the pulsation you feel through the pedal. Less common causes could be issues with the ABS system or a seized caliper, but warped rotors are usually the culprit.
   • Diagnosis: A mechanic will typically measure the runout of your rotors to confirm if they are warped. They will also inspect the calipers for proper function.

2. Brake Squealing:

   • Causes: Squealing brakes can be due to several factors:
     • Worn Brake Pads: Many pads have a wear indicator that makes a high-pitched squeal when they're nearing the end of their life.
     • Glazed Pads/Rotors: If pads or rotors get too hot, their surfaces can become glazed, leading to noise.
     • Contamination: Dirt, dust, or even brake fluid on the pads or rotors can cause squealing.
     • Improper Installation: Sometimes, new pads can squeal if they weren't properly bedded in or if anti-squeal shims weren't used.

3. When to See a Shop:

   • You should have your vehicle inspected by a qualified mechanic as soon as possible. While a pulsating pedal and squealing might not indicate immediate catastrophic failure, they are signs of compromised braking performance. Driving with warped rotors can lead to longer stopping distances and increased wear on other brake components. A mechanic can accurately diagnose the issue, which will likely involve replacing brake pads and rotors, and potentially inspecting or servicing the calipers. Ignoring these symptoms can lead to more expensive repairs down the line or, more importantly, reduced safety.