2018 Q50 Pulsating Brakes - Vibration when stopping, what's going on?

Hi Sarah,

The pulsating sensation you're describing when braking is a very common issue, particularly with vehicles that have some mileage on them. It almost always points to an issue within your braking system. Here's a breakdown of potential causes and what to do:

1. Warped or Unevenly Worn Rotors: This is the most frequent cause of brake pulsation. Rotors can develop variations in thickness or become 'warped' (more accurately, they develop uneven friction material deposits or hot spots) due to excessive heat from heavy braking or improper break-in procedures after new pad installation. When the brake pads clamp down on an uneven surface, it translates to a pulsation you feel in the pedal and steering wheel.
2. Sticky Calipers: If a brake caliper piston or slide pin is sticking, it can cause the brake pad to remain in contact with the rotor, generating excessive heat and uneven wear on both the pad and rotor. This can lead to the same pulsation symptoms.
3. Uneven Brake Pad Wear: While less common to cause pulsation on its own, severely uneven pad wear can contribute to rotor issues and a less consistent braking feel.
4. Loose Suspension Components: Although less likely to be the primary cause of a brake-specific pulsation, worn tie rod ends, control arm bushings, or wheel bearings can amplify vibrations during braking, making the issue feel worse.

What to do:

1. Inspection: The first step is a thorough visual inspection. Jack up the front of your 2018 Infiniti Q50 and check the rotors for visible grooves, scoring, or discoloration (blue/purple spots indicate extreme heat). Check the brake pads for even wear. Try to wiggle the wheel to check for play in the wheel bearings or suspension components.
2. Rotor Runout: A mechanic will use a dial indicator to measure rotor runout (how much the rotor wobbles as it spins). If runout is beyond specifications, the rotors need to be resurfaced (if enough material remains) or replaced.
3. Caliper Check: Ensure the calipers are moving freely on their slide pins. If they are seized, they'll need to be serviced or replaced.

When to see a shop:

Given that you're feeling a significant pulsation, it's highly recommended to have your Infiniti Q50 inspected by a professional mechanic as soon as possible. While often not an immediate catastrophic failure, compromised braking performance is a serious safety concern. They can accurately diagnose whether it's warped rotors, a sticking caliper, or another issue, and recommend the appropriate repair, which will likely involve replacing or machining your front rotors along with new brake pads.