2017-2019 Genesis G90 Brake Noise: Squeal, Grinding and Pulsation Causes

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most brake noise on a 2017-2019 Genesis G90 comes from three places: pads that are worn down to their wear indicators (a high squeal), metal-on-metal contact or a dragging caliper (grinding), and rotors with uneven thickness from hub rust or poor installation (pulsation). Genesis published a brake service bulletin for the 2017 and 2018 G90 that spells out the shop practices that prevent all three, and following it is the difference between a quiet brake job and a comeback.

How the G90 brake system is built

The first-generation G90 is a heavy, full-size luxury sedan. The base 3.3T twin-turbo V6 makes 365 horsepower and 376 lb-ft of torque, and a V8 was offered as well, so the brakes work hard stopping a lot of mass. All four corners use disc brakes. The owner's manual covers a disc brake wear indicator, an Electronic Parking Brake (EPB) and an Auto Hold function, which matters when you service the rear brakes.

Genesis Technical Service Bulletin 21-BR-002HG (March 2021), which applies to all 2017 and 2018 G80 and G90 models, has separate front procedures for floating calipers and for fixed calipers, plus a rear procedure for EPB-equipped cars. Before you buy parts, look at your own front caliper: a floating caliper slides on pins, while a fixed caliper is bolted solid and has pistons on both sides of the rotor. The 2019 G90 is the same first-generation car, so the bulletin is a sensible baseline for it too, but confirm the details for your VIN in the factory service manual.

Squeal: what it means and how to find it

A thin, high-pitched squeal is the most common G90 brake complaint. Wagner's technical guidance is blunt about the root cause: vibration is the main source of noise in a brake system, and that vibration comes from rust, loose parts and worn hardware that no longer holds the pad tightly. Bendix adds that as rotors heat up they can develop hot spots with different friction levels, and those torque changes across the rotor face excite the pad and caliper.

Work through these checks in order:

• Squeal with the pedal released that goes away when you brake: often the wear indicator touching the rotor. Measure pad thickness right away.
• Squeal only at light pedal pressure: usually pad vibration. Look for missing or reused shims, tired pad retainers or springs, and rust on the caliper where the pad ears sit.
• Squeal right after a brake job: often shims that were reused, grease on the pad backing plate, or pads that were never burnished.
• Squeal on one corner only: check that caliper for a sticking pin or piston and uneven pad wear.

The Genesis bulletin is specific on the hardware side: never reuse shims on new pads, always use the retainers (floating calipers) or pad springs (fixed calipers) supplied with the new pads, and do not put grease on the pad backing plate unless the shop manual says to, because it can trap debris and increase the chance of noise or dragging. If your pads did not come with fresh hardware, add a brake hardware kit to the order.

Grinding: metal contact and dragging calipers

Grinding is more urgent than squeal. A harsh, gritty grind when braking usually means the friction material is gone and the steel backing plate is cutting into the rotor. At that point the rotor is damaged and both pads and rotors on that axle need to be replaced.

Grinding or a hot smell with the brakes released points to a caliper that is not letting go. The bulletin calls out two causes you can check yourself:

• Slide pins (floating calipers): Genesis says to remove, clean and inspect the pins and boots and apply the specified silicone paste. It also warns against over-lubricating, because excess grease can trap air at the end of the pin and create an "air spring" that makes the caliper drag on the rotor.
• Guide pins (fixed calipers): clean them with a non-abrasive method and inspect for corrosion or bending that stops the pads moving freely. Genesis does not recommend greasing these pins unless the shop manual says so.

Also check for fluid at the caliper. The bulletin describes a simple test: wipe the fluid across ink lines on a sheet of paper. If the ink smears, it is likely brake fluid and you have a leak to trace; if it does not, it is likely assembly oil from the factory. A caliper with a seized piston or a real leak should be replaced; see our brake calipers.

Pulsation: it is usually thickness variation, not a warped rotor

A pedal that pulses or a steering wheel that shakes under braking is usually blamed on "warped rotors." Wagner explains what is really happening. Lateral runout, the side-to-side wobble of a rotor as it turns, lets the pad brush one spot of the rotor on every revolution. Over thousands of miles that contact creates disc thickness variation (DTV): semi-metallic pads wear the high spots thinner, while ceramic pads can deposit material and make spots thicker. As those uneven spots pass through the caliper, the pistons move in and out and you feel it in the pedal.

Wagner notes that most vehicles have a lateral runout specification of two thousandths of an inch or less, and that the most common cause of runout is rust on the hub face that keeps the rotor from seating flat. For the G90, use the exact runout and minimum thickness values in the factory service manual.

The Genesis bulletin lays out the correct process:

1. Clean all rust and contamination before measuring. Measure rotor thickness at 8 points, every 45 degrees, about 5-10 mm (0.2-0.4 in) inboard of the outer edge, before and after any machining.
2. If you resurface, Genesis recommends an on-car brake lathe.
3. After installation, check runout with a dial indicator at the same distance from the edge.
4. Tighten lug nuts in a star pattern to the shop manual torque. The bulletin says this reduces runout.

If a rotor is below minimum thickness or cannot be machined true, replace it. New brake rotors on a clean hub, torqued correctly, fix most pulsation complaints for good.

The fix: parts and procedure for a quiet G90

For front pads, a ceramic compound is a good match for a luxury sedan that is driven for comfort. We carry 2017-2019 Genesis G90 front ceramic brake pads, and you can browse more ceramic brake pads if you want a different option.

After new pads or rotors, burnish them. The Genesis bulletin procedure is to accelerate to 50 mph, brake with moderate force to 10 mph (roughly 6 seconds), and repeat 10 times with as little cooling time as possible. Skipping this step is a common cause of noise and uneven pad deposits on a fresh brake job.

Rear brakes and the electronic parking brake

The rear calipers on the G90 carry the EPB motor, so you cannot simply push the piston back with a C-clamp. The bulletin says to put the system in Brake Pad Change Mode with a scan tool to release the rear calipers, disconnect the EPB actuator before removing the caliper, and retract the piston by rotating it. After reassembly, the EPB is applied and released three times, and an Assembly Check function is run. That check is also required after replacing rear pads, a caliper, the EPB actuator or the EPB control unit.

How hard is this job? Front pads and rotors are a moderate driveway job with a torque wrench and a dial indicator. The rears are only a DIY job if you have a scan tool that supports the Genesis EPB service functions. Brake fluid should be the DOT 3 or DOT 4 fluid specified for your car, and when bleeding, the bulletin says to keep the reservoir above halfway between MIN and MAX so air is not drawn in.

Frequently Asked Questions

Why do my G90 brakes squeal after new pads?

The usual causes are reused shims, reused or missing retainers and springs, grease on the pad backing plate, rust left on the caliper contact points, or pads that were never burnished. The Genesis bulletin says to use new hardware with new pads and to follow its 10-stop burnish procedure.

Are my G90 rotors warped if the pedal pulses?

Usually not. Pulsation is almost always disc thickness variation caused by lateral runout, most often from rust on the hub face. Measure thickness at several points and check runout with a dial indicator before deciding to machine or replace.

Can I replace the rear pads on a G90 without a scan tool?

Not properly. The rear calipers have an electronic parking brake, and Genesis specifies Brake Pad Change Mode to release them and an Assembly Check afterward. Forcing the piston back can damage the actuator.

Should I replace rotors every time I replace pads?

Not always. If the rotors are above minimum thickness, within runout spec and free of deep scoring, they can be reused or machined. If you have grinding or pulsation, new rotors are usually the better value.

What brake fluid does the G90 use?

Genesis says to use the DOT 3 or DOT 4 fluid specified in the vehicle's shop manual. Check the reservoir cap and manual for your car, and never reuse drained fluid.

Sources

1. Genesis TSB 21-BR-002HG, Brake Service Best Practice Recommendations (NHTSA) - rotor measurement, burnishing, pin lubrication, shims and retainers, EPB service, fluid handling
2. 2018 Genesis G90 Owner's Manual - disc brake wear indicator, Electronic Parking Brake, Auto Hold
3. Wagner Brake - Brake System Noise - vibration as the source of noise, hardware and hub corrosion
4. Wagner Brake - Brake Pedal Pulsation and Disc Thickness Variation - lateral runout, DTV and hub rust
5. Bendix - Brake Noise In-Depth: Causes and Prevention - rotor hot spots, torque variation, shims
6. AAA Oregon - 2017 Genesis G90 3.3T Premium review - 3.3T V6 output