2017-2020 Genesis G80 Brake Noise: Squeal, Grinding and Pulsation Causes

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most brake noise on a 2017-2020 Genesis G80 comes down to three things: a pad wear indicator telling you the pads are done (high squeal), worn-through friction material cutting into the rotor (grinding), or rotor thickness variation you feel as a pulse in the pedal. Genesis published a brake service bulletin for this car that spells out how the brakes should be serviced to stay quiet, and most repeat-noise complaints trace back to one of its steps being skipped.

How the G80 brake system is laid out

The G80 uses disc brakes at all four corners with an Electronic Parking Brake (EPB) at the rear calipers. The Genesis quick reference guide describes applying the EPB by pulling its switch and releasing it by pressing the switch with the brake pedal down, and it lists an Auto Hold feature that keeps the brakes applied at a stop until you press the accelerator.

Genesis Technical Service Bulletin 21-BR-002HG, "Brake Service Best Practice Recommendations" (March 2021), covers all 2017 and 2018 G80 (DH) models. It includes separate procedures for floating-type and fixed-type front calipers, so depending on the version of the car, the front brake is either a sliding single-side caliper or a fixed caliper with pistons on both sides. That matters for noise, because the two types are cleaned and lubricated differently. The same DH-generation car continued through 2020, so the bulletin is a sound guide for the later years too, but the bulletin itself names only 2017-2018.

Squeal: what it means and how to track it down

A high, thin squeal on light braking that goes away when you press harder is the classic sign of a pad wear indicator. The indicator is a small metal tab on the pad that contacts the rotor once the friction material is low. The Genesis bulletin notes that the pad with the wear indicator installs in the inner position, so you usually will not see it without pulling the wheel. If you hear this sound, measure pad thickness at all four corners. It is a warning, not an emergency, but the next stage is grinding.

If the pads still have plenty of material and the car squeals, look at how the last brake job was done. The bulletin lists several practices that directly affect noise:

• Shims reused on new pads. Genesis says never reuse shims on new pads. Worn or mismatched insulators are a common cause of squeal right after a pad swap.
• Grease on the pad backing plate. The bulletin warns that grease on the backing plate can trap debris and increase the chance of noise or dragging, unless the shop manual calls for it.
• Old retainers and springs. Genesis calls for using the retainers and pad springs supplied with the new pads, and discarding damaged ones.
• Corroded abutments. The caliper contact surfaces should be wire-brushed clean and given a light coat of copper anti-seize brake lube to prevent further corrosion.
• Glazed pads. Pads that were never bedded in, or were overheated, can go hard and shiny and squeal. The bulletin includes a burnishing procedure for this reason (see below).

Grinding: stop driving on it

A low metallic grind or growl, especially one you can feel in the pedal, usually means the pad friction is gone and the steel backing plate is contacting the rotor. At that point the rotor is being cut, and the pads and rotors on that axle both need replacing. Other grinding causes are a stone caught between the rotor and the splash shield, or a pad seized in its bracket so it drags constantly.

Drag is worth checking on the floating-caliper versions. The bulletin warns that over-lubricating the caliper slide pins can trap air at the end of the pin and create an "air spring" that makes the caliper and pad drag on the rotor. A dragging corner runs hot, wears its pad fast and can glaze or groove the rotor. Genesis specifies silicone paste on the slide pins for floating calipers. On fixed calipers it says to clean the guide pins without abrasives and not to grease them unless the shop manual says to.

Pulsation: usually thickness variation, not a warped rotor

A pedal that pulses or a steering wheel that shakes under braking is almost always disc thickness variation: parts of the rotor face are thicker than others, so the pads are pushed in and out as the rotor turns. Power Stop's technical explanation lists the usual causes as uneven clamping force, improper rotor installation, misaligned calipers, irregular friction patterns, and rust or dirt buildup.

The Genesis bulletin's rotor procedure lines up with that. It calls for:

1. Measuring rotor thickness at 8 points around the rotor (every 45 degrees), 5-10 mm (0.2-0.4 in) in from the outer edge, before and after machining, and comparing it to the minimum thickness in the shop manual.
2. Cleaning off contamination and corrosion before measuring so the reading is accurate.
3. Checking runout with a dial indicator at the same distance in from the edge after the rotor and caliper are reinstalled.
4. Tightening the lug nuts in a star pattern to the shop manual torque, which Genesis says reduces runout. Running wheels on unevenly with an impact gun is a common way to create pulsation a few thousand miles after a brake job.
5. Using an on-car brake lathe when machining is chosen.

If your rotors are near minimum thickness, replacement is the better call than machining. New rotors paired with new pads also give you a clean start for bedding.

The fix and which parts to use

For squeal from worn pads, replace the pads on both sides of the axle along with new hardware. Our 2017-2020 Genesis G80 front ceramic brake pads from Bosch are listed for this car; you can also browse our Bosch brake parts and ceramic brake pads. Confirm fitment by trim and caliper type before ordering, since the front brake differs between versions.

For grinding or pulsation, replace pads and rotors together. See our brake rotors and, if your old clips and retainers are rusted or bent, a brake hardware kit.

After installing new pads and rotors, burnish them the way Genesis describes: accelerate to 50 mph, brake with moderate force down to 10 mph (roughly 6 seconds), and repeat 10 times with as little cooling time as possible. Do this on a safe, empty road.

What to do at the same time, and how hard the job is

The front brakes are a standard pad and rotor job for someone with basic tools, a torque wrench and jack stands. The rears are harder because of the EPB. The bulletin says the Brake Pad Change Mode must be run to release the rear calipers before a caliper is removed, the EPB actuator is disconnected before the caliper comes off the bracket, and the piston is retracted by rotating it. After reassembly, Genesis has the EPB applied and released three times in that mode and then runs an Assembly Check function. That requires a capable scan tool. Without one, leave the rear brakes to a shop.

While the wheels are off:

• Check each caliper for leaks. The bulletin notes that some fluid around a caliper piston can be assembly oil, and gives an ink-smear test: brake fluid makes ink run, assembly oil does not.
• If fluid is leaking at the banjo bolt, replace the copper sealing washers.
• Inspect the hoses, and never let the caliper hang by its hose.
• If you bleed the brakes, keep the reservoir above the halfway point between MIN and MAX so no air gets in, and tighten the bleeder to the 5.1-9.4 lb-ft Genesis lists.

One more item for 2017-2020 G80 owners: NHTSA recall 21V-160 covers an ABS module that can short internally and cause an engine compartment fire. The remedy is a replacement ABS module fuse installed free by the dealer. It does not cause brake noise, but check your VIN to be sure it has been done.

Frequently Asked Questions

Why do my G80 brakes squeal right after new pads were installed?

The most common reasons are reused shims, grease on the pad backing plates, corroded caliper abutments, or pads that were never bedded in. The Genesis service bulletin addresses each of these, and running the burnishing procedure often clears up noise from fresh pads.

Are my G80 rotors warped if the pedal pulses?

Almost always it is disc thickness variation rather than a bent rotor. Uneven lug nut torque, rust on the hub face and uneven pad deposits are the usual causes. Measure rotor thickness at several points and check runout; replace the rotors if they are near minimum thickness.

Can I replace the rear pads on a G80 without a scan tool?

Not properly. The rear calipers have an electronic parking brake, and the Genesis procedure uses a Brake Pad Change Mode to release them and an Assembly Check afterward. Forcing the piston back without releasing the EPB can damage the actuator.

What brake fluid does a Genesis G80 use?

Genesis specifies genuine DOT 3 or DOT 4 as listed in the shop manual for your specific car, and the maintenance schedule calls for inspecting the fluid every 30,000 miles. Check the reservoir cap or your owner's manual for the exact spec.

Should I replace pads and rotors together?

If the rotors are grooved, below minimum thickness or causing pulsation, yes. If they measure in spec and are smooth, new pads alone can be fine, but new rotors with new pads give the best chance at quiet, pulse-free braking.

Sources

1. Genesis TSB 21-BR-002HG, Brake Service Best Practice Recommendations (NHTSA) - rotor measurement, burnishing, shim and lubrication practice, EPB service steps, fluid and bleeder torque
2. 2017 Genesis G80 Quick Reference Guide (Genesis Owners) - maintenance inspection intervals, EPB and Auto Hold operation
3. NHTSA recalls for the Genesis G80 - recall 21V-160 and its ABS module fuse remedy
4. Power Stop: Why Do I Have a Pulsing Brake Pedal? - causes of disc thickness variation and pedal pulsation