2009-2012 Infiniti G37 Brake Noise: Squeal, Grinding and Pulsation Causes

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most 2009-2012 Infiniti G37 brake noise comes down to four things: a normal cold-morning squeak, the pad wear indicator telling you the pads are done, glazed or dusty pads and rotors, or rotor thickness variation that you feel as a pulsing pedal. Infiniti's own brake diagnosis bulletin sorts every noise into one of those buckets, and most of the fixes are pads, rotors and correctly lubricated hardware rather than anything exotic.

Below is how to tell which one you have, what actually causes it on this car, and which parts fix it.

How the G37 Brake System Is Laid Out

Every G37 uses power-assisted vented discs at all four corners, with ABS, Electronic Brakeforce Distribution and Brake Assist. There are two different brake packages, and knowing which one you have matters before you buy parts:

The quick check: look through the front wheel. The sport brake has a noticeably larger rotor and a large multi-piston caliper. Pads and rotors are not interchangeable between the two packages, so confirm your package before ordering. Sport-brake owners can shop the Hawk HPS front brake pad set for the 2009-2012 G37 Sport.

Squeal and Squeak: Normal or Not?

Infiniti's bulletin ITB00-024g (brake noise, judder and pedal feel diagnosis, applied to all Infiniti models) separates squeaks by when they happen:

• Squeak on the first few stops of a cold morning. Infiniti calls this a normal condition that needs no service. Overnight moisture leaves a thin film of surface rust on the rotor, and the pads wipe it off in a few stops.
• Squeak once the brakes are warm. This is a real complaint. The bulletin's answer is original-equipment-type pads installed per the service manual, with the rotors finished properly.
• Loud, continuous squeal with or without the pedal pressed. This is the pad wear indicator, a small metal tab that touches the rotor when the pad is nearly gone. Infiniti describes it as normal brake function that means the pads are worn out and must be replaced.
• Squeal from the rear brakes. The bulletin says this is usually brake dust and dirt packed between the pads and rotors. Clean the pads, backing plates and caliper parts with approved brake cleaning equipment (brake dust should not be inhaled), then lubricate the hardware correctly.

Wagner's technical guidance explains why squeal happens at all: vibration is the main source of brake noise, and it comes from rust, distorted components and worn hardware that no longer holds the pad tightly. Anti-rattle clips and springs lose their tension from heat, guide pins corrode and bind, and rust on the caliper mounting surfaces lets the pad sit crooked. A pad that can vibrate will sing.

Grinding, Groaning and Clunking

Grinding. A metallic grind usually means the pad friction material is gone and the backing plate is cutting into the rotor. Bosch Auto Service also lists a sticking caliper as a grinding cause, because it holds the pad against the rotor all the time. If one wheel is much hotter than the others after a drive, or the car pulls to one side, suspect a stuck caliper. Grinding is not a noise to live with: once metal meets metal, the rotor is usually scored too deeply to resurface, so plan on new brake rotors along with pads.

Groan while stopping. Infiniti attributes this to a glazed rotor surface from heavy or frequent braking. Its fix is new pads plus resurfaced rotors finished with sandpaper. On a G37 that sees spirited driving, this is a common complaint.

Groan as you ease off the brake at a stop. Often called creep groan. Infiniti lists it as normal, with no repair needed.

A single clunk from the front when you touch the brakes. The pads shift in the direction of rotor rotation as they are applied, and it is most noticeable with a light pedal. Infiniti's fix is to make sure the pads and all pad hardware (shims, springs, clips) are installed correctly and the pads fit snugly in the caliper.

A series of clunks and a pedal buzz once after start-up. That is the ABS self-check. Depending on the model it runs on the first brake application or the first time the car reaches about 5 mph. Normal, no service needed.

Pulsation and Judder: The Warped Rotor Myth

A pulsing pedal or shimmying steering wheel under braking is what most people call warped rotors. Infiniti's bulletin describes the real mechanisms:

• Rotor thickness variation. When the two faces of the rotor are not flat and parallel, the pads move in and out as they pass the high and low spots. That motion travels through the caliper pistons into the pedal.
• Rotor runout. If the rotor is not true to the hub, the pads brush one spot on each revolution even with the brakes off. Over time that spot wears more, which creates thickness variation.
• Storage rust. A car that sits lets the area of the rotor not covered by the pads rust. The rusted and clean areas grip differently, which can cause judder even after the rust wears off.
• Lug nut over-torque. Uneven or excessive lug torque, especially from an impact gun, can distort the rotor and hub and increase runout. Always finish lug nuts with a torque wrench to the value in the owner's manual.

Wagner adds rust on the hub contact surface and loose or worn wheel bearings to the list. That is why the hub face should be scraped clean before any new rotor goes on.

The Fix: What to Replace and How to Install It

For noise and pulsation that are not in the normal category, the repair is almost always new brake pads and either resurfaced or new rotors, installed with care. Infiniti's bulletin lists the steps that matter most:

1. Finish the rotors correctly. Infiniti calls rotor finish one of the most important parts of preventing noise, and its dealers use an on-car brake lathe. If you install new rotors instead, clean the hub face first.
2. Index the rotor to the hub. Infiniti's procedure: mount the rotor with all lug nuts tightened to 40 ft-lbs (for the indexing check only), mark rotor and hub, measure runout with a dial indicator 10 mm (0.39 in) in from the rotor edge, then move the rotor one stud position at a time until you find the lowest runout. Compare against the limit in the service manual.
3. Install pads and shims correctly. Lubricate the caliper hardware as the service manual specifies and keep grease off the friction surface. Wagner recommends only a light coat of silicone lubricant on the back of constrained-layer shims, and nothing at all on pads with a bonded rubber insulator.
4. Replace worn hardware. Clips and springs that have lost their tension are a common source of rattles and squeal. A brake hardware kit is inexpensive insurance.
5. Burnish the new pads. Infiniti's procedure: from about 30 mph, make a medium-pressure stop that takes 3 to 5 seconds, drive about one minute at 30 mph to cool, and repeat ten times. Bedding lays an even layer of pad material on the rotor and has a direct effect on noise.

While you are in there, look at the fluid. Infiniti's G37 maintenance schedule lists brake fluid replacement every 30,000 miles or 24 months under standard conditions and every 15,000 miles or 12 months under severe conditions. Use the fluid type printed on the reservoir cap or in the owner's manual.

How Hard Is This Job?

Pads and rotors on a G37 are a reasonable driveway job for someone with a floor jack, jack stands, a torque wrench and basic hand tools. The sport-brake cars use multi-piston calipers, so every piston needs to be pushed back evenly before the thicker new pads go in. Infiniti's pedal-feel guidance also calls for checking that the calipers are correctly installed and sliding freely. If you find a seized piston or a caliper that will not release, a replacement from our brake calipers collection is the fix, and the system must be bled afterward. Indexing rotors with a dial indicator and on-car resurfacing are shop-level tasks; most owners simply install new rotors on a clean hub.

Frequently Asked Questions

Why do my G37 brakes squeak only in the morning?

Overnight moisture leaves a light film of rust on the rotors, and the pads scrub it off in the first few stops. Infiniti classifies this as normal and says no service is needed.

My G37 squeals constantly, even without braking. What is it?

That is almost always the pad wear indicator touching the rotor. It means the pads are at the end of their life. Replace them soon, before the squeal turns into grinding.

Are warped rotors really causing my steering wheel shake?

Usually the cause is thickness variation or runout rather than a literally bent rotor. Uneven lug torque, rust on the hub face and a car left sitting are common starting points. New or resurfaced rotors installed on a clean hub and torqued properly fix it.

Do sport brake and standard brake G37s use the same pads?

No. The sport brake uses 14.0-inch front and 13.8-inch rear rotors with 4-piston front and 2-piston rear calipers, while the standard brake uses 12.6-inch front and 12.1-inch rear rotors. Confirm your package before ordering.

Will new pads alone stop the noise?

Sometimes, but Infiniti's own guidance pairs new pads with properly finished rotors, correct hardware installation and a burnish procedure. Skipping any of those is the most common reason new brakes still squeal.

Sources

1. Infiniti bulletin ITB00-024g (via NHTSA) - brake noise, judder and pedal feel diagnosis, rotor indexing and burnish procedure
2. 2009 Infiniti G37 Sedan specifications - standard and sport brake rotor sizes and 4-piston/2-piston sport calipers
3. Infiniti G37 maintenance schedule: brake fluid - brake fluid replacement intervals
4. Wagner Brake: brake system noise - vibration as the source of noise, hardware, shim lubrication and runout causes
5. Bosch Auto Service: common brake noises - squeal from wear indicators and dust, grinding from a sticking caliper