What you need before you start

Replacing rotors on a 2019 Infiniti Q50 requires a jack, jack stands, a socket set, a brake caliper tool (also called a C-clamp), new rotors sized for your Q50, and brake pads if yours are worn. You'll also need a torque wrench set to 72 foot-pounds, which is the specification for Q50 rotor bolts. The job takes two to four hours depending on your experience and whether you're doing all four wheels or just the fronts.

Before you buy parts, confirm whether you have single-piston or dual-piston calipers on your Q50—most 2019 models have single-piston in the rear and dual-piston in the front, but this affects how you'll compress the caliper. Check your owner's manual or a parts diagram to verify your rotor size and thickness. Rotors come in vented (better cooling) and solid varieties; most Q50s use vented rotors on the front.

Work on a level surface with the parking brake set. Wear safety glasses and work gloves. Do not work under a car supported only by a jack—always use jack stands rated for your vehicle's weight (the Q50 weighs roughly 3,600 to 3,800 pounds depending on trim).

Key Takeaways

  • You will need a jack, jack stands, a socket set, a C-clamp, new rotors, a torque wrench, and safety equipment before starting.
  • The front rotors are easier to access than the rear, and most people start there; the rear requires removing the parking brake cable from the caliper bracket.
  • Rotors bolt to the wheel hub with bolts that must be torqued to exactly 72 foot-pounds to prevent vibration and uneven wear.
  • Brake pads should be replaced at the same time as rotors if they are worn below 3/32 inch thickness, since new rotors against old pads causes uneven braking.

Removing the wheel and caliper assembly

Loosen the lug nuts on the wheel while the car is still on the ground—do not remove them yet. Raise the Q50 with the jack under the frame rail (not the plastic trim), then place jack stands under the frame on both sides of the wheel you're working on. Lower the car onto the stands. Now remove the lug nuts and pull the wheel straight toward you.

You will see the brake caliper bolted to a bracket behind the rotor. The caliper has two bolts: one at the top and one at the bottom, usually 17mm or 18mm. Remove both bolts using your socket wrench. The caliper will swing out; do not let it hang by the brake line. Instead, use a wire or bungee cord to tie it to the suspension or frame so the line stays slack.

If you are replacing brake pads at the same time, remove them now from the caliper bracket. They slide out or are held by a pin, depending on your Q50's year and trim. Set them aside if you plan to reuse them, or discard them if they are worn.

Unbolting and removing the old rotor

The rotor is held to the wheel hub by two or three bolts (usually 17mm). These bolts are often tight and may have rust or corrosion. Spray them with penetrating oil and let it soak for a few minutes if they resist. Remove the bolts and set them aside—you will reuse them.

Pull the rotor straight toward you. It may stick slightly to the hub due to rust. If it does not come free easily, tap the back of the rotor gently with a rubber mallet. Do not strike the rotor face itself, as this can crack it. Once the rotor is off, inspect the wheel hub for rust or debris. Wipe it clean with a rag.

Installing the new rotor and torquing bolts

Slide the new rotor onto the wheel hub, aligning the bolt holes. Insert the rotor bolts by hand first to center the rotor, then tighten them in a star pattern (top, bottom, left, right, then any remaining bolt) to avoid warping. This distributes pressure evenly. Once all bolts are hand-tight, use your torque wrench to tighten each bolt to 72 foot-pounds in the same star pattern.

Do not skip the torque wrench step. Bolts that are too loose will cause the rotor to wobble and create vibration when braking. Bolts that are too tight can warp the rotor or strip the threads on the hub. After torquing, spin the rotor by hand to confirm it turns freely without rubbing.

Reinstalling brake pads and the caliper

If you removed the old pads, install new ones into the caliper bracket now. They should slide in smoothly and sit flush against the bracket. If you are reusing old pads, clean the back of each pad with a rag to remove any dust or debris.

Swing the caliper back into position over the rotor and pads. The caliper should fit snugly without forcing. Insert the two caliper bolts and hand-tighten them, then use your socket wrench to tighten them fully. These bolts do not require a torque wrench on most Q50s, but tighten them firmly—they typically need 25 to 30 foot-pounds of force, though your manual will specify.

Reinstalling the wheel and checking your work

Slide the wheel back onto the hub and insert the lug nuts by hand. Tighten them in a star pattern to snug them down, but do not fully tighten yet. Raise the car with the jack and remove the jack stands, then lower the car to the ground. Now tighten the lug nuts fully in the star pattern using your socket wrench. Most Q50s use 80 to 100 foot-pounds for lug nuts, but check your manual.

Repeat this process for the other wheels if you are replacing all four rotors. After finishing all wheels, pump the brake pedal several times while the car is parked to reset the brake pads against the new rotors. The pedal should feel firm and not sink to the floor.

Before driving, test the brakes in a safe, empty area at low speed. The brakes may feel slightly softer or less responsive for the first 100 to 200 miles as the pads bed in to the new rotor surface. Avoid hard braking during this break-in period.

Rear rotor replacement differences

The rear rotors follow the same basic steps as the front, but the rear caliper bracket also holds the parking brake cable. Before removing the caliper, locate the cable where it connects to the bracket and unclip it or remove the bolt holding it. You may need to compress the parking brake lever slightly to release tension on the cable. After removing the caliper bolts and swinging the caliper out of the way, you can proceed with unbolting and replacing the rotor exactly as you did in front.

When reinstalling the rear caliper, reconnect the parking brake cable before tightening the caliper bolts. Make sure the cable is not twisted and sits in its original position on the bracket. Test the parking brake after finishing to confirm it holds the car on a slope.

Frequently Asked Questions

Do I need to replace all four rotors at once?

No. You can replace rotors one wheel at a time or in pairs (front or rear). However, if the rotors are worn unevenly or one side is significantly thinner than the other, replacing both sides at once prevents uneven braking feel. Check rotor thickness with a caliper tool—if one rotor is 0.5mm or more thinner than its opposite, replace both.

What if the rotor bolts won't come loose?

Spray penetrating oil around the bolt heads and let it soak for 15 to 30 minutes. Tap the bolt head gently with a hammer to help break corrosion. Use a socket that fits snugly (not loose) and explore steady pressure rather than jerking. If a bolt still resists, heat it carefully with a heat gun to expand the metal slightly, then try again. Never use a breaker bar on a bolt that is already tight—you risk stripping it.

Can I drive the car when ready after replacing rotors?

Yes, but avoid hard braking for the first 100 to 200 miles. The new pads and rotors need time to bed in, which means the friction surfaces are still conforming to each other. Gentle braking during this period helps them wear evenly. After 200 miles, the brakes will perform at full strength.

How do I know if my brake pads need replacing too?

Brake pads should be replaced if they are thinner than 3/32 inch (about 2.4mm). You can measure them with a ruler or caliper while the wheel is off. If the pads are worn to this thickness or thinner, replace them when you replace the rotors. Worn pads against new rotors causes uneven braking and can damage the new rotors quickly.

What does it mean if the rotor has a lip or ridge on the edge?

A lip or ridge on the outer edge of the rotor means it has worn unevenly, usually because the pads were worn or the caliper was sticking. This is normal wear and does not mean the rotor is defective. The new rotor will not have this ridge, and it will wear evenly if the pads and caliper are in good condition.