2014-2020 Infiniti Q50 Brake Caliper Problems and Replacement

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most brake caliper problems on a 2014-2020 Infiniti Q50 come down to a caliper that will not fully release: a sticking piston or seized pad hardware that drags the pad on the rotor, overheats one wheel and wears pads unevenly. The fix is usually a replacement caliper on the affected corner, fresh pads and hardware, a rotor check, and a full brake fluid flush with the fluid Infiniti specifies. Before you buy anything, confirm which caliper your car has, because the Sport and Red Sport 400 models use a different multi-piston setup than the other trims.

How the Q50 Caliper System Works

Every Q50 in this generation uses four-wheel disc brakes with ABS, Electronic Brake force Distribution and Brake Assist. When you press the pedal, the master cylinder pushes brake fluid into the caliper bore, the piston moves out and clamps the pad against the rotor. When you let go, fluid flows back toward the master cylinder and the piston pulls back slightly so the pad can release. Any caliper problem is a failure of one half of that cycle: it either will not apply properly or will not release.

There are two caliper families on this car:

• Sport and Red Sport 400 brakes: fixed multi-piston calipers, four pistons up front and two in the rear, clamping large vented rotors. On the Red Sport 400 the rotors measure 14 inches front and 13 inches rear and the calipers are painted red.
• Other trims: a simpler caliper design with smaller rotors. The parts are not interchangeable with the Sport setup, so a caliper, pad or rotor for one will not fit the other.

The quickest way to tell which you have is to look through the wheel. A large caliper with pistons on both sides of the rotor, often wearing a brand logo or red paint, is the Sport package. If you are unsure, your VIN or the build sheet will settle it before you order.

The rear parking brake on the Q50 is a separate set of small shoes that work inside the rear rotor hat. The 2014 owner's manual describes a foot-operated parking brake pedal and notes the parking brake shoes need a break-in whenever the shoes or rotors are replaced. That matters on a rear brake job, because a rear rotor swap disturbs that parking brake assembly too.

Symptoms of a Bad Caliper on the Q50

A failing caliper usually announces itself on one corner, not all four. Watch for these signs:

• Pulling to one side under braking or even while cruising, because one caliper is clamping harder or longer than its partner.
• One hot wheel. After a drive, one wheel is far hotter than the others, sometimes with a burning smell from that corner.
• Uneven pad wear. One pad on a caliper is much thinner than the other, or one side of the car wears pads far faster than the other.
• A "parking brake on" feel. The car feels like it is fighting itself and fuel economy drops.
• Fluid on the inside of the wheel or a dropping reservoir level, which points to a leaking piston seal.
• Soft or low pedal after a caliper leak or if air has entered the system.

Do not confuse caliper trouble with normal pad wear. Infiniti's owner's manual explains that the Q50's disc pads have audible wear warnings: a high-pitched scraping sound that first appears only when you brake, then becomes constant as the pad wears further. That noise means pads, not necessarily a caliper. The manual also notes that occasional squeak or squeal during light to moderate stops can be normal.

What Causes Q50 Calipers to Stick

Calipers stick for two broad reasons: the pads cannot slide the way they should, or the piston cannot retract into its bore.

• Corroded piston and bore. Brake fluid absorbs moisture over time. Water in the fluid attacks the bore and piston, the seal loses its grip and the piston hangs up. This is the most common cause on cars that have skipped fluid changes.
• Torn dust boot. Once the boot splits, road grit and water reach the piston directly and corrosion follows quickly.
• Seized pad hardware. Pads ride on clips and pins. Rust or dried grease there keeps a pad pressed against the rotor even when the pistons are healthy.
• Problems upstream of the caliper. CARDONE's technical bulletin on sticking pistons points out that a caliper can be blamed for a fault that lives elsewhere. If a new caliper still will not release, open the bleeder: if the piston then backs off, the caliper is fine and residual pressure is the problem. Check for a twisted or restricted rubber brake hose, a kinked metal line, a faulty proportioning valve or master cylinder, or a misadjusted booster pushrod or brake light switch.

That last point saves money. A collapsed flexible hose can hold the caliper applied. If you are replacing a caliper on a Q50 with the original hoses, inspect the hose on that corner and replace it with new brake hoses if it is swollen, cracked or restricts flow.

The Fix: Replacing a Q50 Caliper

Once you have confirmed the caliper itself is at fault, the job on one corner looks like this:

1. Confirm the part: Sport multi-piston or standard caliper, front or rear, left or right. Calipers are side-specific.
2. Safely raise and support the car, remove the wheel, and limit fluid loss from the line before disconnecting it.
3. Remove the line fitting, then the pads and caliper mounting bolts.
4. Inspect the rotor. A sticking caliper often leaves a blued, glazed or worn rotor. Measure it against the minimum thickness marked on the rotor, and replace it if it is below spec or badly scored.
5. Install the new caliper with new sealing washers where used, fresh pads and new hardware. Torque every bolt to the value in the factory service manual.
6. Bleed the system until the fluid runs clear and bubble-free, then pump the pedal before moving the car.
7. Bed in the new pads with a series of moderate stops, and on a rear job, follow the parking brake break-in procedure Infiniti describes.

Replacement calipers are in our brake calipers section, including remanufactured units in the CARDONE collection.

What to Replace at the Same Time

For the Q50, we carry 2014-2020 Infiniti Q50 and Q60 front ceramic brake pads from Power Stop, plus brake rotors and brake hardware kits. Always confirm fitment against your trim, since the Sport brakes take different parts.

Brake Fluid: The Maintenance That Prevents Caliper Failure

The single best way to keep Q50 calipers from sticking is to change the brake fluid on schedule. Infiniti's maintenance schedule for the 2018 Q50 calls for replacing brake fluid every 20,000 miles or 24 months under standard conditions, and every 10,000 miles or 12 months under severe conditions, across all trims. For the 2015 Q50, Infiniti recommends inspecting the brake pads, rotors and calipers every 10,000 miles or 12 months, or every 5,000 miles or 6 months under severe conditions.

The 2014 Q50 owner's manual specifies Genuine NISSAN Super Heavy Duty Brake Fluid or an equivalent DOT 3 fluid, and warns that improper or contaminated fluid can damage the brake system. Check the reservoir cap and the owner's manual for your exact model year before you buy fluid, and never top up with an unknown fluid.

How Hard Is the Job?

Replacing a standard caliper is a moderate job for someone comfortable with basic hand tools, a torque wrench and a proper bleeding procedure. The Sport multi-piston calipers are heavier and carry more pad hardware, but the process is similar. The part that trips people up is bleeding: the Q50 has ABS and electronic brake force distribution, so if air reaches the ABS unit, a shop may need a scan tool to cycle the modulator. If the pedal is not firm after bleeding, do not drive the car; have it checked.

Replacing only one caliper is acceptable when the other side is healthy, but always replace pads across the full axle so both sides grip the same.

Frequently Asked Questions

Should I replace Q50 calipers in pairs?

It is not required if only one caliper has failed and the other releases freely with no leaks. Pads, however, should always be replaced on both sides of the axle so braking stays even. On a high-mileage car where both calipers show torn boots or corrosion, doing the pair saves a second job.

Do Sport and non-Sport Q50 calipers interchange?

No. The Sport and Red Sport 400 brakes use four-piston front and two-piston rear calipers with larger rotors. Parts for one package do not fit the other, so confirm your brake package before ordering calipers, pads or rotors.

Why is one wheel much hotter than the others after a drive?

That is the classic sign of a caliper that is not releasing. It can be a stuck piston, seized pad hardware, or a restricted brake hose holding pressure. Check which one before replacing parts.

Is the scraping noise from my Q50 brakes a caliper problem?

Usually not. Infiniti designed the Q50's pads with audible wear warnings that make a high-pitched scraping sound when the pads need replacing. Inspect pad thickness first.

Has the 2014-2020 Q50 had a brake caliper recall?

The NHTSA recall records we checked for this generation did not list a brake caliper campaign; the recalls covered other systems. Always run your own VIN on nhtsa.gov, since recalls are added over time.

What brake fluid does the Q50 use?

The 2014 owner's manual specifies Genuine NISSAN Super Heavy Duty Brake Fluid or equivalent DOT 3. Confirm against the reservoir cap and manual for your model year.

Sources

1. 2014 INFINITI Q50 Owner's Manual - brake fluid spec, pad wear warning, parking brake pedal and shoe break-in, Brake Assist
2. INFINITI 2018 Q50 Brake Fluid Maintenance Guide - brake fluid replacement intervals
3. INFINITI 2015 Q50 Brake Pads and Rotors Maintenance Guide - caliper, pad and rotor inspection intervals
4. The BRAKE Report: INFINITI Q50 Red Sport - Red Sport rotor sizes and four-piston/two-piston calipers
5. CARDONE ProTech: Sticking Caliper Piston Cause and Solution - residual pressure causes and upstream checks
6. CARDONE: Brake Caliper Function and Common Failures - how a caliper applies and releases
7. NHTSA Recalls: 2016 INFINITI Q50 - recall list with no brake caliper campaigns