2014-2020 Acura RLX Brake Job Guide: Symptoms, Costs and the Right Parts

By Core Brake Parts Tech Team — Circleville, OH warehouse

A brake job on a 2014-2020 Acura RLX means four-wheel disc brakes: vented rotors up front, solid rotors in back, and an electric parking brake that works through the rear calipers. Front pads usually wear out first, but the rear axle needs the parking brake put into its service position before the pistons will retract, so it is not a simple clamp-and-push job. Which rotor you buy depends on whether you have the front-drive RLX P-AWS or the RLX Sport Hybrid SH-AWD, because the front rotor size differs.

How the RLX Brake System Is Built

Acura's own specification sheets list the same basic layout from 2014 through 2020: 4-wheel disc brakes with ABS, Electronic Brake Distribution (EBD), Brake Assist, and an electric parking brake with automatic brake hold. What changes between trims is the front rotor size.

That size difference is the single most important thing to get right when ordering. A 12.3-inch rotor will not fit a Sport Hybrid front, and a 13.0-inch rotor will not fit a P-AWS car, even though the rear rotors share a size. The Sport Hybrid also carries roughly 400 more pounds and uses electric motors to help slow the car, so its pads and rotors see a different wear pattern than the gas-only model. Match parts to your trim, not just the year.

Acura's owner information for the RLX describes a vacuum power assist behind the pedal, Brake Assist that adds stopping force in a panic stop, and ABS that pulses the brakes to prevent lockup. None of those normally need service during a pad and rotor job, but they explain some of the pedal feel you will notice: a pulsing pedal and motor noise during a hard stop is ABS doing its job, not a fault.

Symptoms That Your RLX Needs Brakes

• High-pitched squeal on light braking. Most pads carry a metal wear tab that scrapes the rotor when the friction material gets thin. This is the early warning; do not wait for grinding.
• Grinding or growling. Metal backing plate on rotor. At this point the rotors are almost always damaged and need replacing along with the pads.
• Steering wheel shake when braking from highway speed. Usually uneven pad deposits or rotor thickness variation on the front rotors, which carry most of the braking load on this heavy sedan.
• Longer stops or a softer pedal. Worn pads, glazed friction material, or old moisture-laden fluid. A pedal that sinks slowly while held needs a hydraulic inspection before any parts go on.
• Brake fluid level dropping. As pads wear, caliper pistons move out and the reservoir level falls. A low reservoir with no visible leak usually means worn pads; a low reservoir with wetness at a wheel means a leak that has to be fixed first.
• Parking brake warnings. An electric parking brake fault message after rear work typically points to a caliper motor connector that was not reseated or a service procedure that was skipped.

Front vs Rear: What Wears and in What Order

Front brakes do most of the work on any front-heavy sedan, and the RLX is no exception, so front pads are normally the first service. Rear pads on this car tend to last longer, but they are not immune: automatic brake hold and the electric parking brake both use the rear brakes, and a car that spends its life in stop-and-go traffic puts regular clamping load on them.

On the Sport Hybrid, the electric motors recover energy when you lift off and during light braking, so the friction brakes are used less in gentle city driving. That can stretch pad life, but it also means rotors can develop surface rust or uneven deposits from light use. If a Sport Hybrid shudders with plenty of pad left, rotor condition is the first thing to check.

Inspect all four corners at every tire rotation. Measure both the inner and outer pads, because a sticking caliper slide pin often wears the inner pad much faster than the outer one you can see through the wheel.

The Fix: Which Parts to Replace Together

For a proper RLX brake job, think in terms of one axle at a time:

• Pads. Always replace both sides of an axle. Ceramic brake pads are the usual choice for a luxury sedan like the RLX because they run quiet and produce light-colored dust. Browse all brake pads to compare compounds.
• Rotors. If the rotors are grooved, below minimum thickness, or cause shudder, replace them in pairs. Order the correct front size for your trim (12.3 in P-AWS, 13.0 in Sport Hybrid). See our brake rotors.
• Hardware. New abutment clips and fresh brake grease on the slide pins prevent noise and uneven wear. A brake hardware kit is cheap insurance.
• Calipers, only when needed. A seized slide pin, a torn piston boot, or a caliper that drags after the job means the caliper should be replaced, in axle pairs for even braking. See brake calipers.
• Fluid. Acura's maintenance information for the RLX says to replace the brake fluid every 3 years, independent of the Maintenance Minder. If you are near that mark, do the flush with the brake job, using the fluid type printed on your reservoir cap.

If you would rather buy everything matched at once, our brake parts catalog includes pad and rotor kits sorted by vehicle.

How Hard Is the Job?

Front axle: a straightforward pad and rotor job for anyone with a floor jack, jack stands, a torque wrench, and basic sockets. Remove the caliper, hang it so the hose is not stretched, remove the bracket if the rotor is being replaced, clean rust off the hub face so the new rotor sits flat, and reassemble. Tighten wheel and caliper fasteners to the values in the factory service manual rather than by feel.

Rear axle: harder, because of the electric parking brake. The rear caliper pistons are driven by motors when the parking brake applies, and they cannot simply be pushed back with a C-clamp while the system is in its normal state. The rear brakes have to be put into a service or maintenance mode, normally with a scan tool that supports Acura electric parking brake functions, before the pistons are retracted. After the new pads are installed, the system is taken out of service mode and cycled so the pads seat against the rotor. Skipping this step is the most common way DIY rear brake jobs on electric-parking-brake Acuras end in a warning light.

A few practical notes for the rear:

• Release the parking brake before lifting the car, then chock the front wheels.
• Do not unplug the parking brake motor connector with the power mode on.
• Before lowering the car, confirm the parking brake applies and releases on both sides.

Sport Hybrid: the SH-AWD system has high-voltage components and hybrid-specific service steps. The pad and rotor swap itself is similar, but if you are not familiar with hybrid service procedures, the rear axle on this trim is a good job to leave to a shop with the right tool.

What Drives the Cost of an RLX Brake Job

Cost depends on scope more than anything else. Pads alone on one axle is the smallest job. Pads and rotors on one axle roughly means buying twice the parts. Doing both axles doubles it again, and the rear axle adds labor because of the electric parking brake service procedure. Calipers or a fluid flush add parts and time. The Sport Hybrid's larger front rotors cost more than the P-AWS rotors, and shops typically charge more for the rear of any car with an electric parking brake because it needs a scan tool.

The cheapest brake job is the one you catch at the squeal. Once the pads grind into the rotors, a pads-only job becomes pads and rotors, and a damaged caliper piston can add a caliper.

Break In the New Pads

New pads and rotors need a bedding procedure to lay down an even film of friction material on the rotor face. Skipping it is a common cause of early shudder complaints. Follow the specific procedure from your pad manufacturer: in general it means a series of moderate stops from speed without coming to a full stop, followed by a cool-down drive with light braking. Avoid holding the brakes clamped at a standstill until the pads have cooled after bedding.

Frequently Asked Questions

Are the front brakes the same on every 2014-2020 RLX?

No. Acura lists 12.3-inch vented front rotors on the RLX P-AWS and 13.0-inch vented front rotors on the RLX Sport Hybrid SH-AWD. Rear rotors are 12.2-inch solid discs on both.

Can I push the rear pistons back with a C-clamp?

Not with the electric parking brake in its normal state. The rear brakes must be put into service mode first, normally with a scan tool that supports Acura electric parking brake functions, and taken out of service mode after the job.

Do I have to replace rotors every time I replace pads?

No. If the rotors are smooth, above minimum thickness, and do not cause shudder, new pads can go on the existing rotors. Grooved, scored, or shuddering rotors should be replaced in pairs.

How often should RLX brake fluid be changed?

Acura's RLX maintenance information says to replace the brake fluid every 3 years, independent of the Maintenance Minder messages.

Why does my Sport Hybrid shudder even though the pads are not worn?

The hybrid system handles much of the gentle braking with its electric motors, so the friction brakes can go long stretches with little use. Rotors can pick up surface rust or uneven pad deposits. Inspect and, if needed, replace the rotors and bed in the pads.

Which pad type is best for an RLX?

For daily driving, a quality ceramic pad matches the quiet, low-dust character the car shipped with. Semi-metallic pads bite harder when hot but typically make more dust and noise.

Sources

1. Acura News: 2014 Acura RLX Specifications - 12.3 in vented front / 12.2 in solid rear (P-AWS), 13.0 in front on Sport Hybrid, ABS, EBD, Brake Assist, electric parking brake with brake hold
2. Acura News: 2020 Acura RLX Specifications and Features - same rotor sizes through 2020, curb weights by trim
3. Acura Owners: 2019 RLX Braking - disc brakes at all four wheels, vacuum power assist, Brake Assist, ABS behavior, electric parking brake operation
4. Acura Owners: 2019 RLX Maintenance Minder - replace brake fluid every 3 years independent of the Maintenance Minder
5. PowerStop: Brake Pad Break-In Procedure - why new pads and rotors are bedded in