2013-2020 Lexus GS350 Front vs Rear Brakes: What Wears First and What to Replace

By Core Brake Parts Tech Team — Circleville, OH warehouse

On a 2013-2020 Lexus GS350, the front brakes almost always wear out first. The front axle does most of the stopping, so front pads and rotors typically need replacing about once for every one to two rear services. The rear brakes are simpler, but they hide one detail that trips up DIYers: an electric parking brake that uses separate shoes inside the rear rotor hat.

How the GS350 Brake System Is Laid Out

The fourth-generation GS350 (2013-2020) uses ventilated disc brakes, with four-piston aluminum calipers up front, according to Lexus Canada's 2016 GS specifications. It was sold in both rear-wheel-drive and all-wheel-drive versions, and F Sport trims were offered as well, so rotor and pad part numbers are not the same across every car. Always match parts to your exact year, drivetrain and trim, or measure the old rotor before ordering.

At the back, the GS350 has a conventional hydraulic disc caliper for everyday braking, plus a separate parking brake. Lexus Tech Tip L-TT-0146-13 confirms that the 2013-2014 GS350 has an electronic rear parking brake, and that it has to be adjusted differently from the mechanical parking brake on the previous-generation GS. Lexus parts catalogs list parking brake shoes (part 46530-30040) for 2013-2020 GS350 models. Those shoes press against a small drum machined into the inside of the rear rotor hat. That design, often called drum-in-hat, sets up much of what follows.

Why the Front Brakes Wear First

When you brake, weight shifts forward. The nose dips, the front tires press harder into the road, and the rear axle gets lighter. Engineers size the brakes to match: the front brakes are bigger and do most of the work. The Motorist Assurance Program puts it at about 70% of braking force going through the front brakes on a typical vehicle. The GS350 is a heavy, powerful sedan with a V6 making over 300 horsepower, so the fronts see real heat, especially on highway stops and hills.

So the normal pattern on a GS350 is front pads and rotors first. The rears last longer, but they are not lifetime parts. Stability control and brake-force distribution also use the rear brakes, so a car driven hard or in hilly country can wear its rears faster than you might expect. The only way to know is to measure both axles.

Symptoms and How to Check Each Axle

Most brake problems show up as sounds or feel before they become a safety issue. Here is what points to which end of the car:

• High-pitched squeal when braking lightly: often the pad wear indicator touching the rotor. Check the pad thickness on both axles.
• Grinding: pad material is gone and metal is contacting the rotor. Stop driving and inspect right away. Rotor replacement is almost certain at this point.
• Steering wheel shake when braking: points to uneven front rotors, since the front rotors connect to the steering.
• Pulsation felt in the seat or pedal, not the wheel: can come from the rear rotors.
• Car pulls to one side: a sticking caliper slide pin or piston, or uneven pad wear on one side.
• Parking brake does not hold, or a rattle from the rear over bumps: worn or badly adjusted parking brake shoes. The Lexus tech tip specifically warns that the wrong adjustment procedure can cause a rattle over bumps.

To check pad life, pull a wheel and look at the pad through the caliper window, or remove the pads. Power Stop considers pads at 3 mm or less to be in the replace-now range. Check the rotor for a deep lip at the outer edge, grooves you can catch a fingernail in, blue heat spots, or cracks. Every rotor has a minimum thickness stamped on it, so measure with a micrometer and replace any rotor at or below that number.

What to Replace, and What to Replace With It

For the front axle, the cleanest job is new rotors and pads together. Power Stop's guidance on replacing pads and rotors at the same time explains why: new pads on worn rotors (or the other way around) can reduce braking performance, cause uneven wear and make the car pull, and shorten the life of the new parts. On a car whose rotors have a lip or have been heat cycled for years, fresh rotors save you a comeback.

Our 2013-2020 Lexus GS350 front brake kit pairs front rotors with ceramic pads and hardware for exactly this job. If you only need pads, browse our ceramic brake pads, and for rotors alone see brake rotors. Ceramic pads suit a luxury sedan like the GS because they run quiet and make less dust than semi-metallic pads.

Things worth replacing or servicing at the same time:

• Hardware and abutment clips: new clips help stop squeal and let the pads slide freely. See our brake hardware kits.
• Caliper slide pins: clean them and apply fresh silicone brake grease. Replace torn boots.
• Brake fluid: use the fluid type shown on the master cylinder reservoir cap and in your owner's manual, and flush it if it is dark or overdue.
• Calipers: only if a piston is seized, leaking or its boot is torn. Replace them in axle pairs. Our brake calipers collection is the place to start.
• Rear parking brake shoes: when you have the rear rotors off, check the shoe lining. It is the best time to replace worn shoes.

How Hard Is the Job?

Front brakes: a straightforward job for a DIYer with a floor jack, jack stands, a torque wrench and basic hand tools. Remove the caliper, remove the caliper bracket if the rotor needs to come off, swap the rotor, clean the hub face so the rotor sits flat, install new pads and hardware, and torque everything to the values in the factory service manual. The four-piston front calipers need all pistons pushed back evenly before new, thicker pads will fit.

Rear brakes: a little more involved because of the parking brake. The rotor can drag on the parking brake shoes as you pull it off. Make sure the parking brake is released, and back off the shoe adjustment if the rotor will not come off. Do not pry hard on the rotor. When you reinstall, the parking brake shoes need to be adjusted using the procedure in the repair manual. Lexus issued its tech tip because the procedure on this generation is different from the older GS, and doing it the old way can leave the parking brake weak or rattling.

Bedding in: new pads and rotors need a proper break-in so an even layer of pad material transfers to the rotor. Power Stop's procedure is 5 moderate-to-firm stops from 40 mph down to 10 mph without coming to a full stop, then 5 moderate stops from 35 mph down to 5 mph, then about 5 minutes of easy driving to let everything cool. Do not sit at a light holding the pedal hard on hot new pads.

Frequently Asked Questions

Do the front or rear brakes wear out first on a Lexus GS350?

The front brakes, almost every time. They handle most of the braking force because weight shifts forward during a stop. Expect to replace front pads more often than rear pads, but inspect the rears at every front brake job.

Does the 2013-2020 GS350 have an electric parking brake?

Yes. Lexus confirms the 2013-2014 GS350 has an electronic rear parking brake, and the same parking brake shoe is listed for 2013-2020 models. The shoes work inside a small drum built into the rear rotor hat.

Should I replace rotors every time I replace GS350 pads?

Not always, but it is usually the better job. If the rotor is at or below its minimum thickness, deeply grooved, warped or heat-spotted, replace it. Fitting new pads on worn rotors can mean noise, pulsation and shorter pad life.

Do all 2013-2020 GS350 models use the same brake parts?

No. Rear-wheel-drive, all-wheel-drive and F Sport cars can use different rotors and pads. Confirm your trim and drivetrain, or match the old part number, before ordering.

Why is my GS350 parking brake rattling after a rear brake job?

The parking brake shoes were likely adjusted the wrong way. Lexus warns that using the older-generation adjustment procedure on this car can cause a rattle over bumps. Readjust using the procedure in the repair manual.

Are ceramic pads a good choice for the GS350?

For daily driving, yes. Ceramic pads are quiet and low-dust, which suits a luxury sedan with large, visible wheels. Browse our brake pads for GS350 options.

Sources

1. Lexus Tech Tip L-TT-0146-13 (NHTSA) - 2013-2014 GS350 electronic rear parking brake, its different adjustment procedure, and the rattle warning
2. Lexus Canada: Lexus Updates the GS Line-Up for 2016 - ventilated disc brakes, four-piston aluminum front calipers, AWD availability, V6 output
3. Genuine Lexus GS350 Parking Brake Shoe - part 46530-30040 fits 2013-2020 GS350; drum-type parking brake shoes
4. Motorist Assurance Program: Which Brakes Go Bad First - front brakes handle about 70% of braking force and wear first
5. Power Stop: Should I Replace Brake Pads and Rotors at the Same Time? - reasons to replace together, 3 mm replace-now pad thickness
6. Power Stop: Brake Pad Break-In Procedure - bedding steps and speeds