1999-2000 Lexus RX300 Front vs Rear Brakes: What Wears First and What to Replace

By Core Brake Parts Tech Team — Circleville, OH warehouse

On a 1999-2000 Lexus RX300 the front brakes wear first, usually by a wide margin. The front axle does most of the stopping, and it uses larger vented rotors to handle that load, while the rear uses smaller solid rotors plus a separate drum-style parking brake inside each rear rotor hat. Expect to replace front pads more often than rears, but inspect both axles every time the wheels come off.

How the RX300 Brake System Is Laid Out

The first-generation RX300 uses disc brakes at all four corners. The two axles are built differently, and that difference explains why they wear at different rates.

The front rotors are vented because they have to shed more heat. Weight shifts forward every time you brake, which loads the front tires and lets the front brakes do more of the work. The rear brakes are sized for a lighter job, and a solid rotor is enough there.

The rear rotor also serves as the parking brake drum. The center hat of each rear rotor is machined on the inside, and a pair of small parking brake shoes expands against that surface when you set the parking brake. That is why rear brake kits for this vehicle are often sold with a parking brake shoe set included.

What Wears First, and Why

Front pads wear first on almost every RX300. Because the front axle handles most of the braking energy, front pads and rotors see more heat and more material loss per stop. It is common to go through two sets of front pads before the rears need attention, although your own ratio depends on how and where you drive. Heavy stop-and-go city driving, towing a small trailer and long mountain descents all shorten front pad life.

The rear pads last longer, but the rear axle has its own failure modes that have nothing to do with pad thickness:

• Rust on the solid rear rotors. Rear rotors run cooler and see lighter pad contact, so surface rust and lip corrosion build up, especially in salt-belt states.
• Sticking caliper slide pins. A rear caliper that does not release fully wears one pad faster than the other and can overheat the rotor.
• Parking brake shoes. If the parking brake is never used, the shoes and adjuster can seize. If it is out of adjustment or accidentally left partly applied, the shoes wear and drag on the inside of the rotor hat.

So the honest answer is that the fronts wear out, and the rears tend to rust out or seize. Inspect both.

Symptoms and How to Tell Which Axle Is the Problem

Front brake symptoms

• High-pitched squeal from the front wheels while driving that changes when you press the pedal (pad wear indicator).
• Steering wheel shake when braking from highway speed, which points to front rotor thickness variation.
• Pulling to one side under braking, often a sticking front caliper or a collapsed front hose.
• Grinding from the front, which means the pad backing plate is touching the rotor. Stop driving and replace pads and rotors.

Rear brake symptoms

• A pulsing felt in the seat or pedal with no steering wheel shake: often the rear rotors.
• A scraping or dragging noise from the rear at low speed: suspect parking brake shoes, a stuck cable or a seized adjuster.
• One rear wheel noticeably hotter than the other after a drive: a dragging caliper or parking brake.
• A parking brake that will not hold on a hill even with the lever pulled far up: worn or out-of-adjustment shoes.

A quick diagnostic: after a normal drive, compare wheel temperatures with an infrared thermometer or the back of your hand held near (not on) each wheel. The fronts should be warmer than the rears. A single rear wheel that is hotter than a front is almost always a dragging brake.

Recall Worth Checking on 1999 Models

NHTSA campaign 99V012 covered certain RX300s equipped with the optional traction control system. The issue was the distribution of the rear brake tubes: if one of the dual brake lines failed, the vehicle could feel unstable under braking. Dealers installed modified brake tubes as the remedy. Most affected vehicles were repaired long ago, but on a vehicle this old it costs nothing to run the VIN through the NHTSA recall lookup or ask a Lexus dealer to confirm the campaign was completed.

What to Replace, and What to Replace With It

Front brake job

Replace front brake pads in axle sets, and in most cases replace the front brake rotors at the same time. On a vehicle this age the original rotors are usually near their minimum thickness, and fresh rotors cost less than a comeback for pulsation. The 1999-2001 RX300 front pad position is served by OE-validated ceramic formulations, so ceramic brake pads keep the quiet feel and low dust you expect from this vehicle.

If a front caliper is seized, leaking at the piston boot or has a torn slide pin boot, replace calipers in pairs. We carry a front brake caliper pair with brackets for the 1999-2001 RX300, which saves you from reusing corroded brackets. Also replace the brake hardware kit (abutment clips and pins) and inspect the front brake hoses for cracks or bulging.

Rear brake job

Rear pads and rotors are usually done together because rust has already pitted the rotor faces by the time the pads are worn. While the rotors are off, look at the parking brake shoes. If the lining is thin, contaminated with grease or brake fluid, or the springs are rusted, replace the shoe set now. It is the only time the shoes are accessible, and doing it later means taking the rear rotors back off. Look in our brake shoes collection for the parking brake set.

Rear rotors on older RX300s are often rusted to the hub. Penetrating oil and a few firm strikes on the rotor hat usually free them. Back off the parking brake shoe adjuster first, or the rotor will hang up on the shoes.

Fluid

Brake fluid absorbs moisture over time, and on a vehicle this old it has almost certainly been neglected at some point. Flush it with the fluid type printed on the master cylinder reservoir cap whenever you replace calipers or open the hydraulic system, and bleed each corner until clean fluid runs out.

How Hard Is the Job?

Front pads and rotors on the RX300 are a straightforward DIY job for anyone with a floor jack, jack stands, a torque wrench and basic hand tools. The caliper bracket bolts can be tight from age, so a breaker bar helps. Torque every fastener to the values in the factory service manual.

The rear is more involved because of the drum-in-hat parking brake. Rotor removal requires backing off the parking brake adjuster, and replacing shoes means working with small springs and retainers. Take a photo of one side before you take it apart and use the other side as a reference. After the job, adjust the parking brake shoes and follow the shoe maker's break-in procedure so the shoes seat against the drum surface.

Before you order, confirm the year and drive type. Front parts listed for the 1999-2001 RX300 do not automatically carry over to the 2002-2003 model, and some rear kits are listed separately for front-wheel drive and all-wheel drive. If you are not sure, our full brake parts catalog lets you narrow by vehicle.

Frequently Asked Questions

Do I need to replace front and rear brakes on my RX300 at the same time?

No. The axles wear at different rates, so replace each axle when its pads reach the wear limit or its rotors show damage. Always replace pads and rotors in pairs on the same axle.

Does the 1999-2000 RX300 have rear drum brakes?

No. It has rear disc brakes for normal stopping. The only drum surface is inside the rear rotor hat, where small shoes act as the parking brake.

Why do my rear rotors rust so badly when the pads still look thick?

The rear brakes do less work, so the pads do not scrub the rotor faces as hard. Moisture and road salt build rust faster than light braking removes it. Regular firm stops help, but heavily pitted rotors need replacement.

Can I reuse the parking brake shoes when I replace the rear rotors?

Yes, if the lining has plenty of thickness left, is not contaminated with oil or fluid, and the springs and adjuster move freely. If any of those checks fail, replace the shoe set while the rotors are off.

Are ceramic pads right for an RX300?

For normal driving, yes. Ceramic pads give quiet operation and low wheel dust, which suits this vehicle. Consider a semi-metallic pad only if you tow regularly or drive steep grades often.

Sources

1. NHTSA recalls database, 1999 Lexus RX300 - campaign 99V012 rear brake tube distribution on traction-control models and its remedy
2. 1A Auto front brake kit for 1999-2001 Lexus RX300 - front rotor 11.65 in. (296 mm), vented, 1999-2001 fitment
3. 1A Auto rear brake kit with parking shoes for 1999-2003 Lexus RX300 - rear rotor 11.34 in. (288 mm), solid, parking brake shoe set included
4. PartsHawk Akebono ACT707A front pad listing - ceramic front pad fitment for 1999-2001 RX300 and OE-validated ceramic formulation