2003-2009 Toyota 4Runner Brake Job Guide: Symptoms, Costs and the Right Parts

By Core Brake Parts Tech Team — Circleville, OH warehouse

A full brake job on a 2003-2009 Toyota 4Runner means pads and rotors at both ends, plus a look at the small parking-brake shoes hidden inside the rear rotors. The fronts wear out first on almost every truck, and the single most important step before ordering anything is confirming which of the two front rotor sizes your 4Runner has. Get that right and this is a very approachable driveway job.

How the brakes are laid out on the fourth-generation 4Runner

Every 2003-2009 4Runner uses disc brakes on all four wheels. There are no rear drum service brakes on this generation. What does look like a drum is the parking brake: Toyota's parts catalog describes the parking brake shoe as working within a small drum area at the rear wheels, and that drum surface is machined into the hat (the center section) of the rear rotor. So each rear rotor does two jobs - its outer faces are squeezed by the rear caliper when you brake, and its inner drum surface is what the parking brake shoes grab when you set the pedal.

Up front, Toyota built these trucks with two different front brake packages. Toyota's own catalog lists two front rotors for the 2003-2009 4Runner - part 43512-35322, described as the 16-inch front wheel brake rotor, and part 43512-60151 - and notes that there are two different size rotors for these years, recommending VIN verification. The larger package uses a 338 mm (13.3 inch) front rotor. The rear rotor, by contrast, is shared: Toyota part 42431-60201 fits every 2003-2009 4Runner, V6 or V8, and also the 2007-2010 FJ Cruiser and 2001-2007 Sequoia.

The quickest way to tell the fronts apart without a VIN lookup is to pull a wheel and measure the rotor face edge to edge. A tape measure is enough to separate the two sizes, and it removes all doubt before you spend money.

Symptoms that your 4Runner is due for a brake job

• High-pitched squeal while driving that goes away when you press the pedal. That is usually the pad wear indicator tab touching the rotor. It is a warning, not an emergency, but book the job.
• Grinding or a metal-on-metal growl. The friction material is gone and the backing plate is cutting the rotor. At this point the rotors are almost always scrap.
• Steering-wheel shake or pedal pulsation when stopping from highway speed. A classic sign of front rotor thickness variation, often from heat on a heavy SUV that tows or runs mountain grades.
• Pulling to one side under braking. Points to a sticking caliper piston or seized slide pin on one side, or contaminated pads.
• Parking brake that holds poorly or needs many clicks. The rear shoes are worn, glazed, or out of adjustment - a separate issue from the rear pads.
• Low or spongy pedal, or fluid level dropping. Pad wear lowers the reservoir slightly as caliper pistons extend, but a noticeably low level or soft pedal calls for a leak check before anything else.

What wears, and in what order

A 4Runner is a heavy body-on-frame SUV, and like most trucks it puts most of its stopping work through the front axle. Expect front pads to wear out before the rears, often by a wide margin. Front rotors usually go with the second set of front pads if not the first, especially on trucks that tow, carry roof loads, or live in hilly country.

Rear pads last longer, but the rear rotors have a second wear surface you cannot see from outside: the parking brake drum inside the hat. If someone habitually drives with the parking brake partly applied, or the shoes are out of adjustment, that inner surface can be worn or scored even when the outer braking faces look fine.

With age, the calipers become the next weak point. Pistons that stick, torn dust boots, and dry or seized slide pins all cause one pad to wear much faster than its partner. Uneven wear between the inner and outer pad on the same wheel is the tell.

Front vs rear: how the two jobs differ

Front brakes

The front job is straightforward: remove the wheel, pull the pads, remove the caliper and bracket, then take off the rotor. Hang the caliper from the frame or a wire - never let it dangle from the rubber hose. Clean the bracket where the pad ears ride, fit new abutment clips, and lubricate the pad contact points with a brake-specific grease. Push the pistons back slowly and watch the master cylinder reservoir so it does not overflow. On the larger 338 mm package the rotor is big and heavy, so get a good grip before it breaks free of the hub.

Rear brakes

The rear pads and caliper come off the same way, but before the rotor will slide off you usually have to back off the parking brake shoe adjuster through the access hole, because the shoes can hold the drum surface. Once the rotor is off, inspect the shoes, springs and adjuster. When you reinstall, adjust the shoes so the new rotor turns with only a slight drag, then check parking brake travel. Skipping this step is the most common reason a freshly serviced 4Runner has a weak parking brake.

For both axles, torque the caliper bracket bolts and lug nuts to the values in the factory service manual, and tighten lug nuts in a star pattern.

What to replace together

• Pads and rotors as a set, per axle. Fresh pads on worn or heat-marked rotors rarely bed in properly on a vehicle this heavy. A matched set of brake pads and brake rotors gives you a clean start.
• Hardware. Abutment clips and slide pin boots are inexpensive and are what keep pads from sticking. See our brake hardware kits.
• Calipers, if a piston is sticking. If one side wore much faster, or a boot is torn, replace the caliper rather than fitting new pads to a bad one. We carry replacement brake calipers.
• Parking brake shoes, when the rears are off. They are inexpensive relative to the labor of taking the rear rotors off twice.
• Brake fluid. Brake fluid absorbs moisture over time. A flush at brake-job time is sensible; use the fluid type printed on the master cylinder reservoir cap.

If you tow or run large tires, a truck-oriented pad compound is worth considering because it is designed for heat. For a daily driver, a quality ceramic brake pad keeps dust and noise down.

How hard is it, and what drives the cost

For someone with a floor jack, jack stands, a basic socket set and a torque wrench, the front brakes on a 4Runner are a moderate first-timer job. The rears are a step harder only because of the parking brake adjuster. Plan an afternoon for both axles if you have not done it before.

Cost comes down to a few choices rather than a fixed number:

• Pads only vs pads and rotors. Rotors are the bigger parts expense, and the large front rotors on these trucks are substantial pieces of iron.
• One axle vs both. Doing only the fronts is common and perfectly valid if the rears measure well.
• Shop labor. A shop charges per axle, and the rear parking brake service adds time.
• Extras found on inspection. A seized caliper, a leaking hose, or worn parking brake shoes all add to the bill - better to find them now than after a new pad set wears unevenly.

Buying a complete front or rear pad and rotor kit is usually the simplest way to get parts matched to the correct rotor size. Browse all brake parts for your 4Runner and filter by your year.

Frequently Asked Questions

Does the 2003-2009 4Runner have rear drum brakes?

No. It has rear disc brakes. The small drum inside the rear rotor hat is only for the parking brake shoes.

How do I know which front rotor size my 4Runner has?

Toyota lists two front rotors for these years and recommends checking by VIN. You can also remove a front wheel and measure the rotor diameter; the larger package measures 338 mm (13.3 inches).

Are the rear rotors the same on every 2003-2009 4Runner?

Yes. Toyota uses one rear rotor part for all 2003-2009 4Runners, V6 and V8, and the same part fits the 2007-2010 FJ Cruiser and 2001-2007 Sequoia.

Why won't my rear rotor come off?

The parking brake shoes are usually holding it. Make sure the parking brake is fully released and back off the adjuster through the access hole, then the rotor should slide off.

Should I replace the front and rear brakes at the same time?

Only if both axles need it. The fronts usually wear out first. Measure the rear pads, inspect the rear rotors and parking brake shoes, and replace what is worn.

Why is one front pad worn much more than the other?

That points to a sticking caliper piston or a seized slide pin. Fix or replace the caliper at the same time as the pads, or the new pads will wear the same way.

Sources

1. Genuine Toyota front rotor 43512-35322 - 16-inch front brake rotor fitment for 2003-2009 4Runner
2. Genuine Toyota front rotor 43512-60151 - second front rotor for 2003-2009 4Runner and the two-size VIN note
3. Genuine Toyota rear rotor 42431-60201 - one rear rotor for all 2003-2009 4Runners, FJ Cruiser and Sequoia
4. Genuine Toyota 4Runner parking brake shoes - parking brake shoes working inside a small drum area at the rear wheels
5. Power Stop kit specs for 2003-2009 4Runner with 338 mm front rotors - 13.3 in front and 12.3 in rear rotor diameters and nominal thicknesses