2006-2015 Lexus IS250 Parking Brake Problems and Adjustment

By Core Brake Parts Tech Team — Circleville, OH warehouse

When the parking brake on a 2006-2015 Lexus IS250 will not hold the car on a hill, lets the pedal travel too far, or rattles over bumps, the cause is almost always at the rear wheels: worn or out-of-adjustment parking brake shoes inside the rear rotor hats, or cable slack. The fix is to set the shoe clearance first and only then take up cable slack, in that order. Lexus even issued a service bulletin for a parking brake rattle on 2014-2015 IS250 models that comes down to exactly that adjustment.

How the IS250 Parking Brake Works

The IS250 stops on four-wheel disc brakes, but the parking brake does not use the rear disc pads. Instead, each rear rotor has a small drum machined into its center hat, and a pair of parking brake shoes sits inside that drum on the backing plate. This layout is usually called drum-in-hat. Cables run from the driver's control to a lever on the shoes; pulling the cable spreads the shoes against the inside of the rotor hat.

On the 2006-2013 generation, the owner's manual shows two controls. Automatic-transmission cars use a foot pedal to the left of the brake pedal: you fully depress the parking brake pedal with your left foot while holding the service brake with your right, and depressing the pedal again releases it. Manual-transmission cars use a hand lever. The 2014-2015 IS250 is still a mechanical, cable-operated system; Lexus's own bulletin for those years has the technician adjust it at a cable adjusting nut.

Because the parking brake shoes rarely do any stopping, they do not wear the way pads do. What usually goes wrong is slow: the shoes glaze or corrode from disuse, the cable stretches, or the clearance was never reset after the rear rotors were replaced.

Common IS250 Parking Brake Problems and Symptoms

The owner's manual is clear on two of these. The brake system warning light also comes on when the parking brake is not released, and if it goes out once the brake is fully released, the system is operating normally. If it stays on, Lexus lists low brake fluid and a brake booster malfunction as the other causes, and says to stop and have it checked. The manual also warns that driving with the parking brake set overheats brake components and increases wear.

Lexus's routine inspection list includes the parking brake: it should move smoothly and hold the vehicle securely on an incline. That is a simple test any owner can do on a safe, gentle slope with a foot ready on the service brake.

The 2014-2015 IS250 Rattle Bulletin

Lexus Technical Service Bulletin L-SB-0005-16 (January 20, 2016) covers 2014-2015 IS250 and IS350 models, plus 2016 IS200t, IS300 and IS350, that make a rattle-type noise from the rear parking brake assemblies when driving over bumps. The bulletin gives two procedures:

1. Procedure A: adjust the parking brake per the repair manual, making sure the No. 1 wire adjusting nut is completely loose during the adjustment. Lexus explains that this ensures there is no gap between the shoe and the anchor inside the parking brake assembly; a gap causes the rattle. Road test afterward.
2. Procedure B (if the noise remains): remove the parking brake shoes and the shoe lever sub-assembly, clean them and the backing plate, and apply disc brake grease where the parking brake plate contacts the shoe and anchor block sub-assembly. Lexus lists part number 08887-80609 for the grease.

The lesson applies to every IS250 year: if the cable is tightened before the shoes are set, the shoes can be pulled off their anchor or left dragging. Slack out of the cable first, shoes second, cable last.

How to Adjust the Parking Brake Correctly

The factory repair manual has the exact procedure and any clearance or pedal-travel specification for your year; follow it rather than going by feel alone. Brake and Front End, the trade magazine for brake technicians, puts it bluntly: never estimate a parking brake adjustment. The general sequence for a drum-in-hat system like the IS250's is:

1. Chock the front wheels, release the parking brake, and raise and support the rear of the car.
2. Back off the cable adjustment so the shoes are fully relaxed. On 2014-2015 cars that means the No. 1 wire adjusting nut is completely loose, per the bulletin.
3. Remove the rear wheel and find the access hole in the rotor hat. Turn the rotor until the hole lines up with the adjuster.
4. Turn the adjuster wheel with a brake spoon or screwdriver to expand the shoes until the rotor will not turn by hand, then back it off just until the rotor turns freely. A very light, even rub is acceptable; a heavy drag is not.
5. Repeat on the other side, then set cable tension as the repair manual specifies.
6. Apply and release the brake several times, confirm both rear wheels spin freely when released, and test that it holds on an incline.

Two cautions from brake-industry sources. Brake and Front End notes that cable adjustment is meant to take up cable stretch, not to compensate for worn shoes, and that once a cable is shortened to its maximum point, it needs replacing. Wilwood's instructions for its own drum-internal parking brakes add a rule that applies here too: never actuate the parking brake lever with the drum off, because the shoes can spring out of place.

When the Rotors or Shoes Need Replacing

Because the parking brake drum is the inside of the rear rotor hat, the rotor and the parking brake are one job. Whenever the rear rotors come off, inspect the shoes, springs and adjuster, and readjust the shoe clearance on reassembly. A new rotor's hat is a fresh, unworn drum surface, so shoes that held fine on an old, worn hat will sit at a different clearance and need resetting.

• Replace the shoes if the lining is thin, cracked, soaked with grease or brake fluid, or separating from the shoe.
• Replace the rear rotors if the hat's drum surface is scored or heavily rusted, or if the braking surface is below the minimum thickness marked on the rotor.
• Replace springs and adjusters that are rusted or seized. A brake hardware kit is inexpensive insurance while everything is apart.
• Replace a cable that is frayed, kinked, seized in its housing, or already at the end of its adjustment.

For 2006-2008 IS250 owners doing the rear axle, the EBC USR slotted rear brake rotor set for the 2006-2008 IS250 fits that car. Replacement brake shoes and brake rotors for other years are in our catalog. If the front brakes are due at the same time, the Brembo OE front disc brake kit for the 2006-2015 IS250 covers rotors and ceramic pads in one box.

How Hard Is This Job?

An adjustment is a moderate home job: it needs the car safely on stands and the wheels off, but no special tools beyond a brake spoon. Replacing the shoes is harder. It means removing the caliper and rotor, then working return springs and hold-downs on the backing plate, which is fiddly. Take a photo of each side before disassembly and do one side at a time so the other side is a reference. If you open the hydraulic system for any reason, the manual specifies FMVSS No. 116 DOT 3 or SAE J1703 brake fluid, and only newly opened fluid.

If the car still will not hold after a correct adjustment with good shoes, have the cable, equalizer and pedal or lever mechanism inspected, and ask your dealer whether any open service campaign applies to your VIN.

Frequently Asked Questions

Why does my IS250 parking brake not hold on a hill?

Most often the shoes inside the rear rotor hats are too far from the drum surface, either from wear, from never being readjusted after a rotor change, or from glazing. Adjust the shoes first, then take up cable slack. A stretched cable at the end of its adjustment needs replacing.

Does the IS250 parking brake use the rear brake pads?

No. It uses a separate pair of shoes inside each rear rotor's center hat, a design called drum-in-hat. New rear pads do not change parking brake holding power.

How do I release the parking brake on a 2006-2013 IS250 automatic?

Per the owner's manual, depress the parking brake pedal again. It sets and releases with the same pedal. Manual-transmission cars use a hand lever instead.

What is the rattle from the rear of my 2014-2015 IS250 over bumps?

Lexus bulletin L-SB-0005-16 traces it to a gap between the parking brake shoe and its anchor. The fix is a parking brake adjustment with the No. 1 wire adjusting nut fully loose, and if that fails, cleaning and greasing the shoe contact points on the backing plate.

Do I need to adjust the parking brake after replacing rear rotors?

Yes. The parking brake drum is part of the rotor, so a new rotor changes the shoe clearance. Readjust the shoes before setting cable tension, and confirm the wheels spin freely with the brake released.

Sources

1. Lexus TSB L-SB-0005-16, via NHTSA - applicable 2014-2016 IS models, rattle cause, adjusting nut note, Procedures A and B, grease part number
2. 2007 Lexus IS250 Owner's Manual - pedal and lever operation, warning light behavior, inspection checks, brake fluid spec
3. Brake and Front End - Adjusting Parking Brakes - drum-in-hat adjustment method, never estimate, cable stretch and replacement
4. Mitchell 1 - Parking Brake Battle for Lexus - rattle symptom and repair summary
5. Wilwood - How to Adjust the Drum Internal Parking Brake - star wheel adjust-and-back-off method, do not actuate with drum off