2001-2006 Lexus LS430 Parking Brake Problems and Adjustment

By Core Brake Parts Tech Team — Circleville, OH warehouse

The 2001-2006 Lexus LS430 uses a foot-operated parking brake that works small drum shoes hidden inside the hat of each rear disc rotor. When it stops holding on a hill, drags, or will not release, the cause is almost always one of four things: shoe clearance out of adjustment, stretched or seized cables, worn or contaminated shoe linings, or a frozen mechanism after cold, wet weather. Lexus lists the correct adjustment as 5 to 7 clicks of pedal travel, and most problems come down to restoring that.

How the LS430 Parking Brake Works

The LS430 has rear disc brakes for normal stopping, but the parking brake is a separate mechanical system. Each rear rotor has a drum machined into the inside of its center hat, and a pair of parking brake shoes sits on the backing plate inside that drum. This layout is usually called drum-in-hat. The Lexus parts catalog lists the shoe for all 2001-2006 LS430 models as part 46530-50020 (superseding 46530-50010), described as a parking brake shoe assembly whose lining contacts the drum wall to stop the wheel turning.

You set it by holding the service brake with your right foot and fully pressing the parking brake pedal with your left foot. You release it by pulling the release lever under the dash. Cables run from the pedal assembly back to each rear wheel, where they spread the shoes against the drum.

The published specifications from the LS430 owner's manual are worth knowing before you diagnose anything:

If your pedal goes well past 7 clicks before it holds, the system needs adjustment or repair. If it holds in fewer than 5 clicks, it is adjusted too tight and the shoes may be dragging.

Common LS430 Parking Brake Problems and Symptoms

Pedal travels too far or the car rolls on a hill

This is the most common complaint. As the shoes wear and the cables stretch, pedal travel grows until the brake no longer holds on an incline. Lexus includes holding the vehicle securely on an incline in its owner inspection checklist for exactly this reason. Count the clicks with firm pressure. More than 7 means the shoe clearance or cable slack needs attention.

Brake warning light stays on

The red brake system warning light also comes on whenever the parking brake is not fully released. If it goes out once the brake is fully released, the system is normal. If the light stays on with the pedal released, the pedal switch may be sticking, the pedal may not be returning fully, or the light is reporting something else it covers: low brake fluid or a booster fault. Check the fluid level before assuming it is the parking brake. A warning buzzer also sounds if you drive above roughly 3 mph with the parking brake set.

Rear drag, heat or a burning smell

Lexus warns that driving with the parking brake set overheats brake parts, hurts braking performance and increases wear. On a drum-in-hat system the same thing happens when the shoes are adjusted too tight or a cable does not fully return. Signs are a hot rear wheel after a drive, a burning smell, or a light scraping sound that follows wheel speed.

Brake will not release in winter

The owner's manual notes that the parking brake can freeze up in snowy conditions and not release. Lexus recommends parking in P without setting the parking brake in those conditions. Water getting into the cable housings is also what eventually leads to rusted, sticking cables.

Weak hold after driving through water

Lexus also cautions that when the brakes are wet, the parking brake may not hold securely. If the car rolls only after a wash or heavy rain, let the brakes dry before judging the adjustment.

What Causes It

• Shoe clearance out of adjustment. Drum-in-hat parking brakes do not self-adjust the way a full drum brake does. Normal lining wear and a new or resurfaced rotor both change the gap.
• Cable stretch. Brake and Front End notes that cable stretch reduces holding force and increases pedal travel over time.
• Corrosion. Rusted equalizers, cable ends and shoe hardware keep the brake from applying or releasing fully.
• Worn pivots. Worn hinge pivots can give normal pedal travel but still fail to hold on a slope.
• Worn or contaminated linings. Linings at the 1.0 mm limit, glazed shoes, or shoes soaked with grease or axle seal oil cannot grip the drum.

How to Adjust the LS430 Parking Brake

The correct order is to set shoe clearance first, then take up cable slack. Adjusting only the cable to make up for shoe wear pulls the shoes unevenly and does not last. Follow the torque values and exact steps in the factory service manual for your year; the outline below is the general method.

1. Safety first. Park on level ground, chock the front wheels, shift to P, and make sure the parking brake is released. Support the car on jack stands, never on the jack alone.
2. Remove the rear wheels and check the rotors. Rotate each rotor by hand. If a rotor will not turn with the brake released, the shoes are too tight or a cable is not returning.
3. Inspect the shoes. Pull the caliper and rotor to see the shoes. Replace them if the lining is at or near the 1.0 mm limit, cracked, glazed, or oil soaked. Look for broken springs and seized adjusters while you are there.
4. Adjust the shoe clearance. With the rotor installed, turn the star-wheel adjuster through the access hole in the rotor hat until the shoes drag and the rotor locks, then back it off until the rotor turns freely. If the service manual gives a number of notches to back off, use exactly that number. Brake and Front End's advice is blunt: never estimate a parking brake adjustment.
5. Do not apply the pedal with a rotor removed. Wilwood gives the same warning for its own drum-in-hat parking brakes: working the lever with the drum off throws the shoes out of position.
6. Take up cable slack. Adjust the cable only enough to bring pedal travel into the 5 to 7 click range at firm pressure.
7. Check for drag. Release the pedal and spin both rear wheels. They must turn freely with no more than a faint rub. Reinstall the wheels and torque the lug nuts to specification.
8. Test on a slope. Confirm the car holds on an incline and the warning light goes out when released.

New shoes need to seat against the drum before they reach full holding power. Follow the bedding procedure in the service manual or the shoe maker's instructions.

Parts to Replace at the Same Time

Because the rear rotor has to come off to reach the parking brake shoes, a parking brake job and a rear brake job overlap. If the rear pads are low or the rotors are scored or thin, do them together and save a second teardown. A resurfaced or new rotor also changes shoe clearance, so readjust the parking brake afterward either way.

• Parking brake shoes and hardware. Replace springs and hold-downs with the shoes. See our brake shoes and brake hardware kits.
• Rear pads. For the LS430 we carry the EBC Redstuff ceramic low-dust rear pad set for daily driving and the EBC Yellowstuff street and track rear pads for owners who drive harder.
• Rotors. If the drum surface inside the hat is badly scored or the braking surface is worn, replace the rotor. Browse brake rotors.
• Cables. Replace any cable that is frayed, kinked or sticking. Freeing a rusted cable with lubricant rarely lasts.

If the front brakes are also due, the Brembo OE front disc brake kit for the 2001-2006 LS430 pairs ceramic pads with UV-coated vented rotors.

How Hard Is the Job?

A simple adjustment is a moderate driveway job for someone who has done rear brakes before: jack stands, a brake adjusting tool or flat screwdriver, and patience. Replacing the shoes is harder. The shoes, springs and hold-downs are fiddly, and the rotor and caliper have to come off. Cable replacement adds work under the car and at the pedal. If you are not comfortable setting the adjuster by feel and verifying no drag, have a shop do it; a parking brake set too tight will cook the rear brakes.

Frequently Asked Questions

How many clicks should the LS430 parking brake take?

Lexus specifies 5 to 7 clicks when the pedal is pressed with 66.1 lbf (294 N). More than that means it needs adjustment or repair.

Does the LS430 have rear drum brakes?

No. It has rear disc brakes for normal stopping. The only drums are small ones built into the hat of each rear rotor, used only for the parking brake.

Why is my brake warning light on even though the parking brake is released?

The same light warns of low brake fluid and a brake booster problem. Check the fluid level first, then check that the pedal returns fully. If the light stays on, stop driving and have the brake system inspected.

Can I fix a parking brake that will not hold by tightening the cable?

Only if shoe clearance is already correct. The right order is to set the shoes at the star wheel first, then take up cable slack. Tightening the cable to cover shoe wear gives a poor, uneven hold.

Should I replace the rear rotors when I do the parking brake shoes?

Replace them if the braking surface or the drum inside the hat is worn, scored or out of specification. Either way, readjust the parking brake after the rotors go back on.

Sources

1. Lexus LS430 Owner's Manual - pedal operation, 5 to 7 click adjustment, 1.0 mm lining limit, warning light, winter and wet-brake cautions
2. Lexus Parts Now - LS430 parking brake shoe - OEM part 46530-50020 for 2001-2006 LS430, drum-wall contact design
3. Brake and Front End - Adjusting Parking Brakes - drum-in-hat star-wheel adjustment, cable stretch, corrosion and pivot wear
4. Wilwood - How to Adjust the Drum Internal Parking Brake - adjust to lock then back off; do not actuate with drum removed