2008-2009 Lexus IS-F Parking Brake Problems and Adjustment

By Core Brake Parts Tech Team — Circleville, OH warehouse

The 2008-2009 Lexus IS-F does not use its rear Brembo calipers to hold the car when parked. Its parking brake is a small drum brake hidden inside the hat of each rear rotor, applied by a foot pedal and cables. When the pedal travels too far, the car rolls on a slope, or the rear wheels drag, the fix is almost always shoe adjustment, worn or glazed shoes, or a stretched or sticking cable, in that order.

How the IS-F Parking Brake Works

Lexus fitted the IS-F with Brembo brakes built to its own engineering spec: 14.2-inch ventilated, drilled front rotors clamped by six-piston aluminum calipers, and 13.6-inch ventilated, drilled rear rotors with two-piston calipers. Those rear calipers only handle service braking. Parking is handled by a separate set of shoes.

The design is called drum-in-hat. The center section (the hat) of each rear rotor is machined on the inside as a small brake drum. A pair of parking brake shoes sits on the backing plate behind the rotor, and the Lexus parts catalog lists dedicated parking brake shoe assemblies for the IS-F (for example "Shoe Assy, Parking Brake, RH Or Center NO.1", part 46530-30020, later superseded to 46530-30021). When you press the pedal, cables pull a lever that spreads the shoes against the inside of the rotor hat. A star-wheel adjuster between the shoes sets how close they sit to the drum surface.

Because the shoes only work when the car is stopped, they wear very slowly. What changes over time is the clearance between shoe and drum, the condition of the drum surface, and the cables.

Common IS-F Parking Brake Problems and Symptoms

• Pedal goes too far before it holds. The classic complaint. Shoe-to-drum clearance has grown, or the cables have stretched. The car may still hold on flat ground but creep on a steep driveway.
• Car rolls with the brake fully set. Glazed or contaminated shoes, a rusted drum surface inside the hat, or adjustment so loose the shoes barely contact the drum.
• Rear wheel drags or gets hot after driving. Shoes adjusted too tight, a cable that does not fully return, or a seized lever. A hot rear hub with no caliper problem points here.
• Scraping or grinding from the rear at low speed. A broken shoe spring, loose hardware, or rust scale inside the hat.
• BRAKE warning light stays on. The usual causes are a pedal that is not fully released or a low brake fluid level. Check both before assuming a fault.

There are no NHTSA safety recalls for the 2008 IS-F that involve the parking brake or service brakes. The recalls on record cover the passenger air bag inflator, a fuel pressure sensor leak, and wiper arm nuts. That makes parking brake trouble on these cars a wear and maintenance issue, not a known defect.

How to Adjust the Parking Brake on an IS-F

The single most important rule: adjust the shoes first, the cable second. Tightening the cable to cover worn shoe clearance gives a pedal that feels right in the garage but leaves the shoes barely spread, and it uses up cable travel you will need later. Trade guidance for drum-in-hat systems is clear that you should never estimate these adjustments; if the service manual says to back off a set number of notches, use exactly that number.

1. Release the parking brake and chock the front wheels. Raise the rear of the car and support it on stands.
2. Remove the rear wheel. Thread a few lug nuts back on to hold the rotor flat against the hub so the hat stays centered over the shoes.
3. Find the access hole. The rotor hat has an adjusting hole, usually covered by a rubber plug. Rotate the rotor until the star wheel lines up with it.
4. Expand the shoes. With a brake adjusting spoon or small flat screwdriver, turn the star wheel to expand the shoes until the rotor will not turn by hand.
5. Back off to spec. Return the adjuster the number of notches listed in the factory service manual, then confirm the rotor spins freely with no more than light drag.
6. Repeat on the other side, refit the plugs and wheels, and torque the lug nuts to the value in the factory service manual.
7. Check the cable last. Count pedal clicks to full apply. Only if travel is still outside the factory range should you adjust the cable at the pedal assembly adjuster.

If the cable adjuster is already run out to its limit, the cable has stretched past use and should be replaced rather than forced. Do not squirt oil or solvent into a sticky cable housing; it attracts grime or washes dirt deeper into the housing, and the cable will bind again.

When Adjustment Is Not Enough

If the car still rolls after a correct adjustment, pull the rear rotors and look at the parts:

• Glazed or oil-soaked shoes. A leaking rear axle seal or brake fluid from a rear caliper can soak the shoes. Contaminated shoes do not clean up; replace them in pairs and fix the leak.
• Rusted drum surface. A car that sits, or is driven in salt, can build a rust ridge inside the hat. Light rust can be cleaned; a deeply scored hat means new rotors.
• Broken springs or a seized adjuster. Replace the hardware; a star wheel that will not turn cannot hold adjustment.
• Seized lever or cable. If the shoes do not spread when a helper presses the pedal, the problem is upstream at the cable or lever.

Shoes, springs and adjusters for drum-in-hat systems are in our brake shoes and brake hardware kits collections.

What to Service at the Same Time

You must remove the rear caliper and rotor to reach the parking brake shoes, so the parking brake job and a rear brake job share most of the labor. If the rear pads are low or the rotors are near minimum thickness, do them together. While everything is apart, inspect the rear pads, caliper slide hardware and flexible hoses; see our brake hoses if a hose is cracked or swollen.

Many owners doing a parking brake job are also due for front pads, since the front six-piston Brembos do most of the stopping. For 2008-2009 IS-F front pads, we carry the Hawk HPS Street front pad set for spirited street driving, the Hawk Ceramic Street front pad set for low dust and quiet daily use, and the Hawk HP Plus front pad set for owners who also run track days. The Hawk HPX Motorsports pads are a dedicated competition compound. Browse all options in brake pads.

How Hard Is the Job?

A shoe adjustment alone is an easy driveway job: wheels off, plug out, star wheel turned, done quickly per side once you have done one. Replacing the shoes is moderate. You remove the two-piston rear caliper and its bracket, hang the caliper so the hose is not stretched, pull the rotor, and then work the shoe springs and adjuster on the backing plate. The springs are small and the hub is in the way, so photograph the assembly before you take it apart. Cable replacement is the most involved, since it runs from the pedal to both rear wheels under the car. If a rotor is stuck because the shoes have caught on a lip of rust inside the hat, back the star wheel all the way off through the access hole before pulling.

Frequently Asked Questions

Does the 2008-2009 IS-F have an electronic parking brake?

No. It uses a foot-operated pedal that pulls cables to mechanical drum-in-hat shoes in the rear rotors. There is no motor at the caliper and no scan tool is needed to service it.

Why does my IS-F parking brake pedal go almost to the floor?

Usually the shoe-to-drum clearance has grown or the cables have stretched. Adjust the shoes at the star wheel first; adjust the cable only if pedal travel is still out of range afterward.

Can I just tighten the parking brake cable?

You can, but it is the wrong first step. It masks loose shoe adjustment, reduces holding power, and uses up the cable's remaining adjustment. Set the shoes first.

Do I need new rotors when I replace the parking brake shoes?

Not always. The shoes ride on the inside of the rotor hat, so replace the rotor if that surface is deeply scored or rusted, or if the braking surface is below minimum thickness.

Why is the BRAKE light on with the parking brake released?

Check that the pedal is fully returned and check the brake fluid level. Low fluid often means worn pads or a leak and should be diagnosed before driving.

Are there any recalls for the IS-F parking brake?

No. NHTSA recall records for the 2008 IS-F list air bag, fuel system and wiper campaigns, none involving the parking brake or service brakes.

Sources

1. Lexus USA Newsroom - IS F - Brembo brake specs (14.2-inch front six-piston, 13.6-inch rear two-piston) and 2008 model-year introduction
2. Genuine Lexus IS F parking brake shoe listing - IS-F uses dedicated parking brake shoe assemblies (46530-30020, superseded to 46530-30021)
3. Brake and Front End - Adjusting Parking Brakes - drum-in-hat star wheel adjustment through the hat, exact back-off counts, cable stretch and lubrication guidance
4. NHTSA recalls - 2008 Lexus IS F - recall list, none involving parking or service brakes
5. Wilwood - Adjusting an internal drum parking brake - expand the star wheel until the drum locks, then back off until it turns