2006-2018 BMW 335i Parking Brake Problems and Adjustment

By Core Brake Parts Tech Team — Circleville, OH warehouse

The parking brake on a BMW 335i is not part of the rear disc brake at all. It is a small pair of drum brake shoes hidden inside the hat of each rear rotor, pulled by cables from the hand lever. When the lever travels too far, fails to hold on a hill, or drags after you release it, the fix is almost always adjusting or replacing those shoes and cables, and BMW's own procedure says the basic setting must be redone every time the rear rotors or shoes are replaced.

How the 335i Parking Brake Works

Look behind the rear wheel of an E90, E92 or E93 335i and you see a normal caliper and rotor. The parking brake lives inside the rotor. The inner surface of the rotor's center bell (the hat) serves as a small drum, and two brake shoes mounted to the backing plate sit inside it. This layout is known as drum-in-hat, and the shoes work in duo-servo mode: when the cable spreads them, the rotating drum drags one shoe into the other through a floating link, so the drum itself adds clamping force. That self-energizing action is why a small shoe can hold a heavy car on a slope.

Between the shoes is a star-wheel adjusting screw. It sets how close the linings sit to the drum. As the linings wear, or when a new rotor with a fresh drum surface goes on, the gap grows and the lever has to travel further before the shoes touch. The hand lever pulls two Bowden cables, one per wheel, through an adjuster unit under the lever boot.

Because the parking brake shoes only work when the car is stopped, they wear very slowly. Most problems come from adjustment, corrosion and cables, not worn-out linings.

Common Parking Brake Problems and Symptoms

The single most common complaint on these cars is a lever that suddenly needs far more travel right after a rear brake job. BMW lists an excessive actuation stroke of 10 teeth on the lever as a trigger for a full basic adjustment, and new brake discs are on the same list. If a shop swapped rear rotors and never touched the adjusters, the shoes are now sitting well away from a fresh drum surface.

What BMW Says About Adjustment

BMW's repair instructions for the E90 family call for a basic handbrake adjustment in four situations: when the parking brake shoes are replaced, when the brake discs are replaced, when the actuation stroke is excessive (10 teeth), and when the handbrake cables are replaced. The inspection standard is also clear. On the first ratchet click there should be no braking force, and the force at the left and right wheels may differ by no more than 30 percent of the higher value.

The factory sequence, in outline:

1. Unclip the gaiter (boot) around the handbrake lever and fully release the lever.
2. Lock the adjuster unit under the lever so the cables stay slack while you set the shoes.
3. With the rear of the car raised, remove one wheel bolt on each rear wheel and turn the wheel until the adjusting screw is visible through the empty bolt hole.
4. Turn the adjusting screw with a screwdriver until the wheel can no longer be turned.
5. Back the adjusting screw off 8 notches.
6. Reinstall the wheel bolt and tighten it to the factory wheel bolt torque.
7. Unlock the adjuster unit by levering the restraining hook off its stop, which lets the cables take up their own slack.
8. Test the braking force, ideally on a brake test stand.

Two points trip people up. First, forgetting the adjuster unit: if it stays locked, the shoes are set correctly but the lever still feels wrong. Second, turning the star wheel the wrong way. If the wheel never locks up no matter how far you turn, you are backing it off, not tightening it.

When Adjustment Is Not Enough

Adjustment only helps if the shoes and cables are healthy. Replace parts when you find:

• Contaminated linings. Oil or grease on the shoes will not hold, however tight they are set. Find the source, often an axle seal, before fitting new shoes.
• Rust-welded or crumbling shoes. Cars that sit, or that rarely use the parking brake, can grow rust on the drum surface and the shoe faces. Light glaze can be cleaned up; delaminated lining cannot.
• Broken or stretched springs. A loose spring inside the hat causes scraping noises and uneven hold. Hardware kits replace springs and retainers together.
• Seized cables. If a wheel drags with the lever fully down, check that the cable end at the backing plate springs back. Frayed or seized cables are best replaced as a pair.
• A worn drum surface. The drum is part of the rotor. If the hat is badly scored or out of round, replacing the rear rotors renews the drum and the disc surface at once.

Springs and small parts are in our brake hardware kits collection, and replacement rear discs are in brake rotors.

What to Replace Together on the Rear Axle

Since the rotor has to come off to reach the parking brake shoes, it makes sense to plan the rear axle as one job. If the rear pads are near their wear sensor, do them at the same time, along with a new rear pad wear sensor. If you are fitting new rotors, the shoes need the basic adjustment anyway, so inspect them while everything is apart.

For the 2006-2012 E90, E92 and E93 335i we carry EBC Bluestuff NDX rear brake pads for the E9x 335i and the matching EBC Bluestuff NDX front pads for the E9x 335i. For the F30 335i there are EBC Bluestuff NDX rear pads for the F30 335i. Bluestuff NDX is EBC's fast street and trackday compound, so it suits owners who drive these turbo sixes hard. For everyday driving, browse ceramic brake pads.

How Hard Is the Job?

A simple adjustment is an easy driveway job: raise the rear, pull a wheel bolt, turn a star wheel, and reset the cable adjuster under the boot. Budget about an hour if nothing is seized.

Shoe replacement is harder. The caliper and carrier come off, the rotor comes off (often stubborn on older cars), and the shoes, springs and expander have to go back in the right orientation in a tight space. Do one side at a time so the other side is a reference. After new shoes or rotors, bed the shoes in gently so the linings conform to the drum. The job is not finished until the lever holds the car firmly on a slope and each rear wheel spins freely with the lever released.

This work only touches the mechanical parking brake. Nothing in the hydraulic system is opened, so no bleeding is needed unless you also disconnect a caliper hose.

Frequently Asked Questions

Why does my 335i parking brake lever go up so far after new rear rotors?

The parking brake drum is part of the rotor. A new rotor has a fresh, unworn drum surface, and the shoe adjusters were set for the old one. BMW requires a basic parking brake adjustment whenever the brake discs are replaced.

Can I adjust the parking brake without removing the wheels?

Yes. The factory method removes one wheel bolt per side and reaches the adjusting screw through that bolt hole with a screwdriver. The car still needs to be raised so the rear wheels can turn.

How many notches do I back off the adjuster?

BMW's E90 procedure is to tighten the adjusting screw until the wheel will not turn, then back it off 8 notches, before unlocking the cable adjuster unit.

Do the parking brake shoes wear out?

Slowly. They only work when the car is stopped, so lining wear is rarely the problem. Rust, oil contamination, broken springs and seized cables are far more common reasons to replace them.

Is it safe to drive with the parking brake dragging?

No. A dragging shoe heats the rotor hat, glazes the linings and adds heat to the rear disc brake. Release the lever, check that each rear wheel spins freely, and correct the adjustment or cable before driving further.

Sources

1. BMW E90 repair instructions: Adjusting handbrake (page 1) - when basic adjustment is required, 10-tooth stroke limit, first-click and 30 percent inspection criteria, locking the adjuster unit
2. BMW E90 repair instructions: Adjusting handbrake (page 2) - access through the wheel bolt hole, tighten until the wheel locks, back off 8 notches, unlocking the adjuster unit
3. Drum brake device including a parking brake operating in duo servo mode (WO2015101486A2) - drum-in-hat layout and duo-servo self-energizing action
4. EBC Brakes: Bluestuff NDX Super Street and Trackday Brake Pads - intended use of the Bluestuff NDX compound