1996-2002 BMW Z3 Parking Brake Problems and Adjustment

By Core Brake Parts Tech Team — Circleville, OH warehouse

The parking brake on every 1996-2002 BMW Z3 is a small drum brake hidden inside each rear rotor, worked by two cables from the center-console lever. When it stops holding, the cause is almost always one of four things: shoes that were never adjusted, a seized adjuster screw, stretched or corroded cables, or worn and broken shoes. Most of it can be fixed in about an hour with the wheels still on the car.

How the Z3 Parking Brake Works

The Z3 uses a drum-in-hat design. Its rear disc brakes handle normal stopping, but the parking brake is a separate set of shoes mounted to the backing plate behind each rear rotor. The inside of the rotor's hub section acts as the drum. When you pull the lever, two cables (one per wheel) pull on an expander at the bottom of the shoes, which spreads them against the inside of the rotor hat.

At the top of each pair of shoes sits a threaded adjuster with a toothed wheel. That adjuster sets how close the shoes rest to the drum surface. The cable nuts at the lever only take up slack in the cables. That split matters: the shoes are adjusted at the wheel first, and the cables are adjusted at the lever second. Tightening only the cable nuts to cover for shoes that are backed off too far is the most common reason a Z3 parking brake feels weak or uneven.

Because the shoes rarely do any stopping, they last a long time. The trouble on a car this old comes from parts that sit unused: adjusters that seize, cables that corrode inside their sheaths, and retaining hardware that rusts.

Symptoms and How to Diagnose Them

The quickest check is to count clicks. Pelican Parts' Z3 guide says that if the lever makes 10 clicks or more before it stops, the parking brake needs adjusting. A healthy, freshly adjusted system is set so the wheels lock within about six notches of lever travel.

Common Causes on the Z3

Adjuster screw seized

The adjuster lives inside the rotor hat, where brake dust and moisture collect. BimmerWorld, which sells the OEM adjusting screw for the Z3 (BMW part number 34-41-6-851-438), notes that these screws often jam with brake dust or corrosion and will no longer turn. If the star wheel will not move through the lug hole, the rotor has to come off so the adjuster can be cleaned or replaced.

Cables corroded or stretched

The two cables run from the lever through steel sleeves in the floor to the rear wheels. ZRoadster's Z3 cable replacement write-up explains that once the outer sheath splits, water gets in, the inner wire corrodes and it can eventually snap. A corroded cable also binds, so the brake may apply but not fully release.

Shoes worn, contaminated or broken

Pelican Parts documents two failure modes on Z3 shoes: the lining can come off the shoe and cause a grinding noise, and the hole in the backing plate that holds a shoe retaining clip can rust out. When that happens, the clip pulls through and the shoe rubs on the rotor while driving. That repair needs a new backing plate, shoes, hardware and rotor. BimmerWorld's shoe listing puts it simply: if the parking brake still will not hold after a proper adjustment, the shoes are likely due.

Never adjusted after brake work

Any time the rear rotors are replaced, the parking brake shoes should be readjusted. A new rotor has a fresh drum surface, and the shoes are usually backed off to get the old rotor off. Skipping this step leaves a long, soft lever.

How to Adjust the Z3 Parking Brake

This is the procedure Pelican Parts publishes for the 1996-2002 Z3. It takes about an hour, and the wheels stay on the car.

1. With the car on the ground, remove one wheel bolt from each rear wheel. Then lift and support the rear of the car safely. Leave the transmission in neutral and the lever released.
2. Inside the car, pull the rear of the lever trim up and away from the console to expose the two cable adjusting nuts in front of the lever. Loosen both until they are at the end of the studs, so the cables are fully slack.
3. Rotate a rear wheel until the adjuster's toothed wheel shows through the empty bolt hole. A small flashlight helps.
4. With a flathead screwdriver, lever the adjuster to expand the shoes until the wheel cannot be turned. Then back it off. Pelican's article quotes BMW's instruction as 18 catches for the Z3, and 8 catches on M3-type rear brakes. Other published guides use different counts, so confirm the figure for your exact model in the factory service manual. The wheel must spin freely with no shoe drag when you are done. The screwdriver direction is opposite on the left and right sides, so watch which way the wheel gets tighter.
5. Repeat on the other side.
6. Back inside, work the lever a few times to seat the cables, then release it. Pull the lever up six notches and tighten each cable nut until its rear wheel can no longer be turned by hand. Keep both sides even.
7. Release the lever and confirm both rear wheels spin freely. Pull the lever and confirm the parking brake warning light comes on.
8. Refit the lever boot, reinstall the wheel bolts, lower the car and torque the wheel bolts to the value in the factory service manual.

If one wheel locks and the other still spins after adjustment, do not keep tightening that side's cable. It usually points to a seized adjuster, a sticking expander or a binding cable on the side that still spins.

Replacing Shoes, Hardware or Cables

If adjustment does not fix it, the rotor has to come off. Per Pelican's shoe replacement guide, that means slackening the cables, removing the caliper and bracket (hang it on wire, never by the hose), removing the rotor's small retaining screw and sliding the rotor off. If the rotor will not come off, the shoes are catching on a worn lip, so back the adjuster off first. The shoes come out after unhooking the lower return spring and turning each retaining clip 90 degrees. Plan on about two hours for both sides.

While it is apart:

• Replace the shoes and hardware as a set. Springs and clips on a car this age have lost tension. Brake shoes and hardware kits are in our parking brake shoe selection and brake hardware kits.
• Inspect the backing plate around the retaining-clip holes for rust. A weak plate will let a clip pull through again.
• Clean and check the adjuster. It should turn freely along its full length. Replace it if the threads are rough.
• Lightly grease the shoe contact points on the backing plate with brake grease. Keep grease off the linings.
• Check the drum surface inside the rotor hat. If you are replacing the rear rotors anyway, this is the time to do the shoes. See our brake rotors and brake pads.

Cables are a bigger job. ZRoadster's write-up notes they come out with the wheels, calipers, rotors, shoes, expanders and springs removed, and warns about a very small pin that joins the cable eye to the expander, which is easy to lose. New cables sometimes need light fettling to fit. If one cable is seized, replace both so the two sides pull evenly.

How Hard Is the Job?

Adjustment is a beginner-friendly job if you can lift the car safely. The only tricky part is working the star wheel blind through a bolt hole. Shoe replacement is an intermediate job, mainly because of the springs and the fiddly retaining clips. Do one side at a time so the other side is a reference. Cable replacement is the longest of the three because of how the cables route under the car.

If your Z3 also needs front brake work, we carry parts matched to its engine. For the 1999-2002 Z3 2.5 that includes EBC Greenstuff front brake pads and EBC USR slotted front rotors. For the 1996-1998 Z3 1.9 there are EBC Redstuff ceramic front pads. For the 2001-2002 Z3 3.0 there is the EBC BSD V-slot front rotor pair.

Frequently Asked Questions

How many clicks should a BMW Z3 parking brake take?

A properly adjusted Z3 locks the rear wheels within roughly five to six clicks. Pelican Parts recommends adjustment once the lever reaches 10 clicks or more.

Can I adjust the Z3 parking brake without removing the wheels?

Yes. Remove one wheel bolt per side and reach the adjuster through that hole with a flathead screwdriver. Adjusting with the wheel bolted on is the recommended method.

Why does only one rear wheel lock when I pull the lever?

One side is out of adjustment, or its adjuster, expander or cable is seized. Adjust both sides at the wheel first, then set the cables evenly. If one side still will not lock, remove that rotor and inspect it.

Does the Z3 have rear drum brakes?

No. The Z3 uses rear disc brakes for normal stopping. The only drum is the small parking brake drum built into the inside of each rear rotor hat.

What causes a grinding noise from the rear of a Z3?

Worn rear pads are the first suspect. On a Z3 it can also be a parking brake shoe whose lining has come loose, or a shoe whose retaining clip has pulled through a rusted backing plate and is rubbing the rotor. Pull the rotor to check.

Should I adjust the parking brake after new rear rotors?

Yes. Readjust the shoes at the wheel and then the cables after any rear rotor replacement. The new drum surface and backed-off shoes leave the lever travel long until it is reset.

Sources

1. Pelican Parts - BMW Z3 Parking Brake Adjustment (1996-2002) - drum-in-hat design, 10-click check, adjustment procedure, 18 catches (8 on M3) per BMW, six-notch cable setting, warning light check
2. Pelican Parts - BMW Z3 Parking Brake Shoes Replacement - lining separation, rusted backing plate clip failure, removal steps, greasing contact points
3. ZRoadster - BMW Z3 Parking Brake Cable Replacement - sheath splits and cable corrosion, removal scope, expander pin warning, 5-6 click target
4. BimmerWorld - Parking Brake Adjusting Screw (Z3 fitment) - Z3 fitment, part number 34-41-6-851-438, screws jam with brake dust and corrosion
5. BimmerWorld - Parking Brake Shoe Set (Z3 fitment) - Z3 fitment, replace shoes if brake will not hold after adjustment