2015-2016 Chevrolet Colorado Parking Brake Problems and Adjustment

By Core Brake Parts Tech Team — Circleville, OH warehouse

The 2015-2016 Chevrolet Colorado uses a foot-operated parking brake that pulls a cable to a small set of brake shoes hidden inside each rear rotor, a design called drum-in-hat. When the parking brake feels weak, the pedal goes nearly to the floor, or the truck rolls on a grade, the fix is usually adjusting those shoes first and the cable second, not just cranking the cable tighter.

How the Colorado Parking Brake Works

The second-generation Colorado came with four-wheel disc brakes as standard equipment. The rear service brakes are conventional calipers and pads, but the parking brake does not use them. Instead, the center "hat" section of each rear rotor is machined inside like a small brake drum, and a pair of parking brake shoes sits on the backing plate inside it. Stepping on the parking brake pedal pulls a cable that spreads those shoes against the inside of the hat.

A few details from the GM owner's manual for this truck matter when you diagnose problems:

• It is a pedal, not a hand lever. GM's procedure is to hold the regular brake pedal down, then push the parking brake pedal down to set it.
• To release it, hold the regular brake pedal, push down momentarily on the parking brake pedal until it releases, then let your foot up slowly.
• With the ignition on, the brake system warning light comes on whenever the parking brake is set, and a RELEASE PARKING BRAKE message can appear in the driver information center.
• If you start driving with the parking brake still applied, the warning light flashes and a chime sounds.

Because the parking shoes rarely do any stopping, they wear very slowly. The common problems are not worn-out shoes but shoes that are out of adjustment, a stretched or seized cable, or shoes that were disturbed during a rear brake job.

Common Parking Brake Problems and What They Mean

One point from the manual is worth underlining: the brake system warning light that comes on with the parking brake also warns of low brake fluid and other brake system faults. GM states that if the light stays on after the parking brake is fully released, the vehicle has a brake problem. Do not assume a stuck light is only the parking brake switch until you have checked the fluid level.

How to Test the Parking Brake the GM Way

The Colorado maintenance schedule calls for checking the parking brake and the automatic transmission park mechanism as part of routine inspections. GM's owner's manual describes the test:

1. Park facing downhill on a fairly steep grade with clear room in front of the truck.
2. Keeping your foot on the regular brake, set the parking brake.
3. With the engine running and the transmission in Neutral, slowly lift off the regular brake until the truck is held by the parking brake alone.
4. To test the Park mechanism separately, shift to Park, then release the parking brake followed by the regular brake.

Be ready to apply the service brake at once if the truck starts to move. If the parking brake cannot hold the truck by itself, it needs adjustment or repair. Leaning on the transmission Park pawl to hold a loaded truck on a hill is exactly what the parking brake is there to prevent.

Adjusting the Parking Brake: Shoes First, Cable Second

The most common mistake on drum-in-hat systems is tightening the cable to make up for shoes that are backed off. That takes up the slack for a while, but it pulls the cable toward the end of its travel and can leave one side doing most of the work. The correct order is:

1. Back off the cable. Loosen the parking brake cable adjustment so the cable is not holding the shoes out while you set them.
2. Adjust the shoes at each rear wheel. Each parking brake assembly has a star-wheel adjuster between the shoes, reached through an access hole in the rotor hat or with the rotor removed. Wilwood's own procedure for internal drum parking brakes is to expand the shoes until the drum cannot be turned by hand, then back off just enough that it turns, with slight drag acceptable.
3. Match both sides. Adjust left and right the same way. If one side is set tighter, the cable will load that side first and the other shoe will barely contact the hat.
4. Set the cable. Take the slack out of the cable at its adjuster so the pedal applies firmly without the shoes dragging when released. Cable adjuster location and the exact pedal travel target are in the GM service information for your truck.
5. Verify. With the parking brake released, both rear wheels should spin freely. Then repeat the hill-hold test above.

Wilwood also warns against applying the parking brake with the drum removed. The same applies here: if you step on the pedal with a rear rotor off, the shoes spread out of position and the adjuster can come apart.

When Adjustment Is Not Enough

If the shoes are adjusted correctly and the parking brake still does not hold, open it up and look for these problems:

• Contaminated shoes. Grease from a leaking axle seal or brake fluid from the rear caliper can soak into the lining. Contaminated shoes will not grip; replace them and fix the leak.
• Glazed or worn shoes. Shoes that were driven with the parking brake partly applied can glaze. Replace them as a pair on the axle.
• Worn or scored rotor hat. The inside drum surface can be grooved or rusted. The drum section is part of the rotor, so a badly worn hat means a new rotor.
• Seized or frayed cable. Rust inside the cable sheath, especially in salt-belt trucks, can keep the shoes from applying fully or from releasing. A sticking cable often shows up as one rear wheel running hot.
• Broken hardware. Return springs, hold-down springs and the adjuster can corrode or break. Replacing the hardware along with the shoes is inexpensive insurance.

What to Replace Together

Most parking brake work on this truck happens during a rear brake job, because the rear rotor has to come off to reach the shoes. That makes it the right time to inspect everything inside the hat:

• Parking brake shoes, as a pair per axle. GM's manual states that brake linings should always be replaced as complete axle sets.
• The shoe hardware and adjusters. See our brake hardware kits and brake shoes.
• Rear rotors if the hat surface is scored or the braking surface is worn. For the 2.5L Colorado we carry the EBC GD7702 slotted rear rotor set, and the matching EBC GD7701 front rotors if you are doing both axles. Browse more in brake rotors and brake pads.

When the new rear rotors go on, set the parking shoes using the procedure above before the wheels go back on. A fresh rotor hat with an unadjusted shoe is the classic cause of a parking brake that sinks to the floor right after a brake job.

Also keep the hydraulic side healthy. The Colorado uses DOT 3 brake fluid, and the maintenance schedule calls for replacing it at 45,000 miles or every three years, whichever comes first. Front brake calipers on some 2015 Colorado trucks were the subject of NHTSA recall 15V278000 for possible fluid leaks, so have the VIN checked for open recalls whenever the brakes are serviced.

How Hard Is the Job?

Adjusting the parking brake is a moderate driveway job: jack stands, wheel removal, a brake spoon or flat screwdriver for the star wheel, and access under the truck for the cable adjuster. Replacing the parking shoes is more fiddly. The springs are small and the shoes must be seated correctly in the adjuster and anchor, so take a phone photo of one side before you take it apart and work one side at a time. Rear rotor removal requires taking off the rear caliper and bracket; torque every fastener and the wheel nuts to the values in the GM service information.

Frequently Asked Questions

Does the 2015-2016 Colorado have rear drum brakes?

No. It has four-wheel disc brakes. The only drum on the rear is the small parking brake drum machined into the center hat of each rear rotor, with its own pair of shoes.

Why does my Colorado parking brake pedal go almost to the floor?

Usually the parking shoes are backed off too far, which is common right after the rear rotors are replaced. Adjust the shoes at each wheel first, then take up the cable slack.

Can I just tighten the parking brake cable?

It may help temporarily, but if the shoes are out of adjustment you end up with an unevenly applied brake and a cable near the end of its travel. Set the shoes first, then the cable.

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

The same light warns of low brake fluid and other brake faults. GM says if the light stays on after the parking brake is fully released, the vehicle has a brake problem. Check the fluid level and have the system inspected.

Do the rear pads affect the parking brake?

No. The rear pads and caliper handle normal stopping, and the parking brake shoes inside the rotor hat work separately. Replacing rear pads does not require touching the parking brake unless the rotors come off.

How often should the parking brake be checked?

GM includes a parking brake and Park mechanism check in the Colorado's routine inspection items. Doing the hill-hold test at every tire rotation is a simple habit.

Sources

1. 2016 Chevrolet Colorado Owner's Manual (GM) - parking brake apply and release, warning light and chime behavior, park brake hold test, DOT 3 fluid, axle-set linings, three-year fluid interval
2. National Oil and Lube News - Tech Spec: 2015 Chevrolet Colorado - four-wheel disc brakes standard, DOT 3 fluid, 45,000-mile brake fluid replacement, parking brake check in maintenance
3. NHTSA recalls - 2015 Chevrolet Colorado - recall 15V278000 front brake caliper fluid leak; no parking brake recall listed
4. Wilwood - How to Adjust the Internal Drum Parking Brake - shoes-before-cable adjustment method, do not apply with drum removed