Parking brakes stuck

Have a friend with a 2005 Impala 3.4L with 4 wheel disc breaks. Earlier today she parked on an incline and used the parking brake for the first time in a long time. Now something is stuck. Like the parking brake is about 90% engaged. Moving in reverse seems to work ok, but trying to go forward requires some gas just to get the car to move and once you are moving both rear brakes squeal like crazy. I've never had a car with 4 wheel discs and never worked on one so I'm not sure what we will find. But I have no problems digging into it. The brake cable is moving freely from front to rear. The pedal locks and unlocks as it should. But the independent cables that go to the left and right wheels are not moving so something is stuck likely at the wheels. I'm guessing rust and dirt buildup is preventing the things from freeing up and am hoping a simple cleaning and WD40 may free them up. We have at least a foot of snow forecast for Sunday, it would be nice to take care of it tonight. Thanks for any help.

Have a friend with a 2005 Impala 3.4L with 4 wheel disc breaks. Earlier today she parked on an incline and used the parking brake for the first time in a long time. Now something is stuck. Like the parking brake is about 90% engaged. Moving in reverse seems to work ok, but trying to go forward requires some gas just to get the car to move and once you are moving both rear brakes squeal like crazy. I've never had a car with 4 wheel discs and never worked on one so I'm not sure what we will find. But I have no problems digging into it. The brake cable is moving freely from front to rear. The pedal locks and unlocks as it should. But the independent cables that go to the left and right wheels are not moving so something is stuck likely at the wheels. I'm guessing rust and dirt buildup is preventing the things from freeing up and am hoping a simple cleaning and WD40 may free them up. We have at least a foot of snow forecast for Sunday, it would be nice to take care of it tonight. Thanks for any help.

not sure on a 2005 , but on earlier vehicles the park brake is also the caliper brake. the caliper is connected to the cable and it is very possible this caliper is defective. the piston rotates to engage the brake pads to the rotor.

One time on an earlier year vehicle , the rear brake pads rusted to the rotors. I had to chissel of the pads from the rotor. this vehicle was just not used for a few months parked on pavement..

The cable actuates a lever on the lower side of the wheel hub. This lever operates a cam which drives a one-piece brake shoe inside the small drum portion of the interior of the rotor hub. The rotor/parking brake drum can only be removed by removing the caliper bracket. Once the caliper bracket is removed the rotor can be removed, although if the park brake shoes are stuck this might be difficult. Sorry I don't have a better photo, but it is apparent by the oversize of the hub of the rotor that it is also a drum:

http://www.wwdsltd.com/files/W-ImpalaRearBrakeAssy.jpg


Try to manually release the park brake actuator at the wheel by moving the lever rearward (opposite the direction of the cable pull). Apply penetrating oil at the shaft attached to the lever, since corrosion there is likely why it is stuck.

http://www.wwdsltd.com/files/GMFWDParkBrakeLever-Cam01.jpg


Once you have released the park brake and removed the rotor/drum, clean up the drum and shoe, and lubricate the shaft from both ends . Operate the shaft until it works freely.

http://www.wwdsltd.com/files/GMFWDParkBrakeShoe01.jpg


When finished, advise the driver to ALWAYS use the park brake so that this doesn't happen again. Failing to use the park brake properly places tremendous stress on the relatively frail differential planet gears in the transmission. You don't want this if someone bumps into the parked car in a lot:

http://www.wwdsltd.com/files/4T60EDifferentialDamage.jpg

Excellent reply Blue Bowtie, thank you. Unfortunately it is snowing heavily now and the car is at a house with no garage and is undriveable especially in the snow. But I will go over there and at least try to get it unstuck without having to take much apart. Then wait for better weather for more in depth repairs.

I'd say I'm sorry about the weather, but only a hundred miles SW of you we're getting freezing rain. I'd actually rather have the snow.

You might be able to just get behind the backing plate/hub and force the levers to the released position and work on freeing up and properly lubricating the mechanism later.

I did just that, forced the levers back and the brakes are released. It's driveable again and everyone is happy. Told her to not apply the E-brake until more work can be done. Thanks for your help. The photos and sketches were priceless.

For those of you in the warmer climates who's cities shut down when you get 2" snow. I had to drive my light weight Saturn SL2 about 8 miles through 5" of unplowed fresh snow with visibilities of about 1000 feet. Like taking a walk in the park, except a whole lot more fun.

Stay warm.:iceslolan

Laugh about your Saturn if you want, but one of the best winter trips I've had was from Curly's on Lombardi down through Milwaukee (on 41 instead of past your place) and home down 43 across the line just into Ill-Noise. It was constant snow on top of snow pack and ice all the way. Semis and other cars were doing 25 at best. Everyone and everything was in the ditches, including plows. My wife, me, and a manual Fiero averaged about 45 all the way. As long as it didn't belly out on 4½" of snow (ground clearance) that was among the best winter cars I ever drove.

Glad you got your friend going for now.