Emergency Brake

kenny jacobs · January 7, 2004

Hello all. I will be changing the brakes on my 2000 LS Z-71 this weekend and was wondering how the emergency brake works? This is my first 4 disc braking system experience. That is where I am lost. Hows does the back brakes engage? I pushed the emergency brake pedal down earlier and put the truck in drive, and it started rollin g forward without me pressing the gas pedal. Is that normal? I wouldnt think so. All help will be appreciated. Thanks, Kenny

Ben · January 7, 2004

Double check your glove box manaul. Bet it has NO reference to Emergency anything brakes.

Whimpy rear PARKING brakes are drum/shoe brakes inside the disc rotor hub.

From the looks of them, don't think they can stop a truck going more than 20 mph and if can, not more than couple times.

JayMan · January 7, 2004

The "parking" brake GM decided to use for the +1999 trucks is really wimpy. It's called a "drum in hat" system since the rear rotor has a small drum inside for really tiny drum brake shoes.

They look like the drum brakes from a 1930's car. Adjusting them is critical to get them to work properly, or they don't work at all. I get the dealer to adjust mine once a year, which he does as part of the yearly inspection. So my "parking" brake seems to work and hold well.

The adjusting procedure is complicated. According to the Helm manual, you need a special gauge, have to measure the diameter of the rotor drum (An oxymoron if there ever was one), then adjust the shoes to this special gauge. The gauge has compensation to allow "just enough" clearance so the shoes don't drag.

Big drums make the best parking brake, but disk brakes offer superior stopping and control. Most cars with 4 wheel disk have a lever system that forces the brake puck against the rotor, but this is also a weak system. The puck only contacts a small part of the rotor.

I've had commercial equipment with a real "emergency" brake off the transmission: a large hub with a big shoe inside. They work VERY well, though if the driveshaft broke it wouldn't work at all.

It's all a compromise, isn't it??

Ben · January 8, 2004

One thing always check on any new to me vehicle is the "Emergency" brakes. Whether rental or borrowed.

Now that know about the "non" existant Emergency brakes of new GM trucks, will know once gone through the main brakes, it's over.

Even sweetie's sedan with 4 wheel disc has mini drum/shoes inside the rear rotor hub. It WILL skid to a stop with the hand brakes...aka Emergency/parking brake.

This one snuck up on the general public. Wonder if the other badges did same?

Makes me think it's illegal or some. I'll not place this in the "compromise" bucket. It's necessary, IMHO.

Taaaaaaahoe? · January 8, 2004

Emergency Brake, How does it work?

it dosen't

GnatGoSplat · January 8, 2004

This one snuck up on the general public. Wonder if the other badges did same?

Makes me think it's illegal or some. I'll not place this in the "compromise" bucket. It's necessary, IMHO.

It's been this way for awhile. The park brake in my wife's old 88 Cutlass Supreme is not referenced in the owner's manual with "emergency" anywhere either.

Plus, those cars had a pump-to-set park brake where you had to pump it 3-5 times to set the park brake. Not too useful in an emergency.

tmoreau · January 8, 2004

Out of my twelve cars/trucks that I have owned, I think less than half of them have had working parking brakes. My silverado is the first manual trans vehicle that has a working parking brake, and it stopped working at 15k miles. I had it fixed at 35k under warranty, but dont much trust it. I think they are a VERY good thing to have, if (when?) your brakes fail its nice to have another way to slow down. I speak from expierience:

I had the brakes on my 92 s-10 5spd v6 go out once. I was sitting at a stoplight and pushed the brake pedal a little harder because something felt funny. As soon as I did the pedal went to the floor and I started rolling back. Had to constantly inch up/ clutch/ roll back to avoid hitting the cars in front of me and behind me. (Dont try this while learning stick!) Anyway, I didnt have a working parking brake but still went on to the taco bell drive through and drove the two miles home. I could press the brake pedal VERY lightly and get a little braking but any harder and I would lose it all. After all that, I nearly hit the garage door when I got home. It turned out that the rubber hose by the left front wheel split along the length of the hose about an inch long and puked most of my fluid out.

I thought that the reason for separate front/ rear resivoirs was so that I would still have rear brakes in this scenario, but I guess I was worng. One little split, no brakes at all. Would have been a real nightmare if it was an auto trans and happened during a panic stop from 40mph!