BSmith

So I drove my wifes 07 Cobalt that she has always said the brake pedal heght changes. (Was in for service one time and they said nothing was wrong) So here is what happened today.

When first starting the car the brake pedal goes 3/4 to the floor the first push. Then it is fine. (about 2/3 travel. Then after a few miles the pedal travel starts to shrink. Goes to 1/2 then to a 1/4 till finally it's right at the top and touchy as hell. (not even enough travel to have the brake lights come on) The car actually won't roll. If you turn it off and wait 10 minutes....start the car and the cycle starts again.

It actually started to lock up on the expressway and I had to pull over and wait till it unlocked.

Now this happens 50% of the time. Chevy drives it and it does not happen. They don't drive it long enough. To me in my limited dealings with anti lock and such it sure sounds like a master.

Car has 2000 mi on it.

We are dropping it off Monday to try again.....

Ideas???

BSmith

Anyone??

SLJ2137694

I would suspect something is causing a brake dragging condition, such as aftermarket floor mats bunching up and hitting pedal, mis-adjusted brake light switch, brake booster push rod too long, rubber brake hose acting as a check valve and holding pressure on part of the brake system, master cylinder problem, under dash sound insulator hitting brake pedal, contaminated brake fluid, riding the brakes and being unaware of it, etc. Keep us posted on this issue.

BSmith

Thanks Steve,

They called and said they ordered a brake booster. How that can change pedal position and lock the brakes is beyond me. Does it sound right?

SLJ2137694

If a brake booster has been ordered I ASSUME they measured the length of the master cylinder push rod and found it too long. These push rods in the past were serviced with an adjustable push rod but in recent years the only way to obtain one was with a new booster. When the booster is assembled a push rod of the correct length is selected and installed. If a push rod that is too long is installed it will hold slight pressure on the master cylinder just as if you were riding the brakes. This can cause the brakes to overheat and/or drag. As you can imagine this issue is rare and the symptoms happen right away on a new car. As I said, if your push rod was too long I am sure you are on the way to a successful repair of this issue. In my 20+ years of handling brake issues I have only seen this happen a handful of times.

BSmith

Car picked up with booster installed. 10 miles down the road and the pedal is up again and very touchy. What the hell?

BSmith

Now a brake switch has been ordered. Looks like they are reaching now. Man I hate to start a lemon law fiasco.....

beckeruti

if they cant fix it on the third time tell them to give you a new one
and raise hell and get like a years worth of oil changes
extra tires or something
find the local lemon law lawyer that dealers hate and mention his name


good luck

jmariner

I'm having the same problem with my 07 SS/SC. The calipers are "Lazy" and are causing adangerous condition. I apply the brakes to stop at an intersection (for example) and when proceeding, I have to add unreasonable power to get the car going again and when shifting into second gear, I damn near go through the windshield when I depress the clutch!
Somemoments are worse than others but it's obvious that these calipers don't want to reset to the propper position. On various Cobalt specific forums, virtually everyone has had trouble with their rotors warping and clutches cooking prematurely..............it's pretty obvious to me that the calipers are the culprit (dragging and overheating the discs).
It becomes REALLY obvious in bumper to bumper traffic (clutching and braking constantly)where the calipers simply don't release fully.
Keep me posted on this matter. I'll be visiting my dealer A.S.A.P aswell.

danzel

good performance of my Chevy ebc brakes, i've been for a long trip and nothings bad happened to me on the road because it has high-performance compounds and even ultra heavy-duty endurance, this is one of another reason i should consider installing EBC brakes on my vehicle. it gives me more comfort and safety
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