[skidazzle98]

Whenever I'm going on Hwy speeds 65-70mph+++ and need to brake quickly and hard(like the kind of braking when someone cuts in front of you or when the traffic lights changing), especially right after I'm accelerating, my brake pedal seems to push against my foot like it doesn't want to go down. It happens in a down / up kind of way. It's hard to explain, but when I step on the brake pedal it will go down and then the pedal seems to push back( This continues quickly until the speed is slows down to about 55mph). When this happens my car starts to go out of control, but I've been lucky enought to have a steady arm to keep the car in control.

Has anyone ever had a problem like this? It doen't happen in low speeds in city driving no matter how quickly or hard I brake. The brake is not vibrating, just the pedal doesn't seem to want to go down. This problem has almost caused me to get into a couple of accidents.

ABS problem??? This has been happening for about two months now. Had my front rotors turned and all four brakes replaced.

Sorry for the long post. Any help will be appreciated

 

[KNLNGUS]

It sounds like the ABS is kicking in - vehicle speed, brake fluid pressure from the master cylinder (applied by the brake pedal) and the sensor at each axle all play well into the operation of the ABS.

The first part of your paragraph

"...my brake pedal seems to push against my foot like it doesn't want to go down. It happens in a down / up kind of way. It's hard to explain, but when I step on the brake pedal it will go down and then the pedal seems to push back( This continues quickly until the speed is slows down to about 55mph)."

This sounds so much like how the ABS feels. Pulsing on the pedal. Can be a dull kind of pulse or a total rapid pulse.

But then again, if you are at 55-75mph and you hit the brakes in an emergency fashion and your rotors are warped, your pedal will pulsate and can make a muffled sound.

Then you mention........

"When this happens my car starts to go out of control, but I've been lucky enought to have a steady arm to keep the car in control."

A bit confused here as the only thing that should happen when your brakes are applied is a reduction of speed. If your ABS kicks in, you will feel a pulsation on the brake pedal because the actuators are compressing the brake fluid in a pulse manner to each caliper (all, one, or some). This action should not affect the steering at all.

So I will assume starting to go out of control means, maybe your car jerks back and fourth (even this is a wild thought though)?

I definitely want to help and need the help of others on the forum here along with a bit more specifics.

Your steering wheel developes a shimmy (right to left) ONLY when the brakes are applied?

I just keep going back to the fact that you had all the rotors turned and i'm a bit stumped.

KNLNGUS

 

[skidazzle98]

"A bit confused here as the only thing that should happen when your brakes are applied is a reduction of speed. If your ABS kicks in, you will feel a pulsation on the brake pedal because the actuators are compressing the brake fluid in a pulse manner to each caliper (all, one, or some). This action should not affect the steering at all. "

"So I will assume starting to go out of control means, maybe your car jerks back and fourth (even this is a wild thought though)? "

When I have to put on the brakes quickly (only on high speeds 65 and above), and the pulsation starts, my steering wheel will either jerk quickly to the right or left (It doesn't jerk back and forth). It's not consistent, sometimes to the right and sometimes to the left. During any other time I brake the wheel never turns, I can literally let go of my steering wheel and the brake applied, it will slow down straight.

From high speeds I will get a small pulsation action on the pedal even when I don't have to slam on my brakes. It is short but it still gives me a small pulse action. I've had my car for about a year and never felt this before ever. In any situation. It just started about 2 months ago.

I've driven other cars w/ abs and nothing feels like the problem I'm having. It just doesn't feel common to have a the abs kick in for no reason. When this first happened to me, It scared the sh*t out of me. I felt like the brakes were going out on me. That's not a good feeling. But I've been able to work around the problem. Basically, when driving on the Hwy, I would stay as far from other people as possible. And also, I would let go of the gas and let the car to slow by itself for a couple of seconds before I step on the brakes.

If no one here has ever experience this type of problem, then there must be something wrong since it is not common.

 

[James92LS]

Sounds to me like one of your brakes aren't working...

For example... if you brake really hard and your front brake right DOESN'T work, your car will severely pull to the left, since it is doing much more braking than the right....

Don't know how you could test this, perhaps a bleeding of the brake system would be useful?

Either way, sounds like a mechanic should take a look, that is dangerous!

-James

 

[KNLNGUS]

skidazzle98 - Hmmmm.

James92LS, you have an okay idea.... but skidazzle98 wrote.... "It's not consistent, sometimes to the right and sometimes to the left" and we don't even want to get into any "brake not working" statements.

Now, skidazzle98, you had me theorizing because you eliminated the possibilities with your statement.... "Had my front rotors turned and all four brakes replaced." When in actuality I should have asked when were your rotors and brakes (I will assume brake pads) replaced.

I read your post as if you are experiencing this problem then you had your front rotors turned and all four brakes replaced in an attempt to correct the problem.

NOW, with your reply to my original post eliminating my different view(s) of what could be happening - I will refer you to a common problem everyone with disc brakes experiences when your Rotors are warped. Your vehicle steering wheel is pulsing, vibrating, shimmying (don't want to get caught up in words here) and your pedal feels the way it does because your booster is working, your master cylinder is sending or pressurizing the brake fluid and your caplipers are compressing the brake pads onto WEEEEEEEEEEEEEorped rotors. Stock rotors especially those that are aged and close to the spec limit can warp very easily.

Anyone concur?

KNLNGUS

 

[James92LS]

Re: skidazzle98 - Hmmmm.

James92LS, you have an okay idea.... but skidazzle98 wrote.... "It's not consistent, sometimes to the right and sometimes to the left" and we don't even want to get into any "brake not working" statements.

Now, skidazzle98, you had me theorizing because you eliminated the possibilities with your statement.... "Had my front rotors turned and all four brakes replaced." When in actuality I should have asked when were your rotors and brakes (I will assume brake pads) replaced.

I read your post as if you are experiencing this problem then you had your front rotors turned and all four brakes replaced in an attempt to correct the problem.

NOW, with your reply to my original post eliminating my different view(s) of what could be happening - I will refer you to a common problem everyone with disc brakes experiences when your Rotors are warped. Your vehicle steering wheel is pulsing, vibrating, shimmying (don't want to get caught up in words here) and your pedal feels the way it does because your booster is working, your master cylinder is sending or pressurizing the brake fluid and your caplipers are compressing the brake pads onto WEEEEEEEEEEEEEorped rotors. Stock rotors especially those that are aged and close to the spec limit can warp very easily.

Anyone concur?

KNLNGUS

Sounds good to me... I still think it could be an issue with brake bleeding.... I don't know the details on how it works, but could it be that the air bubble could move to different parts of the braking system? Sometimes causing the front left to not work, and other times the front right?

Just an idea.

-James