ive noticed the last couple days as soon as i shut the engine off, even if the key is in the forward position the breaks lock in an unbreak position, and do not allow me to put the break down at all. A couple times i started rolling down a hill almost hitting another car before i ripped ont he hand break, and dropped the clutch. Why is this all the sudden happening? As soon as i hit engine start- all is well.

 

I don't know what you mean by "the breaks lock in an unbreak position, and do not allow me to put the break down at all." Btw, it's spelled brake's.

Your brakes are not locked, and can be pressed down. What is happening, you are pressing down on the brake pedal after you have shut off your engine. You do this three or four times and you lose the vacume inside of your brake booster, hence your pedal get stiff and loses travel. If you put some weight on the pedal, (stand on the biotch) it will stop your car.

When the engine is started, your brakes return to normal. Unless your power booster is going out, there is nothing wrong with your brakes.

 

sorry. Long day of studying = spelling skills not up to par. I stomped on brakes pretty hard, continued to roll back.

Brake locked, in unbrake position
...Locked out of being able to be pressed down. Brake is stiff, would not go down, cant stop car from rolling

 

pretty much any car will do this. if the engine is off, you will not be able to use the brakes with your foot. this is totally normal.

 

Sorry Matt, but that is completely wrong.

The normal braking system is supposed to act even with the engine shut off. The only thing that can happen is that the (vacuum) booster is not working anymore, which would require more pedal force. However, when 'stomping' on the pedal, the brakes should normally engage!

This is a very unusual problem and I'm wondering if there is any problem with the ABS module. It sounds like it is malfunctioning one way or another, maybe the valves are stuck or something like that.

My advice to DDuds2k: find some empty(!) piece of road, drive and brake hard to engage the anti-lock system. See if there is a problem there.

Do you have the ABS light on? Did you recently change brake fluid or something? What kind of mods do you have??

This is weird and totally abnormal!


Siepel

PS: Is there something under your brake pedal????

 

You stated in your own paragraph here exactly why it WONT work if the engine is off. "the only thing that can happen is that the vacuum booster is not working anymore, which woudl require more pedal force".

uh, if the engine is not running, the booster will not have any vacuum.



I just tried it in my fiancee's corolla here at work.

I went out, turned the car on, started it up, and the brake pedal was nice and squishy and the brakes worked great.

turn the engine off, and viola. brake pedal hardened to the point where I could not even push it down after only 1 or 2 pumps. brakes were pretty much useless and could not apply any brake pressure.

I then turned the engine on again, and once again it was nice and soft and the brakes worked. this time, i shut the engine off, but then turned the key back to the on/running position. and viola, the brakes once again were hard and almost useless after only 1 or 2 pumps on the pedal.

the engine MUST be running in order for it to create the vacuum needed for the brake lines.


soooooo....... how was I wrong?

go out in your S2000 and try it, and then you come come back and go

 

[QUOTE=Wisconsin S2k,Feb 23 2006, 09:18 PM]I just tried it in my fiancee's corolla here at work.

I went out, turned the car on, started it up, and the brake pedal was nice and squishy and the brakes worked great.

turn the engine off, and viola.

 

I think you are both right. Without the vaccum boost the breaks are pretty much useless. That the purpose of the vacuum- to make the break pedal pressure needed to activate the calipers much easier. However, if you could get an elephant to stomp on the breaks with no vaccume pressure the brakes should still work. It just takes an unreasonable amount of force to activate the hydraulics.

 

hehe, I think the difference is that I consider having to use 100+ lbs. of braking force to brake makes the brakes essentially useless. but i understand what you're saying.

we're both right.


but anyways, in regards to the original poster, my point is that this is totally normal and there is nothing wrong with the car.

 

i guess i should have read before I posted.