Power assist suddenly gone from the brakes!!!
 

I had an accident this Saturday. I was driving down on a bridge quiteslowly, at about 20 mph.At the end there was a pickup waiting for the traffic light.

So I pressed the brake but shockingly there was no effect. Then I pressed it again, real hard but still nothing only a very little deceleration. All I could do is to watch the tail of the pickup coming closer and closer. And then to see how the hood of the Mustang crumples before me... :(

It was raining before, so the road was still wet, BUT thecar did NOT skid, the ABS did NOT rattle, it seemed that the power assist gone like when the engine was not running (however it was for sure). I should have stop very easily it was a routine stuff.

It is a bit scary, what if I lose the brakes on a highway at 70mph...


Does anybody have any idea how could it happen that the car loses the power brake assist?

RE: Power assist suddenly gone from the brakes!!!
 

sorry it happened to ya.....hope your stang gets
fixed up real soon

also i don't know much about the brake system, but
i see that some ABS circuitry runs through the
smart junction box......

has your vehicle ever leaked water into the passenger foot
area....



[IMG]local://upfiles/37808/1F5654B89EA94954841D9E21F634F58C.jpg[/IMG]

RE: Power assist suddenly gone from the brakes!!!
 

Don't know! Master Cylinder?

Crazy Al, any opinion?

RE: Power assist suddenly gone from the brakes!!!
 

Sorry to hear that. Damn:( . But the emergency brake is right there for that very reason.

I've been there though. you were in a bit of a panic and didnt think of it at the time. Dont worry about it. you'll get it fixed up.

RE: Power assist suddenly gone from the brakes!!!
 

ABS is on the same circuit as Ignition, so if it starts, you have power to the ABS.

Have you bleed your breaks lately? There is a piston inside the master that if it goes past center will make your breaks system crappy.
The perporsioner valve delivers pressure to the Front and Back in a different rate, If the front line gets plugged or the valve gets stuck the front breaks will not work.
Is your Break light on in the dash?

RE: Power assist suddenly gone from the brakes!!!
 

Thank you all! You guys are really kind!

Well, it's not about the ABS. The ABS had no chance to be activated since the brake itself did not work so the car could not skid. I'm talking about the power assist that gives the extra power when you press the brake pedal. Of course I could pull the emergency brake but I had about 5 seconds... And I used the first 3 to realize my situation... ;)

After the accident I had the system back so it works now. I have no Break light on in the dash, I might had it in that time but I don't remember. I didn't notice any leaks nor strange behaviour before the incident.

The pony is at Ford and will be ready end of next week. I hope it will look like originally.

RE: Power assist suddenly gone from the brakes!!!
 

Try the vacuum check valve.
It might be bad.

RE: Power assist suddenly gone from the brakes!!!
 

Sounds to me as though the Brake Booster loss vacuum or failed which is pretty rare.

Richard

RE: Power assist suddenly gone from the brakes!!!
 

Here come the flames...did your throttle stick? (Ducks for cover)