Background on car.
03 Enthusiast, 12x,000 miles, Hawk HPS pads, Stock calipers, hoses, rotors, Kinetix Upper Intake Mani.

A couple mornings ago, my wife was driving the car, went to hit the brakes and it didnt stop. She said it felt normal, but didnt stop. She took the other car, when i got home i took the Z out for a long drive and never could recreate it. She calls me yesterday and said it did it again, so it seems to only be doing it first thing in the morning.

So this morning i get up and before i go to work, take it around the block. The first 3 or 4 times i hit the brakes, it was fine. Then the pedal got real stiff, feels like the Booster has gone bad.

Before i go condeming a booster, short of the vacuum hoses, is there anything else i should check. I did search, found one thread where someone who was FI had this problems, and the only response was check your PMs, then the OP saying that fixed it....But it never said what the fix was.

I also found a thread where people were saying to take off the cap for the wheel sensors and clean it up. I do not recall a ABS/Brake/Slip light ever coming on, so im kind of ruling this one out, your thoughts?

This morning i did not have any time to do any troubleshooting. I do not know if there was vacuum getting to the Brake Booster or not, assuming yes, any other things i should check before replacing the booster?

Thanks in advance

Keith

 

try a fluid flush

 

Sounds like a booster to me.

 

Most brake boosters pull vacuum from the intake manifold. Check the hose to make sure it isn't loose or cracked, as well as the fitting on the manifold itself. Could be a low temperature leak that gets sealed up as the parts warm up and expand.

 

I am planning on doing that tonight...this whole ordeal has kinda reminded me that ive never done it on this car, i dont think thats the problem, but im going to do it anyways.

Theres only so many things it can be...Pretty much if i dont find something lodged in a vacuum line, thats the only other option....I was mostly curious about the wheel sensor thing, and if anyone thought that was possible with what ive described.

Thats def going to be my first checks....and find where the check valve is inline on this thing.

 

If it's wet and/or cool in the mornings, that's your problem right there.

How many miles on pads?

 

For a normal pedal to go very firm and require increased leg input means it has more to do with brake booster related issues. If it was just a lack of bite or fade in the pads, the pedal would feel the same or even get mushy, not significantly harder to press.

 

True. I was referring to his initial description of the wife putting on the brakes and the car not stopping.

 

20,000 miles or so...I absolutly love these pads, have never had an issue out of them. Of course, its more of a daily driven car, not a track ***** or anything.

Sorry if i didnt have that clear enough...She said it "felt fine, but didnt stop" Which meant the pedal didnt go to the floor. It still stopped up top...but had no power assist. But she doesnt even know what power assist or a brake booster is, so she didnt know to describe that to me. I found that bit out this morning when i got it to do it for myself.

Anyone know where the check valve is on these cars?

 

Fyi, the check valve is inside the rubber hose that goes from the intake manifold to over by the battery. Which is what's messed up on my car, if I can find a women that can unstick this valve by blowing or sucking it, I'm keeping her.