Brakes To The Mat!

[jnj]

Holy Cow! Has anyone ever had their brake pedal go to the mat for no reason at all? After an hour or so of stop and go traffic, I finally got to open it up. Approaching a stop sign (luckily) the pedal went all the way down. A pump or two brought it up. The next mile to the house, the pedal was weak and low, yet the brakes worked. Fluid level good (topped off a week ago) pad and rotors about 4 months old and no warning idiot lights. Stopped fine this morning with normal pedal pressure. Anybody wanna venture a guess, this one even has me stumped.

 

[Vettefan87]

It could very well be your master cylinder. If I were you I would bleed the brakes. I had a similar issue with mine and I bleed the breaks and the problem went away. Sometimes water will get into the lines and the brake fluid will heat up so much causing the water to evaporate, which then turns into air causing the brakes to be spongy. That is where I would start, it's a lot cheaper then a new master cylinder. I would not drive the car until you bleed the breaks, because if it is a master cylinder it could go out at any time and it might not come back either when you pump it. Good luck, keep us informed of what you find.


Justin

 

[taegdh]

You ahve to remember that brake fluid absorbs moisture from the air, and when you brakes get warmed up, the moisture turns to steam, in the lines and causes you to have NO pedal.


I've been advised, all through my automobile ownership experiences, change the brake fluid every three to five years. I usually don't keep cars that long, but on the few I have, I've done it when I had to change the pads / shoes. Gives me a sense of security, and it only takes an extra hour as long as my son can hear me over those confounded headphones.

 

[chevyaddict]

Definitely master cylinder..... that is what happens when they finally pucker out!

 

[berky2500]

I'm with Dawn, my master cylinder went out exactly the same way. One day fine, the next right to the floor. The next panic pump and it came back up. I actually drove gently for a week as it got progressively worse, it would work on the second or third pump. Replaced the master cylinder and bled out the entire system to correct.

 

[tntcorvette]

You have a MAP car so you either have a major vacume leak or the master cylinder is shot.

I forgot to hoop up a vacume line once and my break pedal went to the floor.

 

[vee93]

Holy Cow! Has anyone ever had their brake pedal go to the mat for no reason at all? After an hour or so of stop and go traffic, I finally got to open it up. Approaching a stop sign (luckily) the pedal went all the way down. A pump or two brought it up. The next mile to the house, the pedal was weak and low, yet the brakes worked. Fluid level good (topped off a week ago) pad and rotors about 4 months old and no warning idiot lights. Stopped fine this morning with normal pedal pressure. Anybody wanna venture a guess, this one even has me stumped.

Here's a my post from earlier this month!!!!

Like I said..., 1 thing then another!!!!

I'm hitting the accelerator and notice my brake light comes on. Ummmmm.... Just had new rotors and pads put on last year. Don't drive the Vette every minute of every day, so...
I noticed the pedal getting a little hard when applying the brakes, but I attributed that to the HOT weather here in Mississippi. And maybe I hadn't broken the brakes in good enough.
Well, the hard brake pedal and the brake light coming on not soon afterwards happened today (on a day not in the 90s too) and I drove the car home and parked it.
A few hours later I go out to move the Vette up into the driveway. Cranked it up, put my foot on the brake pedal to shift from park to reverse and the pedal goes all the way to the floorboard!!!! :eek Now THAT'LL give you a woman-looks-up-in-the-movie-and-sees-the-monster-moment!!!!!

Checked the master cylinder reservoir and the level was right on the money. Checked the wheel wells and side B of tires and saw no leakage spray. Lines looked good---gunky, but good as in no rips, tears or damage of any kind.

What's left? Air in the brakes lines? Still. Good thing I was in my driveway and not uhm..., 'autobahning' on the interstate,huh? YIKES!
Help please! Thanky!!!

 

[SKIP780]

just had this!!

my pedal went to the floor but lucklily it was in front of my driveway!!replaced the master cylinder. didnt fix it. i had a small leak on the left rear brake line.long story short---.where the line comes off the bosch abs unit behind the drivers seat and goes down and around then up to the l.r. brake it rotted out.the line next to it(to the r.r. brake) was about to go too. wont go into how to get at these lines here.spliced a new section of those 2 lines (steel line,double flare) and rerouted them out of the ABS well.whats my point? check that line and if you need info on the procedure contact me. ;

 

[dwestsr]

I had the same thing happen on my 86. I bought a new Master cylinder, but I have not put it in yet. I also needed new rotors and pads, so I replaced them first along with SS lines. Naturally , I had to bleed the brakes . Ever since the brakes were bled (actually flushed) , I have had excellent pedal and breaking. Looks like my problem was contaminated brake fluid. I'm keeping the MC just in case, but the brakes have been great for three months of daily driving.