One episode of not being able to push brake pedal to the floor

I have an '03 Toyota Matrix with 98 thousand miles on it. A week ago Friday was the 1st or 2nd day of sub zero weather here. I walk to work so don’t use my car all day. That night I went out doing errands at around 8PM. After about 15-20 minutes driving in my car I was on a side road doing about 40, I stepped on the brakes and couldn’t get the pedal to push down and the brakes wouldn’t work to stop the car. I pressed two more times with my foot and the same thing happened. The pedal wouldn’t press down and the car had no braking action. I let the car slow with my foot off the gas, tried it again and the brake worked like normal. The foot pedal pressed down and the brakes worked. I was near the store I was going to shop at, so I parked and went in for about 20 minutes, then drove home with no problem. I took it in to the Toyota dealer and they could find nothing wrong with the brakes. I later took it in to another place and they also could find nothing wrong. I have been using the car sparingly as I am a little nervous, but things are working like normal. Do you know what the problem could be? Should I be nervous?


If the pedal was rock hard, you have a vacuum problem

Vacuum brake booster
The hose going to the booster
An engine vacuum problem . . . not enough vacuum going to the booster

The problem might also be with the vacuum brake booster check valve.


OP metioned inop brakes. A vacuum failure would still allow non-assisted brake function…just more effort.

Maybe he’s got a coffee mug or something rolling around…

I’d recommend seeing how long vacuum is held after turning engine off.

A bit of a stretch here, but is it possible that the brake fluid has absorbed so much water that some ice formed somewhere in the system and a brake flush would be in order here?

I believe Keith is correct. Brake fluid absorbs water over time and IMO the fluid froze.
Have a shop flush the system with new brake fluid.

It’s possible also that water splashed up and ice formed on something in the brake system which is normally supposed to move freely, but got frozen in place b/c it is so cold, like the caliper slides, which locked the brakes up. I’ve lived in a fairly cold climate before, never seen or heard of that happening though. The truck I drove then (& now) has drum brakes. The moving parts of disc brakes are more exposed to water splashes, maybe that has something to do with it.

OP should of course – until this is resolved – test the brakes several times upon leaving home, and to immediately return to driveway and park the car for the day if they aren’t working 100%. Besides the above ideas, esp the one to have a mechanic verify the brake booster function is working correctly, the OP should try the emergency brake, see if that stops the car when this happens. Could provide a clue at least. And as mentioned above, make sure there is nothing obstructing the brake pedal.

A vacuum issue wouldn’t surprise me. Unless someone already knows what it feels like to drive without power assist, then feeling could easily be interpreted as “no braking” - when it was really just requiring a whole lot more force than normal. I also wouldn’t rule out the coffee cup rolling around though.

Are you sure you didn’t have your left foot under the pedal?