Slammed brakes, pedal sank to floor

[phillipeino]

The other day I was in a situation where I needed to hit the brakes, hard. My 4runner slowed down then the brake pedal sank to the floor and was no longer braking. I quickly lifted off the brake and then reapplied the brake. This time the 4runner slowed as normal. All of this happened in a couple of seconds. If I didn't pump the brake I would've ran into the car in front of me.

Anyone know what happened here? Anything I should do or look for so this doesn't happen again?

 

[BlackWorksInc]

Huh... that's very odd. Usually when you panic brake in a 4Runner those brakes STOP, the force sensor notices the extra force and goes into "OMFG STOP THE TRUCK" mode. It should hold up for a good few seconds until the system lets of the solenoids to prevent overheating.

From the sound of it, it sounds like pressure bled off way too quickly, have you had any braking issues and/or previous noises/symptoms prior to this?

-Year/Trim?
-Engine/drivetrain?
-Mileage of the vehicle?

 

[phillipeino]

Huh... that's very odd. Usually when you panic brake in a 4Runner those brakes STOP, the force sensor notices the extra force and goes into "OMFG STOP THE TRUCK" mode. It should hold up for a good few seconds until the system lets of the solenoids to prevent overheating.

From the sound of it, it sounds like pressure bled off way too quickly, have you had any braking issues and/or previous noises/symptoms prior to this?

-Year/Trim?
-Engine/drivetrain?
-Mileage of the vehicle?

The only other issue I had with my brakes was during the summer the brake pedal felt softer. When it's colder out the brake pedal is pretty firm

2007 4runner Sport v6
91miles

 

[BlackWorksInc]

Hmm... Have you had your brake fluid serviced at all?

 

[earthrealm]

subbed

 

[parboy]

Last time I was at the dealer they did
#TC-14-032 TSB
TOYOTA: ON SOME VEHICLES, INFORMATION BEING SENT OUT REGARDING INSTALLATION OF SMART STOP TECHNOLOGY. MODEL YEARS 2003-2010 COROLLA, COROLLA MATRIX, LAND CRUISER, HIGHLANDER RAV4, 4RUNNER, TUNDRA. *PE

check to see if it was done on yours while they look it over

 

[wnelax04sr5]

leak in the lines? a pinhole may cause that symptom under heavy pressure, but unlikely that the pedal would go to the floor

 

[emoore924]

Bad MC?

 

[drewm]

Hmm... Have you had your brake fluid serviced at all?

Agreed, cars need a brake bleed job every 50k or so, otherwise you get moisture in the lines which boils and turns to a gas during heavy braking, and a gas is not a good hydraulic fluid. If your pedal ever feels soft, get a bleed job immediately.