Hard Brake Pedal on or off engine barely have brake when its drive from stop.

[makokak]

Good Afternoon everyone,

My vehicle: 2000 4runner V6 4X2

recent change/upgrade: TBU in 2018.

oh oh oh my wife drove it for 3-4 miles while hand brake is engage.

Now: brake pedal is hard on or off engine, barely have brake when put to drive.

test done: remove the vacuum hose from intake manifold, vacuum is pretty strong, remove from the booster vacuum is pretty strong no leak along the vacuum hose.

what else could it possibly be? or any more test i could done?

 

[RandyBobandy]

Probably the booster, I don’t think driving with the e brake on would cause this, I’d go to the junkyard and get a booster and see if that fixes it

 

[makokak]

is it worth trying to see if it is the check valve, at least less than 10 buck from oreily's?

 

[HiLife]

With the engine running to charge the vacuum booster. And then turning the engine off, you should have one or two vacuum assist pushes on the brake pedal if the brake booster and check valve are holding vacuum.

 

[FunBobby]

Mine did this last year, it was the booster

 

[19963.4lsr5]

My check valve caused this on the 96


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[HiLife]

On mines, it was the booster that failed on the 4runner. It made driving interesting, made sure I had plenty room to brake.
My check valve was good but I replaced it anyway. Kept the older one as a spare.
I learned to drive on a 64 Malibu, manual drum brakes all 4 corners. That was a fun car to brake to a short stop.

 

[19963.4lsr5]

On mines, it was the booster that failed on the 4runner. It made driving interesting, made sure I had plenty room to brake.
My check valve was good but I replaced it anyway. Kept the older one as a spare.
I learned to drive on a 64 Malibu, manual drum brakes all 4 corners. That was a fun car to brake to a short stop.

Yea, my 68 Roadrunner was guess a lane on a hard stops.


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[makokak]

Thank you guys for the reply.

i removed the check valve and mimic a vacuum and it does let the vacuum in but not going back in, i think thats how it should be.

i have new finding; while the engine is running i pressed the pedal probably a good 2-3" down and i can hear a hissing sound. does that confirmed my booster gone bad?

 

[19963.4lsr5]

Thank you guys for the reply.

i removed the check valve and mimic a vacuum and it does let the vacuum in but not going back in, i think thats how it should be.

i have new finding; while the engine is running i pressed the pedal probably a good 2-3" down and i can hear a hissing sound. does that confirmed my booster gone bad?

Buy the check valve and see if it solves your problem. If it doesn’t buy the brake booster and install your new check valve and your rig will rust out before you need to touch those two items again.


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[Doctorman]

probably the booster...
do a nice brake fluid flush , if the pads are good you should be good

 

[Twisted Sid]

Same issue I had a few years ago. Mine was the booster. I put on a used OEM one from a buddy's parts truck with half the miles mine had at the time and it was fixed.
Didn't have to open the brake system or anything. Just unbolted the master from the booster and moved it out of the way and the booster was a few bolts and it was off. Took like an hour.

 

[mtbtim]

I also agree with the others that said it's most likely a bad brake booster. The video below was shot on a FZJ80 Land Cruiser but a lot of the information we share could help you swapping out the brake booster on your 3rd Gen. Good Luck!

<iframe width="560" height="315" src="https://www.youtube.com/embed/KqugF6hLAMY" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

 

[TucsonMike]

My 2000 and my friends 1998 both had a hissing noise and in both cases it was a bad booster. We both got the seiko booster which I believe is OEM . They r expensive $300 when I got mine several years ago. I bet your issue is the booster as well.

Good luck

MikeM

 

[phattyduck]

Yea, my 68 Roadrunner was guess a lane on a hard stops. k

I went through a couple intersections sideways locked up (in the rain, normally) in my '67 Ford truck with manual 4-wheel drums. The worst was driving after soccer practice with tired legs...

-Charlie

 

[nissanh]

The diaphragm hardly fails on a Toyota booster. I found only once a seal at the push rod connected to the brake master pump has failed. I found a replacement and all is good.

 

[makokak]

im planning to make it a weekend project. thank you all