2008 sr5 4wd weird brake issue

Civiceg94

Civiceg94

New member
Ok. Hopefully i could explain it well. But if you hopeful people are confused feel free to ask me any question. I been having weird brake issue since the day i bought the runner last april. And today i got fed up and feeling unsafe to even slam on my brakes. This morning i was going 90 mph. I stepped on the brakes to start slowing down. The brake pedal got hard and abs started to kick. Like if my tires were skidding. Smh. The runner didnt feel like it would stop in time. Good thing i had tons of space. Theirs other times where am going 50 maybe 60. Hit the brakes on uneven surface and the pedal would get soft and abs would start kicking in its really unsafe. The only way ill get to stop normal if ill ease into the braking or if am going bumper to bumper traffic. Their was one time a car stop in the middle of the road. The car in front of me avoided the stopped car and i didnt notice till late. I smashed the brakes the jeep didnt stop so i had to hit the throttle and got no respond from the throttle also i was a sitting duck What the fu********* is going on with the runner i would hate to sell cause of this issue. I really love this toyota. Am checking here. To see whats said before i bring it to the dealer
 
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lets start with the easy stuff:

what cond are the brakes?
is the fluid in good shape?
was the fluid ever changed?
how is the master cylinder and brake booster?
how are the brake hoses?
any abs codes?

you mention two different braking situations. both sound like two different issues.

soft brakes- failing master cylinder, low fluid, air in lines, pourous brake system etc..

hard brakes- usually means a bad brake booster or a bad vacuum source

this could also be caused by a bad abs sensor. my GMC did the same thing except it was under 10mph.

how many miles on your 4runner?
 
Civiceg94 said:
Their was one time a car stop in the middle of the road. The car in front of me avoided the stopped car and i didnt notice till late. I smashed the brakes the jeep didnt stop so i had to hit the throttle and got no respond from the throttle also i was a sitting duck ��
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This suggests that your VSC is being activated somehow and cutting throttle response. Any warning lights on the dash? I think you need to get the ABS and VSC diagnosed. Probably a dealer trip is in order.

You might try searching "zero point calibration" on this forum and going through that process.
 
inscarguy said:
lets start with the easy stuff:

what cond are the brakes? Brakes are new replaced them when i bought the runner
is the fluid in good shape? Fluid is nice and clear. Which i found weird lol.
was the fluid ever changed? Most likely
how is the master cylinder and brake booster? Looks new doesnt look old or beat up.
how are the brake hoses? Brakes are new replaced them with ss lines.
any abs codes? No codes showing.

you mention two different braking situations. both sound like two different issues.

soft brakes- failing master cylinder, low fluid, air in lines, pourous brake system etc..

hard brakes- usually means a bad brake booster or a bad vacuum source. FROM MY UNDERSTANDING THEY DONT HAVE VACUUM SOURCE TO BRAKES. SINCE THEY ARE A HYDRO BOOSTER

this could also be caused by a bad abs sensor. my GMC did the same thing except it was under 10mph.

how many miles on your 4runner?ITS 155,000 and counting
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I put the answer in the question hopefully it comes out. There
 
Civiceg94 said:
I put the answer in the question hopefully it comes out. There
Click to expand...
crap my bad I forgot the 4runners are hydraulic assist.

maybe the unit is failing?

I know there is some sort of procedure that if you pump the brakes like 20-40 times it does something to the braking system. I forget how many times. maybe someone who knows this can chime in.
 
RonJR said:
This suggests that your VSC is being activated somehow and cutting throttle response. Any warning lights on the dash? I think you need to get the ABS and VSC diagnosed. Probably a dealer trip is in order.

You might try searching "zero point calibration" on this forum and going through that process.
Click to expand...

I havent seen one for the 06-09 zero point calibration all i seen i think was for the 03-05. Maybe someone could shed some light on that
 
inscarguy said:
crap my bad I forgot the 4runners are hydraulic assist.

maybe the unit is failing?

I know there is some sort of procedure that if you pump the brakes like 20-40 times it does something to the braking system. I forget how many times. maybe someone who knows this can chime in.
Click to expand...

The unit looks new thats the funny part like if they repaired it before. Yeah hopefully someone could explain about that pumping the brakes.
 
I drove a 4runner recently which had been wrecked that had a similar issue. Brake lines were replaced and I could see some fluid had leaked out. Maybe bleed the brakes? Flush entire system, starting from caliper closest to the master cylinder and end at the farthest. It's a cheap and easy job. Post any results when you find the cause.

-al
 
alhang said:
I drove a 4runner recently which had been wrecked that had a similar issue. Brake lines were replaced and I could see some fluid had leaked out. Maybe bleed the brakes? Flush entire system, starting from caliper closest to the master cylinder and end at the farthest. It's a cheap and easy job. Post any results when you find the cause.

-al
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That what i ended up doing. When i put in the new front and rear ss lines ran threw a brand new bottle.
 
from 2006 FSM

7Y7RQjA.jpg
 
I think i perform it correctly not sure. The first step and last step was confusing. The first step i did it but i couldnt check if warning lights came up. When i finished their was none. So I continued to the next step. It was blinking for more then 2 seconds and never stopped. So did i do it correctly ?
 
The plug is oriented upside down from the picture FYI
Do bold steps 2&3...use a paper clip
 
Last edited:
Tires. Check them. It could be your tires. Easy enough to check without going crazy. the need for zero point calibration shows because you have VSC OFF and TRAC OFF lights showing on the dash. Other than that a failing master cylinder or old fluid can cause mushy brakes. Also these vehicles dont stop on a dime. If you have the smaller calipers and 17"+ wheels they will account for slower braking.
 
Hyaline said:
Tires. Check them. It could be your tires. Easy enough to check without going crazy. the need for zero point calibration shows because you have VSC OFF and TRAC OFF lights showing on the dash. Other than that a failing master cylinder or old fluid can cause mushy brakes. Also these vehicles dont stop on a dime. If you have the smaller calipers and 17"+ wheels they will account for slower braking.
Click to expand...

I dont have any lights showing.
 
Could it be a seized caliper? During acceleration the wheel speed would be these same but under braking the wheel speed would be inconsistent causing the ABS to kick in when it didn't need to? Do all your pads look normal?
 
alhang said:
Could it be a seized caliper? During acceleration the wheel speed would be these same but under braking the wheel speed would be inconsistent causing the ABS to kick in when it didn't need to? Do all your pads look normal?
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Everything is normal. Its not on a constant basis that the abs kicks in and and ill either get a hard pedal or a soft pedal
 
The OBD-II plug is shaped like it is in the drawing. Mine is upside down from the drawing. I have a 2008 SR5 4WD
 
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