Complete Brake Failure -- Thanks Toyota!
- Thread starter dpr422
- Start date
I take it you've never seen a master brake cylinder fail?? Master brake cylinder fails and you won't have any brakes at all.
But I do think this is neglect on the OP. When was the last time you had the fluid changed??? You gave us the mileage...but what year is this vehicle???
Atlanta_man
New member
I'd like to hear the rest of the story. Beginning 2 minutes after putting the truck in P.
Drive it home ?
Have it towed ?
Mechanic able to replicate the problem ? if so - what part hard-failed ?
Drive it home ?
Have it towed ?
Mechanic able to replicate the problem ? if so - what part hard-failed ?
combatmedic
Banned
Gerdo
New member
I wouldn't blame Toyota.
A little background on ABS. It pulses the brakes on and off. Of course it the ABS failed, you could totally lose the brakes. You said that you have been having issues with the ABS engaging in conditions that don't seem to require it. This is when the bad part of the ABS system should have been replaced. Luckily your daughter was quick to think and got the vehicle stopped.
I do feel that you may have been misinformed by the repair personnel.
Replace the part and enjoy the vehicle for many more years.
A little background on ABS. It pulses the brakes on and off. Of course it the ABS failed, you could totally lose the brakes. You said that you have been having issues with the ABS engaging in conditions that don't seem to require it. This is when the bad part of the ABS system should have been replaced. Luckily your daughter was quick to think and got the vehicle stopped.
I do feel that you may have been misinformed by the repair personnel.
Replace the part and enjoy the vehicle for many more years.
bluemarlin04
New member
I have, but I've never ever seen one just stop working (very unlikely, it would mean every seal and piston totally broke, complete destruction of the part). Usually, the pressure will fade over time and it will be obvious you're brakes are not working. It will not go on and off like a switch.
How does ABS failing kill brakes? It is an active, not a passive system. Rip a ABS speed sensor out, and the system can't work and will pop a light, but your brakes continue to work.
Pull the ABS fuse, again, a light but brakes continue to work? The ABS system does not normally have any control of the brakes and instead must "grab" hold of the system in one of the whatever coded scenarios. If the ABS system goes kaput, it just won't engage. That doesn't mean it prevent the physical fluid pressure from pushing the piston out, to grab the brake. It may be actuated by an electronic helper, but at its core, your brakes are a purely fluid system.
I guess I find the thought that a wonky ABS killing your brakes horrifying as ABS systems have always been less than awesome in terms of dependability.
Pull the ABS fuse, again, a light but brakes continue to work? The ABS system does not normally have any control of the brakes and instead must "grab" hold of the system in one of the whatever coded scenarios. If the ABS system goes kaput, it just won't engage. That doesn't mean it prevent the physical fluid pressure from pushing the piston out, to grab the brake. It may be actuated by an electronic helper, but at its core, your brakes are a purely fluid system.
I guess I find the thought that a wonky ABS killing your brakes horrifying as ABS systems have always been less than awesome in terms of dependability.
Here is the update... and yes, why I am mad at both Toyota and the dealership.
Yes, the car (2005 4R Sport, 65k miles) was towed to the dealer.
The Master Brake Cylinder did fail and there was no way to stop the car without using the parking brake (best option) or taking it out of D. The brakes went completely out. She hit the brake and the pedal went to the floor with zero resistance. I was in the car - the entire dash lit up, and the car was closing in the student driver in front of my daughter. Opposed to hitting another car, we just needed to stop the car! I could have cared less about the tranny or parking brake - I was just glad she did something instead of nothing! Again, thankfully this did not happen on the open road - stop sign, red light, school crossing, highway -- the list goes on!!!!!!
So, why am I mad ? We did not blow this off. We had heard an oscillating sound from the engine compartment for 2 years. Every time we told the dealer about it and they just said it was nothing to worry about... the car was just getting older. I thought is was the AC. It was not until 4 months ago that they noticed an error code on the ABS systems, but said this was not related to the braking system. I did call Toyota Customer Care and they said the same thing the dealer told me. The car was safe to drive - if the ABS fails, the brakes will work fine. I should mention that the ABS was still working fine so I had no reason to believe this car was unsafe - I thought both the dealer and Toyota CC had given me sound advice and that I would just have the ABS fixed if and when it failed.
With this said, if I was told this car was unsafe or there was a risk the brakes could completely fail, I would have fixed or traded it in without giving it a second thought.
Net/net is that this was a bad situation that could have been worse -- much worse regardless of the driver behind the wheel.
Yes, the car (2005 4R Sport, 65k miles) was towed to the dealer.
The Master Brake Cylinder did fail and there was no way to stop the car without using the parking brake (best option) or taking it out of D. The brakes went completely out. She hit the brake and the pedal went to the floor with zero resistance. I was in the car - the entire dash lit up, and the car was closing in the student driver in front of my daughter. Opposed to hitting another car, we just needed to stop the car! I could have cared less about the tranny or parking brake - I was just glad she did something instead of nothing! Again, thankfully this did not happen on the open road - stop sign, red light, school crossing, highway -- the list goes on!!!!!!
So, why am I mad ? We did not blow this off. We had heard an oscillating sound from the engine compartment for 2 years. Every time we told the dealer about it and they just said it was nothing to worry about... the car was just getting older. I thought is was the AC. It was not until 4 months ago that they noticed an error code on the ABS systems, but said this was not related to the braking system. I did call Toyota Customer Care and they said the same thing the dealer told me. The car was safe to drive - if the ABS fails, the brakes will work fine. I should mention that the ABS was still working fine so I had no reason to believe this car was unsafe - I thought both the dealer and Toyota CC had given me sound advice and that I would just have the ABS fixed if and when it failed.
With this said, if I was told this car was unsafe or there was a risk the brakes could completely fail, I would have fixed or traded it in without giving it a second thought.
Net/net is that this was a bad situation that could have been worse -- much worse regardless of the driver behind the wheel.
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This car has been in for every major and incremental service, including fluid changes since is was purchased in 2005. The brake fluid was changed less than 1 year ago and two years before that... Yes, they said this is unusual- only seen this happen with a few 4Rs.
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Unlike you, I am not a Toyota Master Mechanic... we suspected the AC... We had no idea it was the braking system to include ABS... Even after they suspected the ABS no red flag was given..
Gerdo
New member
ABS pulses the brakes on and off once the system has sensed wheel lock. It is conceivable that the ABS locks in an open position and totally disable the brakes.
It doesn't sound like that is the issue in this case.
mrrab
New member
Hmm, well I don't know if I have the same sound you're discribing, but when I turn the car to the "On" position I hear this "cycling" noise. Pretty sure it's the ABS system cycling through it's complex system, which I just learned about.
Why can't they just keep cars simple. I don't need all this traction control, vehicle stability BS!!!
I'm not part of the "general poplation"
Why can't they just keep cars simple. I don't need all this traction control, vehicle stability BS!!!
I'm not part of the "general poplation"
Exactly the same sound... What I was told by the dealer where the car was towed (not the same dealer that did not diagnose the problem for over two years) is that this sound was from the Master Brake Cylinder trying to establish a vacuum. It will keep cycling until it fails, which it did in my case.
scottm
New member
I'd like to know what kind of master cyl fail caused this, pictures maybe? All modern vehicles have double master cylinders fed by two sections of reservoir, each operating brakes on two wheels. This would have to be something like the casting splitting open, or the entire unit breaking free from the firewall, or the reservoir popping off. Extremely unlikely, but not impossible.
I should find out this week, but there were no leaks or anything to suspect the major failure that occurred. I watched my kid slam both feet on the brake trying to stop the car. It did not slow down. The pedal went to the floor with zero resistance.
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You took it in for a noise and they changed the thermostat? That is some funny **** right there.
