Yet another brake thread...sorry folks (1 Viewer)

[JunkCrzr89]

Toyota replaced a Tacoma frame for a buddy at 230k when it had rusted through. I don't see how an unnanounced failure of a braking system would be less dangerous than a perforated frame.

They recalled hundreds of thousands of Takata airbags for failures as well.

Most likely, this hasn't been addressed because folks have fixed it without reporting it, and/or Toyota made few enough 100s that they see it as a reasonable risk.

The same booster assembly on 100s was also used on 4runners, Tacomas, and GX.

The Taco frame replacements were the result of a class action lawsuit, so not comparable to the booster assembly issues we have...yet.

 

[flintknapper]

Maybe you're right, but I had never heard about brakes failing like this on a car until I started kicking around here. Maybe they do, but I personally had never heard of it before.

I think it's important to qualify the terms 'brake failure' and 'complete brake failure' as are often used here.

In my case (and I suspect in most others) I did not experience complete brake failure (meaning I had NO brakes). I DID lose 'boosted brake' performance (leaving me with basically manual brakes). By applying enough pedal pressure I was still able to stop the vehicle.

However....in cases where a person ALSO has been ignoring a spongy pedal/sticking pedal/double pedal pump (because of master cylinder leak-by) you might indeed experience something close to 'no brakes'.

Another consideration....IF you don't have the leg strength to press really hard on the brake pedal....then for all practical purposes you 'have no brakes'. Of course... this applies to conventional Vacuum Booster failures as well.

I wasn't driving (in traffic) when mine failed....so I haven't experienced the unsettling feeling it is SURE to create. It can't be fun trying to stop as large and heavy a vehicle as these are in a panic situation. As a 'community' we can encourage and promote the inspection of the system on a regular basis. The same as we do with 'heater Tees' and few other items.

 

[AlpineAccess]

The same booster assembly on 100s was also used on 4runners, Tacomas, and GX.

The Taco frame replacements were the result of a class action lawsuit, so not comparable to the booster assembly issues we have...yet.

Good context on the different models, something may come from it, if people report it.

 

[427060]

Incorrect.
The electric pump pressurizes brake fluid, the accumulator is for high pressure brake fluid.

Neat! Thank you. Have been trying to wrap my head around it.

 

[white_lx]

Maybe you're right, but I had never heard about brakes failing like this on a car until I started kicking around here. Maybe they do, but I personally had never heard of it before.

Mercedes recalled their vehicles for a similar issue: Sensotronic Brake Control - Wikipedia

"In a letter - only to US customers - dated August 2018 a warranty addendum was sent extending coverage for 25 years and unlimited miles on the following SBC components.

• Hydraulic control unit
• Hydraulic Pump
• Pressure Reservoir
• Brake Operating Unit
• Front and Rear wheel speed sensors
• Brake lamp switch
• Yaw Rate Sensor"

All Toyota hybrid models have a similar set-up as the 100 series (no vacuum during hybrid EV mode, although an electric vacuum pump might have been a better solution). 4-Runners, Lexus LS/GX have a similar setup as well.

 

[Skidoo]

Neat! Thank you. Have been trying to wrap my head around it.

I wish there was more documentation on the braking system so we didn't have to guess.
It has to have some failsafe's. Has anyone dug deeper into the fail safe modes?
We know if the pump fails and the accumulator is charged it has enough high pressure fluid for up to 40 pedal depressions, after which braking is very difficult.
I am guessing if the ABS controller fails or loses power you still have some form of braking, at least I hope.
So it must have some hydraulically controlled valving to go with the electronically controlled ABS/ATRAC/VSC stuff.