So glade everyone is okay. Fortunately that always seems the case!
Total brake failure happened today, 2006 LX470 with 175k miles. Luckily it was just in a parking lot, but we were fully loaded ready to go camping. Good thing you didn't happen 4 hours later or we would have been a LONG way from help.
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I'd be very interested in what you find is cause.
Also when you say total brake failure what happen, in detail please? What first alerted you? Then what happened?
Typically sudden brake failure, where pedal goes to the floor. Is booster motor failure. Alarm and dash lights go on and we get 1, 2 or 3 strokes (each weakening) before pedal goes to the floor after motor failure. This is due to loss of booster pressure, because booster motor failed to run. Motor failure!
There is also certain very rare condition where no power (12V) gets to the motor. So motor is good, just no current to run it.
The accumulator can fail but usually a slow death.
If a brake fluid leak developed and fluid is lost, the same thing happens, in we've no pressure. We can have a line leak and still have brake in other three wheels. I've seen where reservoir has totally emptied. No brake fluid no brakes. But here alarm should sound very early on, Just as level drops below low line. Failure happens when empty.
A small leak will result in pressure loss. This will activate booster motor excessively. Someone that rides there brake or a tail gate-er or heavy stop and go traffic using brakes often. This all uses motor more than HWY miles of a proper service brake system. So mileage is not a good indicator of life of motor.
I'm most interested in the wire from bottom of your ABS (black unit on side of brake master) that runs to the booster motor. I find ~30% of these wires corroded. In all failure I've repair, the wire was corroded. I've a theory, that the wire being corroded is increasing resistance. This a non reusable wire according to factory. This 8 " two wire harness list for $170, I kid you not. It's because it's a resistance wire. My theory is, this is leading to early failure of the motor from increase in resistance. In some cases, wire may be responsible, for failure of ABS unit, which current flows through.
My interest in this is in trying to inspect for failure before it happens. In that, the corroded wires may mean we need to replace wire and rebuild motor when we find this. The more cases I find with failure and a corroded wire associated to it, the stronger my theory becomes.
So please report back with detail and pictures.
Here some pictures of the wire corroded. In ~30 % of 100 I inspect, I found the brake fluid reservoir was over filled. Shop top brake reservoir without reading instruction embossed on reservoir on how. I suspect brake fluid gets into the wires boot, attracting moisture.
1999 w/150Kmiles from CO
2007 w/100K from GA/TX. Inspection with mirror.
07 after wire & screw clean up. You can see reservoir if you look close to orient yourselves as to wires location.
2005 w/85k miles from SoCA
I also just inspected a 2000 LX very clean with 200K miles. It also had corrosion on wires.
I've a 2000LX w/350K miles and some undercarriage rust and bolt rust in engine compartment, as came from CN and Boston. Wires are not corroded. So it does not seem to matter the climate the rig was in or the age or the mileage. It also does not matter if engine washed. As my 01 w/160K miles was washed so much over 13 years you could eat off the engine. So why are some corroding! Brake fluid is my theory from over filling. Book stated do not over fill.
