I replaced the ABS / booster as a complete assembly 16 months ago and sent my original back as a core. So, this one had a previous life somewhere else. The wiring connector screws were nice and shiny but very tight.
Poll on total brake failure in 100 series (2 Viewers)
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For anyone that reads this yet another long post of I'm known for! 
Ideas, thought -----anyone???????????????????????????????
I see @Dwight S . So seller apparently, sent a used assembly without replacing motor's brushes or cleaning vent is my guess.
If you're not going to used that bad motor. I'd like it for testing, PM me please?
I could uses it, with another I have that was wet also and rubber falling apart also. I can compare with other dry ones I have.
The fact it's brake control wires & screws - shinny & tights - commutator were all good, is very helpful. Thanking for sharing that.
This is what I expected. It tells me normal resistance through wires, so as expected commutator good.
Just thinking out loud;
So why did brush wear out and not commutator. Well, brushes are a wear components of any motor. Wires good, is indicating resistance in wires normal, which commutator would be okay in most instances IMHO.
But could this be more than just high use and normal wear
I'm now I'm seeing another pattern. Maybe one we can look for during inspection, to give clues of early failure. This is the wetness in motor and rubber of armature falling apart. Could the fluid and muck have affected brush wear or armature adversely contributing to wear
The seal in the pump is not a pressure seal, it just an oil seal from what I can tell. So why are some motors wet with fluid from pump? My bet clogged air vent. Regardless the vent is design to allow air movement. I'm not and engineer. But past experience tough me high speed motor develop a vacuum, and can suck oil. The vent must be to equalize pressure IMHO. So I feel very strongly, we need this vent clear at all times or motor will suck brake fluid into itself.
But does it matter. Well, engineers of the motor put a drain passage between pump and motor. So they felt that some seepage at minimum could accrue. They would not want fluid sucked from brake system, so they vent the motor.
Could they also of had concerns, fluid getting in motor may adversely effect it
What it looks like, in your picture below and one I've here shown above. Is air vent blockage. With yours, I do not have the whole picture, in that vent starts in a rubber boot on out side of pump.
Your air vent @Dwight S
I don't "think" this would effect pressure in system, so run time test wouldn't be affected if I'm right. This seal is on low pressure side on pump. It would however at minimum with a clogged vent, cause fluid loss and likely some to get suck into motor.
Possible some seepage even with vent clear, if seal failing from age. Then we may see seepage but motor should be dry. This seal would be a rubber made for use with brake fluid, so not just ant seal can be used here.
As far as I can see; Toyota does not sell the seal. It does sell the motor and pump as one assembly.
I was trying to think of a test for the pump. So when we replace motor we can determine if a new pump a worthwhile investment. Only thing I think may work, is a pressure and flow test. But for this we need a good running motor. A beach test setup may be possible, but we need to build something. On vehicle would be more readily possible with standard brake pressure gauges. But how to we get flow rate. Measure flow at a rear bleeder. But with age the bleeder and the passage at caliper become restricted. So we need a system that has low mile and new caliper. We'd also need new pump and motor to compare with.. So chicken and egg store. They labor and time to pull motor and replace then test. May not be worth time and expense of gear, other than for research.
It still wouldn't tell much about seal. For that a static test may be helpful.
At minimum we need to clear this air vent.
Ideas, thought -----anyone???????????????????????????????
Ideas, thought -----anyone???????????????????????????????
I see @Dwight S . So seller apparently, sent a used assembly without replacing motor's brushes or cleaning vent is my guess.
If you're not going to used that bad motor. I'd like it for testing, PM me please?
I could uses it, with another I have that was wet also and rubber falling apart also. I can compare with other dry ones I have.
The fact it's brake control wires & screws - shinny & tights - commutator were all good, is very helpful. Thanking for sharing that
.This is what I expected. It tells me normal resistance through wires, so as expected commutator good.
Just thinking out loud;
So why did brush wear out and not commutator. Well, brushes are a wear components of any motor. Wires good, is indicating resistance in wires normal, which commutator would be okay in most instances IMHO.
But could this be more than just high use and normal wear
I'm now I'm seeing another pattern. Maybe one we can look for during inspection, to give clues of early failure. This is the wetness in motor and rubber of armature falling apart. Could the fluid and muck have affected brush wear or armature adversely contributing to wear
The seal in the pump is not a pressure seal, it just an oil seal from what I can tell. So why are some motors wet with fluid from pump? My bet clogged air vent. Regardless the vent is design to allow air movement. I'm not and engineer. But past experience tough me high speed motor develop a vacuum, and can suck oil. The vent must be to equalize pressure IMHO. So I feel very strongly, we need this vent clear at all times or motor will suck brake fluid into itself.
But does it matter. Well, engineers of the motor put a drain passage between pump and motor. So they felt that some seepage at minimum could accrue. They would not want fluid sucked from brake system, so they vent the motor.
Could they also of had concerns, fluid getting in motor may adversely effect it
What it looks like, in your picture below and one I've here shown above. Is air vent blockage. With yours, I do not have the whole picture, in that vent starts in a rubber boot on out side of pump.
Your air vent @Dwight S
I don't "think" this would effect pressure in system, so run time test wouldn't be affected if I'm right. This seal is on low pressure side on pump. It would however at minimum with a clogged vent, cause fluid loss and likely some to get suck into motor.
Possible some seepage even with vent clear, if seal failing from age. Then we may see seepage but motor should be dry. This seal would be a rubber made for use with brake fluid, so not just ant seal can be used here.
As far as I can see; Toyota does not sell the seal. It does sell the motor and pump as one assembly.
I was trying to think of a test for the pump. So when we replace motor we can determine if a new pump a worthwhile investment. Only thing I think may work, is a pressure and flow test. But for this we need a good running motor. A beach test setup may be possible, but we need to build something. On vehicle would be more readily possible with standard brake pressure gauges. But how to we get flow rate. Measure flow at a rear bleeder. But with age the bleeder and the passage at caliper become restricted. So we need a system that has low mile and new caliper. We'd also need new pump and motor to compare with.. So chicken and egg store. They labor and time to pull motor and replace then test. May not be worth time and expense of gear, other than for research.
It still wouldn't tell much about seal. For that a static test may be helpful.
At minimum we need to clear this air vent.
Ideas, thought -----anyone???????????????????????????????
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Need help please —
How loud is the warning buzzer? I was driving home from work today and a VERY loud buzzer sound came in the cabin. It was so loud it completely startled me and made me jump.
No lights came on and the brakes didn’t change from normal.
I was on the highway and driving in the right lane, ready to go into the shoulder to coast if the brakes failed. But the brakes worked fine and again, no lights, and that sound happened for a few seconds and then stopped and didn't come back.
There's an aftermarket head unit that was installed before I bought it — what was weird was that I was connected to it via bluetooth, and when that sound happened, I thought maybe it was the radio — I immediately turned the volume knob all the way down but the sound kept going at the same volume, so I thought that it couldn't be a stereo problem — but then, after the sound stopped, I was no longer connected to it via bluetooth.
I'm pretty concerned about it happening nonetheless — does this, as described, sound like the normal ABS warning buzzer? Or do you think it could be something different?
Thanks for the help
How loud is the warning buzzer? I was driving home from work today and a VERY loud buzzer sound came in the cabin. It was so loud it completely startled me and made me jump.
No lights came on and the brakes didn’t change from normal.
I was on the highway and driving in the right lane, ready to go into the shoulder to coast if the brakes failed. But the brakes worked fine and again, no lights, and that sound happened for a few seconds and then stopped and didn't come back.
There's an aftermarket head unit that was installed before I bought it — what was weird was that I was connected to it via bluetooth, and when that sound happened, I thought maybe it was the radio — I immediately turned the volume knob all the way down but the sound kept going at the same volume, so I thought that it couldn't be a stereo problem — but then, after the sound stopped, I was no longer connected to it via bluetooth.
I'm pretty concerned about it happening nonetheless — does this, as described, sound like the normal ABS warning buzzer? Or do you think it could be something different?
Thanks for the help
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Providing dash warning and indicator lights work. You would have seen those as well. Brake, ABS and/or others depending on year.
Note: When IG key inserted then turned to on, system goes through a test phase. At that moment you'd see all warring and indicator lights.
Note: When IG key inserted then turned to on, system goes through a test phase. At that moment you'd see all warring and indicator lights.
Yes, the dash lights [ABS & brake + everything else] do work (or at least aren't burnt out — they come on momentarily with everything else when starting the vehicle).
So hopefully it wasn't anything to do with the brake system. I'll post this elsewhere to see if someone knows why I had such a loud sound in the vehicle.
Just curious though — what does the ABS warning buzzer actually sound like? How loud is it and what type of sound does it make?
Thanks for the response
So hopefully it wasn't anything to do with the brake system. I'll post this elsewhere to see if someone knows why I had such a loud sound in the vehicle.
Just curious though — what does the ABS warning buzzer actually sound like? How loud is it and what type of sound does it make?
Thanks for the response
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High pitch whine/squeal. Not extremely loud but the pitch is such that you should hear it. If you monitor your gauges every few seconds like you should, the lights will get your attention and then the whine will confirm that there’s an issue. Once you get the alarm, you need to get off the road as braking will become an issue very quickly.
@2001LC, the vent hole wasn’t blocked up. Not saying there wasn’t some crud in the hole, but I could see through it. The picture was more an issue of camera angle. Not sure where the excess fluid was seeping in at. The armature was pretty well sealed to the top cap. I had to take a brass punch and tap the coupling ears to break it loose and separate it. I’m hopeful that I can take the motor to a local motor repair shop and see if they can refresh it for me. Would love to have a rebuilt one, just in case....
Great, thanks for the reply. From that explanation, this was a different issue then (no lights, brakes continued to work fine, the sound I heard was very loud and at a relatively low pitch). I have absolutely no idea what it could have been other than some bad wiring with the aftermarket head unit. But from reading this thread, I instinctively thought it could have been the brake sound and immediately slowed down and got to the right hand lane prepared for an emergency stop.
If the noise is coming from the center dashboard area, or passenger side, possibly the damper doors are responding. If it’s a “slide whistle” low to high, possibility the AC expansion valve.
The only time I've seen rubber insulator falling apart is in a wet motor. Brake fluid would do that. It's vent was clogged. Water would not. No other fluid in area.
The part of vent that I can't see in your pic, is on the pump. Do you have pictures of the pump and it's rubber boot?
A pic of the face of pump, gasket on or off like this? Would be revealing.
As a former 100 owner, this recent recall announcement from GM caught my eye.....
”General Motors is recalling almost 3.5 million vehicles because the brake assist system may fail, which could require more distance to stop, potentially leading to a crash.”
”General Motors is recalling almost 3.5 million vehicles because the brake assist system may fail, which could require more distance to stop, potentially leading to a crash.”
I just found out that my SA1 Circuit needs to be replaced. Seems like it's a costly repair at around $3000. So far my brakes work but you can tell something is wrong. I hope this is a job I can DIY since this is more or less a project truck.
I did one, that is, if it is you ABS (box box) unit on side of MASTER. It had a corroded brake control wire. I'd be very interested to know if your wire corroded. Dealer quoted $5,500 to my client. I think we got it done for $500.
Just had a curious wheel speed sensor code pop up. History is that I’ve had brake failure twice. The first was the original brake pump from my 98 with 160miles. Swapped out the master for a junk yard LX. That pump only lasted 8 months, so I now replaced all brake lines, junctions and put a new pump on. Seems to be working very well now.
Issue is that before each failure, when pulling codes I got wheel speed sensor codes for front left and rear right wheels. After I change out the master cylinder parts though the speed sensor codes go away. I have the speed sensors now but am wondering if this is a real code or one that could just be saved in the system from a while ago or perhaps is somehow linked to a failing brake system. Any thoughts?
Issue is that before each failure, when pulling codes I got wheel speed sensor codes for front left and rear right wheels. After I change out the master cylinder parts though the speed sensor codes go away. I have the speed sensors now but am wondering if this is a real code or one that could just be saved in the system from a while ago or perhaps is somehow linked to a failing brake system. Any thoughts?
Had the same thing happen repeatedly after changing the MC parts. The anti-lock brakes would even kick in when braking normally.
Had to change the front speed sensors. After checking with another forum member, I swapped out for cheaper Chinese/eBay (link and link2 - prices have jumped 10 -15 bucks!) sensors rather than OEM$ and everything has been great.
Friend showed me how to remove (drill out) the sensors and replace them from the rear without taking off the brakes. Saved me 4hrs!
Curious if that’s what I’m experiencing. How did you know the abs was activating? Was it from vibration in the brake pedal?
Currently I’m annoyed that I feel vibrations in the pedal but as far as I can tell the vibration is tied to when the motor runs. Is that normal?? I’m running by Toyota today to see if the code came back after I cleared it.
Had the truck scanned today— no brake lights or ABS on, but all these show as “current”
C0278
C0205
C0210
C1251
C1252
C1253
C1254
C1256
Just for reference, those are
Open ABS solenoid relay
Front left speed sensor
Rear right speed sensor
Open in pump motor circuit
Brake Booster Pump Motor on Time Abnormally Long
Hydro Booster Pump Motor Relay Malfunction
Pressure Switch Circuit
Accumulator Low Pressure
Open ABS solenoid relay
Front left speed sensor
Rear right speed sensor
Open in pump motor circuit
Brake Booster Pump Motor on Time Abnormally Long
Hydro Booster Pump Motor Relay Malfunction
Pressure Switch Circuit
Accumulator Low Pressure
This is concerning "Brake Booster Pump Motor on Time Abnormally Long". We never want to see this. Motor running longer than 2 minutes cause excessive wear.
This "Open ABS solenoid relay" could be key.
What is junction? "so I now replaced all brake lines, junctions and put a new pump motor.
Was that a new OEM motor & pump and with new brake control wire?
This "Open ABS solenoid relay" could be key.
What is junction? "so I now replaced all brake lines, junctions and put a new pump motor.
Was that a new OEM motor & pump and with new brake control wire?
