Complete Brake Failure -- Thanks Toyota!

[BlackWorksInc]

One could argue that the fail-safe mode isn't safe enough. Maybe the brake booster could warn you sooner if it is failing, such as if it detects a slow reserve pressure leak, or if the motor starts running at an unusual temperature or something. It could keep you from driving the car if it detects any problem in the brake system, but I'm sure that would generate complaints. Or maybe it could deploy emergency parachutes out the trunk?
...

That's what makes his particular case so odd to me. The units usually do set a DTC or even start sounding odd before they ever get that bad.

If you look at the majority of Master Cylinder failures you'll see there's usually a DTC for pressure, voltage, and/or some other failure. If there isn't a DTC there's a complaint of excessive noise (buzzing, ect.) or the brakes starting to feel weird (from the pump not being strong enough and/or the accumulator bleeding off pressure.) The OP's failure is very very odd in how quickly and completely it occurred.

 

[Barefoot]

I have never, ever, heard one story of the vacuum assist failing.

You have now. It happened to me. I still was able to stop by pushing hard on the brakes. At the time I was more bothered by the big cloud of white smoke coming out the back of the car when brake fluid got sucked into the intake because of the failed diaphragm.

 

[nevada]

You have now. It happened to me. I still was able to stop by pushing hard on the brakes. At the time I was more bothered by the big cloud of white smoke coming out the back of the car when brake fluid got sucked into the intake because of the failed diaphragm.

youch. the mc must have been leaking also. there is no fluid transfer between the mc and booster under normal operation.



ive changed more than a few failed vacuum boosters. ive driven many cars with "manual" brakes. they are hard to stop, but not impossible.
people now a days are big pussies....

 

[earthrealm]

yup, add me to the list........buzzing sound for about 2yrs, then bam today shit craps out!.

SO sadly today @ 130200 miles, my brake system/MC failed......just came back from a 20mile round trip during my luch break, car was ok, parked the car...got back to work, 3 hrs later i enter the truck to drive home, as soon as i start the car and engage gear, i hear a high pitched warning sound and all the lights on my dash light up, brakes rare pretty useless, gotta stomp on them with all my might b4 the truck stops.....

i have had the buzzing/pulsing brake pedal issue for 2 yrs now, so i guess it has finally crapped out, dont have the $$$$$s for a new MC/brake system, so i intend to pick a used unit from ebay, and go from there...........need to figure out how to manually bleed the brakes after swapping out the bad unit [MENTION=66389]BlackWorksInc[/MENTION] i guess anyone with a similar pulsing brake issue, shoud prep for the day it craps out

 

[BlackWorksInc]

yup, add me to the list........buzzing sound for about 2yrs, then bam today shit craps out!.

SO sadly today @ 130200 miles, my brake system/MC failed......just came back from a 20mile round trip during my luch break, car was ok, parked the car...got back to work, 3 hrs later i enter the truck to drive home, as soon as i start the car and engage gear, i hear a high pitched warning sound and all the lights on my dash light up, brakes rare pretty useless, gotta stomp on them with all my might b4 the truck stops.....

i have had the buzzing/pulsing brake pedal issue for 2 yrs now, so i guess it has finally crapped out, dont have the $$$$$s for a new MC/brake system, so i intend to pick a used unit from ebay, and go from there...........need to figure out how to manually bleed the brakes after swapping out the bad unit [MENTION=66389]BlackWorksInc[/MENTION] i guess anyone with a similar pulsing brake issue, shoud prep for the day it craps out

Or if the motor unit starts buzzing pretty badly as that's probably an issue with the brushes as the motor starts wearing out.

But see in your vehicle unlike the OP's you had warning lamps and DTCs set before the vehicle even left the parking spot. So in your case the system functioned correctly in terms of warnings/failsafes and you were not driving the vehicle when it decided to just die all the sudden (not to mention this was a progressive failure vs. a random catastrophic failure.)

 

[meanmachine]

add me to the list. yesterday my dash abs and brake lights came on with the buzzing warning sound. brakes still felt fine as I assume the accumulater was still pressurized. drove to the shop where I work. looked under the hood and disconnected the electrical connectors around the master cylinder just hoping for a bad connection of some sort. which I was sure wasn't the problem. then as I got in the runner to drive back I had no assist, pedal went to the floor like I was trying to compress a brick just to stop. getting ready to go outside to check power master motor. also no codes came up before hand.

 

[4runnercolo]

FYI I got my replacement motor assembly from 1-800 9-parts-1. They have ads on ebay for these m/c complete units, but I could not stomach 1000 for a used unproven part that could fail right away.

I called them direct to find a better option and they were really helpful, and they sell just the motor assembly for $345. I don't think they advertise those on ebay.

I was still wary but the unit I got was super clean, looked brand new, and has been working perfect and quiet thus far. It was really pretty straightforward to do the whole job. Disconnecting the red line was a bit scary, and I was ready for the worst, but nothing happened, no pressure was released thank goodness. I did the 40 pedal pumps prior to the work which is supposed to release the pressure. Other than that it was a piece of cake. The only special tool was a u-joint and several various length extensions to get the master out. Afterwards I drove it to a shop (with squishy but working brakes) who did a complete bleed with the special scan tool for $110.

All said and done it cost less than $500. I nearly shit my pants first when the brakes went out, then second when I first learned people were paying $3500 to fix this same problem.
The 4runner will be up for sale asap, once I find a clean low mileage 3rd gen to buy. Good luck!

 

[earthrealm]

FYI I got my replacement motor assembly from 1-800 9-parts-1. They have ads on ebay for these m/c complete units, but I could not stomach 1000 for a used unproven part that could fail right away.

I called them direct to find a better option and they were really helpful, and they sell just the motor assembly for $345. I don't think they advertise those on ebay.

I was still wary but the unit I got was super clean, looked brand new, and has been working perfect and quiet thus far. It was really pretty straightforward to do the whole job. Disconnecting the red line was a bit scary, and I was ready for the worst, but nothing happened, no pressure was released thank goodness. I did the 40 pedal pumps prior to the work which is supposed to release the pressure. Other than that it was a piece of cake. The only special tool was a u-joint and several various length extensions to get the master out. Afterwards I drove it to a shop (with squishy but working brakes) who did a complete bleed with the special scan tool for $110.

All said and done it cost less than $500. I nearly shit my pants first when the brakes went out, then second when I first learned people were paying $3500 to fix this same problem.
The 4runner will be up for sale asap, once I find a clean low mileage 3rd gen to buy. Good luck!

Pls can you confirm if the motor assy. Is a brand new unit or used..$ 345. Seems a bit steep for just the motor assy, when a used unit is going for abt the same price...


Also. How often does the repaired unit buzz now?

 

[m85476585]

I kind of tested stopping without the brakes yesterday...

I did the first test on a snowy dirt road since I couldn't find an empty one. Leaving the shifter in D, I slowly applied the parking brake. I was on a steep downhill, so it slowed me down a bit, but I wasn't able to stop. As I pressed the parking brake more to try to stop, I spun out before I could react. This is basically a worst-case scenario- a snowy, slippery dirt road, steep downhill, transmission in D not L, and not using the regular brakes at all.

Shifting to L will quickly slow you down, as long as you can get the speed low enough for it to get into first gear. On a steep downhill (at least 10% grade) it wouldn't shift into first over about 25mph. On a flat road, it's about the same, shifting into 1 between 25-30mph. From 45mph I threw it in L, and it took a while to get down to 25, but then it slowed down quickly. Using the brakes would help, obviously.

I also tested the parking brake on a flat, dry road. It wasn't very effective for stopping quickly, and I was afraid to press it more than about halfway because I didn't want to lock the rear wheels. Even in 4H it's possible to lock just the rear wheels. You could lock the center differential, but you probably won't have time or won't think of it if the brakes go out. I stopped testing because I don't think the parking brake is designed for this sort of thing, and I don't want to damage it or wear it out.

It's unlikely that you will loose power brakes and have to quickly come to a stop at the same time. Most of the time when you are driving there is plenty of room to stop. You will most likely get a warning beep if the system malfunctions. And we've only heard of a small number of these systems failing so far.

 

[4runnercolo]

Yes that was the price for a used unit. New it lists at $1400, and the cheapest I could find new was over $1000. I think that is just for the electric motor, not for the assembly with the canister etc. For an 03 the complete m/c assembly, used, cost about $1,000 on ebay.

The ones for 05+ are cheaper b/c there are more of them to be found. If you have an 05+ you could replace the whole unit with a used one for about $400.

Maybe the motor/canister assembly for an 05+ is cheaper too.

I felt like 345 was a deal. And I did a LOT of research and calling around, I was not going to pay thousands for a m/c fix. On my 98 the m/c went out, it cost $80, and I was back on the road in a couple hours. That's progress for ya!

 

[4runnercolo]

The used unit I put on buzzed pretty loud at first, when the system was first charging up. You could hear it from the drivers seat. I thought, "great I got a bad one". But it soon quieted down and you cannot hear it run anymore, unless you have your head under the hood, then it sounds like a normal quiet electric motor. Judging by the appearance of the exterior of the unit, I would guess it has very low miles, it looks brand new. If I planned to keep this vehicle for a long time I probably would have cracked it open and inspected the brushes, just for piece of mind.

My old one was all crusty and had surface rust on the outer motor casing.

If you hear the high pitched solid buzzer, pull over now, you are about to lose your brakes ('s power assist). If this is your wife's/kid's vehicle make sure they know that!

 

[Greydog]

Sub'd, mine buzzes every 2-3 hits of the brake pedal (not hard either), used to be 4-5 about 6 months ago.

 

[earthrealm]

Sub'd, mine buzzes every 2-3 hits of the brake pedal (not hard either), used to be 4-5 about 6 months ago.

Nice, it appears ur system is getting better with age...
With the car off, ignition on, have you noticed the interval btw buzzing?

 

[jmauld]

That's what makes his particular case so odd to me. The units usually do set a DTC or even start sounding odd before they ever get that bad.

If you look at the majority of Master Cylinder failures you'll see there's usually a DTC for pressure, voltage, and/or some other failure. If there isn't a DTC there's a complaint of excessive noise (buzzing, ect.) or the brakes starting to feel weird (from the pump not being strong enough and/or the accumulator bleeding off pressure.) The OP's failure is very very odd in how quickly and completely it occurred.

Just another data point. Mine failed without any previous noise from the motor. I got the dash warning, but honestly with the buzzing and the illumination of so many lights, I was a bit confused as to what exactly the warning was for. Fortunately, I did back off and slow the truck down while I still had reserves, but the last 10 miles home was done with the flashers on and using manual braking. If you push hard enough on the pedal it will stop.

 

[dcx5000]

My complete story

Turned the 2003 4Runner Limited on one day at got the audible "alarm" letting me know the brakes won't work. Using this forum, I was able to diagnose the problem as a faulty ABS booster pump. I got by for a week, using a crowbar to tap on the pump motor when ever it would shut down, but then it went completely dead. My mechanic said he didn't want the job. The dealership quoted me $3200. I decided to order a used booster pump from 1888parts or whatever off ebay for around $400.
I removed the master cylinder from the car. I don't really like to work on cars. It was a little intimidating to tear apart the dash to reach the nuts on the back of the master cylinder. I removed this pesky ABS controller? bracket to reach the upper left nut. This was a mistake as that bracket is also difficult to remove. You can reach all the nuts using different socket extensions and maybe an elbow extension.
New (used) motor in and everything is back together. Motor doesn't work. I call 1888parts and they send me out a new "used" motor. I didn't have to send the first one back, so that was cool.
I recruited an old friend who is a certified mechanic to help me out. I bring him the master cylinder (not the entire car) and the new motor. He tests the new motor and it works, but is slightly a different size. He fabricates a custom bracket to mount the motor back on the master cylinder assembly. I reinstall the assembly.
My friend came over with his $400 scan tool. We turn the car on and the motor works. The scan tool is not a Toyota only tool. It is not that special, but gets the job done. I don't know if the scan tool would have worked if I had installed an entirely new master cylinder assembly.
We bleed the master cylinder first, and then the front brake lines. We started to bleed the back lines, but then aborted this because he said they appear to be fine.
Now everything works but the VSC light is on and we had to do the zero point calibration (see youtube). It works on the second try. The brakes now work exactly the way they were before.

 

[dkyleb]

I need to not read threads like this...

 

[Binjinh]

Multiple Brain Cells.

This

 

[Neil McCauley]

Sorry to resurrect a thread, but I guess add my 2005 Sport 4WD to the list of brake failures..

On way home yesterday, on came the red "!" brake light warning on the right dash, plus the other brake lights. A few minutes later, a continuous high pitched "EEEEEEEEEEE" alarm. Brakes found to have little to no pressure, basically leaving vehicle unstoppable without me absolutely stomping on the brake. I can get some pressure from the pedal if I pump it repeatedly but it has no effect on stopping power, and it then loses pressure in a few seconds anyway.

Temps have been -5*F to 10*F overnight here recently and I had (maybe stupidly) just taken it through a carwash the night before this...so it sat dripping wet in my driveway that night in <0*F temps, and maybe soapy water got somewhere it wasn't supposed to, froze, and ?? Seemed fine driving yesterday before this though. :noidea:

Taking it in today. Who knows, maybe it's just something minor like needs fluid changed or ice somewhere that needs to thaw. But from what I've found online from others with similar problems, it'll cost well over $1k. I just bought the vehicle from its single prior owner this summer and though it does have 150k miles it had seemed very clean and well maintained with great service records, newly replaced rotors, pads, fluids, etc. Thought I did plenty of research on it and this year/model in general before buying. But never heard anything about this. You'd think such a high-cost and high-risk safety item like this would be better known about.

 

[Kyler TM87]

2022 complete brake failure

After a long break. Here to write more about my 2003 4Runner Limited V8 4WD.

A few months ago my brakes went out. Had the full dash light up. Abs vsc trac control light up and the death tone constant beep. Thankfully it was night so no traffic. I was able to downshift and ease into the e brake to come to a stop. The pedal was rock solid. Took both feet pressure to make the brakes “work”. Fast foreword a few months. I replaced the full Master cylinder, Accumulator and the ABS motor. 3 separate parts purchased separately. Paid too much for shipping to Hawaii. Grand total with shipping was $2,156 for all 3 parts ordered and shipped separately. That being said I was quoted $3,700 from the local dealership so I’m my head I win. 1 tow to the shop 2 times on the lift and finally a 3rd disassembly in the driveway my brakes work again! Gravity bled the lines. And tightened up the E brake.

Have seen quite a few posts on the 4th Gen Facebook page about other peoples brake issues lately so figured I’d post my experience.

also those 4 bolts that hold the master to the firewall are a bi***. Especially that top left one

Still don’t really know how this forum works. My technical skills not there. Posting this here hoping someone sees it and appreciates it.

Next on my list finally gotta get around to installing the 1/4 strut spacer on the driver side to make the tire run not so bad.

Aloha! \m/