Poll on total brake failure in 100 series (1 Viewer)

[Jack90210]

Just did this for the first time on my original booster. Definitely some corrosion but looks (mostly) isolated to the screws. Any cause for concern here? I've been considering grabbing a booster during the current sale to keep on the shelf. Not noticing any screeching noises or braking issues - and I get a 36-37 second booster motor runtime running the standard test.

View attachment 3881281

If it were me I'd clean off the corrosion and replace the screws.

 

[rexington14]

If it were me I'd clean off the corrosion and replace the screws.

Thanks for the input. I decided to just run it. Maybe will spray it with something safe (tbd) and hit it with a brush.

My poor LC didn't get anything during this sale. The Corolla however is getting a new air filter, thermostat, water inlet, radiator, and hoses

 

[100s]

I voted no, one with 259,000 and one with 276,000

 

[FrigginFGO]

Brake booster and accumulator replaced last month on my 2004 with 93,000 miles. I kept hearing grinding shortly after start up from somewhere behind the dash. A few weeks later my ABS light came on which led me to get the issue diagnosed. The sucky thing was brake booster was on backorder for a week because I wanted an OEM replacement.

 

[rommeeeezy]

I just purchased a 1999 LC with 322k Miles on it. It was in pretty good shape, just had brake rotors and pads replaced, and the actual assembly looks to be in good. I dug through the thread a bit and was wondering if people are preemptively replacing these now? I don't have much history beyond the last 4 years and those were mostly suspension related fixes from the previous owner. And the owner before that was the first owner from 1999 - 2021 and there's no service records.

So are people mostly waiting to replace their full assembly or are they preemptively replacing them now with the prices lower? It seems like you could probably purchase a new one and pay for labor on the install for roughly the same cost as a full assembly just a few years ago.

 

[2001LC]

I just purchased a 1999 LC with 322k Miles on it. It was in pretty good shape, just had brake rotors and pads replaced, and the actual assembly looks to be in good. I dug through the thread a bit and was wondering if people are preemptively replacing these now? I don't have much history beyond the last 4 years and those were mostly suspension related fixes from the previous owner. And the owner before that was the first owner from 1999 - 2021 and there's no service records.

So are people mostly waiting to replace their full assembly or are they preemptively replacing them now with the prices lower? It seems like you could probably purchase a new one and pay for labor on the install for roughly the same cost as a full assembly just a few years ago.

Depends on clues.
bad staining in reservoir and corrosion on brake control wire, are two of the clues.

Brakes ...... Overdue write-up.

First and foremost: Brakes should only be worked by those, with high level of mechanical abilities and experienced with brake systems. With the age of all 100 series today, in our aging fleet. Any issue, with brake master assembly. IMHO, best and safest course of action. Have the whole brake...

forum.ih8mud.com

 

[Tychoice]

Depends on clues.
bad staining in reservoir and corrosion on brake control wire, are two of the clues.

Brakes ...... Overdue write-up.

First and foremost: Brakes should only be worked by those, with high level of mechanical abilities and experienced with brake systems. With the age of all 100 series today, in our aging fleet. Any issue, with brake master assembly. IMHO, best and safest course of action. Have the whole brake...

forum.ih8mud.com

Hi ! I spend the whole last night read up this thread since the beginning till now and 1st off I just wanted to say I really appreciated your time and effort on trouble shooting this well know issue on our vehicle since there is not much information on the ABS system on these rigs, so I have a 1998 with 270k miles on it I purchased 2 years ago, the original ABS pump on it was running very loud but at the time it was working and I thought it supposed to run like that, fast forward to last winter the dreadful ABS light and brake alarm is on but brake still work at that time, I swapped it out with a used unit on eBay and bleeded the system and everything was great, the original unit was in very bad shape like completely dusted and rusted out on the outside let alone internal, the new unit that I put in look very decent shape with unknown miles but it run very quite compared to the old one, I almost can't hear it running if I was in the rig, fast forward 2 months after it happened again and this time I COMPLETELY LOST BRAKE WITH OUT EBRAKE, luckily I made it home safe and parked the rig, let it sit for 2 days come out to start it lights went away and I can hear relays clicking and the pump is running fine, test drove around the blocks a few times nothing, than I drove a little farther and at a random parking lot it HAPPENED AGAIN brake pedal sink to the floor and completely no brake pressure, I parked the truck turned it off and turn it back on and it went away very strange, shut it off again turn it back on and the alarm went on and no pedal, which almost made me believe there is a short in the system cause no power to the pump but I'm not expert, I did a quick test around with my vol multimeter for fuses and relays and they seem to be working fine, I almost think it was the ABS module under the dash on driver side was bad or lose a ground or sth, but after founding this thread and spend the last night gathering information I got a few things down

- look like I overfilled the system, when the pump shut off completely and brake fluid return to reservoir, it's above max
- look like there is no thread about the ABS module is the cause for this, 9/10 is the whole pump itself
- I will try to get to my truck today and correct the fluid level, check for the brake wires control condition (I didn't check it when I swapped it in) and try to move the rig home for further diagnostics

I still have my original unit that I took out from the rig laying at my other house's garage, if this unit I just swapped in 2 months ago is indeed bad too, would you be interesting on 2 cores for more documents on the issue and I would definitely thinking about getting a rebuild unit from you directly, I don't want to go with eBay route or possibly salvage yard, want something reliable and well rebuild by experience tech

 

[2001LC]

You're try to diagnose and repair something you don't likely understand. Even techs at Toyota, don't. They just replace the whole master. For good reason.

My write up on brakes (master). Is to help all understand, how to care from them. Also, what clues to look for, that tells us, we may be heading for issues. I do not advocate repairing, brake master or the ABS unit.

I may recommend service the booster assemble. Which depends clues as to heath of masters. But replacing the master, is less labor than R&R of any part of it. With exception of the accumulator and reservoir.

Hi ! I spend the whole last night read up this thread since the beginning till now and 1st off I just wanted to say I really appreciated your time and effort on trouble shooting this well know issue on our vehicle since there is not much information on the ABS system on these rigs, so I have a 1998 with 270k miles on it I purchased 2 years ago, the original ABS pump on it was running very loud but at the time it was working and I thought it supposed to run like that, fast forward to last winter the dreadful ABS light and brake alarm is on but brake still work at that time, I swapped it out with a used unit on eBay and bleeded the system and everything was great, the original unit was in very bad shape like completely dusted and rusted out on the outside let alone internal, the new unit that I put in look very decent shape with unknown miles but it run very quite compared to the old one, I almost can't hear it running if I was in the rig, fast forward 2 months after it happened again and this time I COMPLETELY LOST BRAKE WITH OUT EBRAKE, luckily I made it home safe and parked the rig, let it sit for 2 days come out to start it lights went away and I can hear relays clicking and the pump is running fine, test drove around the blocks a few times nothing, than I drove a little farther and at a random parking lot it HAPPENED AGAIN brake pedal sink to the floor and completely no brake pressure, I parked the truck turned it off and turn it back on and it went away very strange, shut it off again turn it back on and the alarm went on and no pedal, which almost made me believe there is a short in the system cause no power to the pump but I'm not expert, I did a quick test around with my vol multimeter for fuses and relays and they seem to be working fine, I almost think it was the ABS module under the dash on driver side was bad or lose a ground or sth, but after founding this thread and spend the last night gathering information I got a few things down

Bottom line. Get a new brake booster assy with master (the whole brake master).

- look like I overfilled the system, when the pump shut off completely and brake fluid return to reservoir, it's above max

Overfilling, will not affect brake master operation, in the short term. But, it mayl in the long run.

- look like there is no thread about the ABS module is the cause for this, 9/10 is the whole pump itself
- I will try to get to my truck today and correct the fluid level, check for the brake wires control condition (I didn't check it when I swapped it in) and try to move the rig home for further diagnostics

I still have my original unit that I took out from the rig laying at my other house's garage, if this unit I just swapped in 2 months ago is indeed bad too, would you be interesting on 2 cores for more documents on the issue and I would definitely thinking about getting a rebuild unit from you directly,

No thanks you.
I'm done with my research (data point collection) on brake master booster motors.
At this time, I do not rebuild booster motors.

I would never buy or recommend, rebuilt brake master.

I don't want to go with eBay route or possibly salvage yard, want something reliable and well rebuild by experience tech

Booster motor, can be rebuilt. But so often, old brake master or its other components will fail shortly after a new or rebuilt booster motor installed.

Brakes are, the most important safety device. Your life and the lives others depend on them.

View attachment 3903148

Nice picture possier picture, of your 100 series. But pictures of brake master reservoir and control wires, would have been more helpful here today.

Bottom line. Get a new brake booster assy with master (the whole brake master).

Brake booster motor:
I've seen, more than once. Where the brake booster motors' commutator, has worn thin and has dead spots. The motor runs fine, when running. But sometimes, when it's time for motor to start running (fire-up). A brush happens to land on a deads spot, so booster motor will not fire up (run).

Overfilling the brake fluid reservoir a little, is not going to directly affect motor or operation or the ABS unit. Not in the short term. But, it will affect the booster motor and may affect ABS unit, in the long run.

The issue with overfill. Is when brake fluid comes out the cap/top. May even force brake fluid out the grommets in bottom of reservoir. The fluid may then travel down to brake control wire (resistance wires). Brake fluid once on wires. Then travels along wiresir, into its boot covering the contacts (contacts, leads, washers and screws). Brake fluid attracts moisture (hygroscopic) from the atmosphere. The moisture, being held in boot, results in corrosion of contacts.

The corrosion, on brake control (specific resistance) contacts. Increase resistance of wires. This result, in excessive heat between commutator and brushes. Which heat cause excessive wear of commutator. Premature failure of motor.

Seals within master:
When pressure drops within brake master. Brake booster motor gets signal to run. It turns the pump, forcing brake fluid into accumulator. If the non replaceable seals within master, are weak. They'll not hold full pressure. The loss of pressure, results in brake booster motor running. This may result in booster motor running excessively long. The booster motor is designed to run often, for short burst. If it runs continuously or prolonged periods. It creates excessive heat. This also will cause premature failure of motor (wear of brushes & commutator). These seals, are weakest when cold.

The ABS unit (black box) on master. Can also fail. The ones I've seen fail, have had very stained reservoir's and often corrosion on brake control wire.

 

[Tychoice]

You're try to diagnose and repair something you don't likely understand. Even techs at Toyota, don't. They just replace the whole master. For good reason.

My write up on brakes (master). Is to help all understand, how to care from them. Also, what clues to look for, that tells us, we may be heading for issues. I do not advocate repairing, brake master or the ABS unit.

I may recommend service the booster assemble. Which depends clues as to heath of masters. But replacing the master, is less labor than R&R of any part of it. With exception of the accumulator and reservoir.


Bottom line. Get a new brake booster assy with master (the whole brake master).

Overfilling, will not affect brake master operation, in the short term. But, it mayl in the long run.

No thanks you.
I'm done with my research (data point collection) on brake master booster motors.
At this time, I do not rebuild booster motors.

I would never buy or recommend, rebuilt brake master.


Booster motor, can be rebuilt. But so often, old brake master or its other components will fail shortly after a new or rebuilt booster motor installed.

Brakes are, the most important safety device. Your life and the lives others depend on them.

Nice picture possier picture, of your 100 series. But pictures of brake master reservoir and control wires, would have been more helpful here today.

Bottom line. Get a new brake booster assy with master (the whole brake master).

Brake booster motor:
I've seen, more than once. Where the brake booster motors' commutator, has worn thin and has dead spots. The motor runs fine, when running. But sometimes, when it's time for motor to start running (fire-up). A brush happens to land on a deads spot, so booster motor will not fire up (run).

Overfilling the brake fluid reservoir a little, is not going to directly affect motor or operation or the ABS unit. Not in the short term. But, it will affect the booster motor and may affect ABS unit, in the long run.

The issue with overfill. Is when brake fluid comes out the cap/top. May even force brake fluid out the grommets in bottom of reservoir. The fluid may then travel down to brake control wire (resistance wires). Brake fluid once on wires. Then travels along wiresir, into its boot covering the contacts (contacts, leads, washers and screws). Brake fluid attracts moisture (hygroscopic) from the atmosphere. The moisture, being held in boot, results in corrosion of contacts.

The corrosion, on brake control (specific resistance) contacts. Increase resistance of wires. This result, in excessive heat between commutator and brushes. Which heat cause excessive wear of commutator. Premature failure of motor.

Seals within master:
When pressure drops within brake master. Brake booster motor gets signal to run. It turns the pump, forcing brake fluid into accumulator. If the non replaceable seals within master, are weak. They'll not hold full pressure. The loss of pressure, results in brake booster motor running. This may result in booster motor running excessively long. The booster motor is designed to run often, for short burst. If it runs continuously or prolonged periods. It creates excessive heat. This also will cause premature failure of motor (wear of brushes & commutator). These seals, are weakest when cold.

The ABS unit (black box) on master. Can also fail. The ones I've seen fail, have had very stained reservoir's and often corrosion on brake control wire.

Appreciated for the write up ! I just moved my rig home and captured some photos on the pump for a better look at it, I did a few more test on the rig and here is what I got :
- I used a multimeter to check for power at the brake control wires and got 14v there
- I had my dad in the rig and turned ig on but not start the rig, I'm outside had my fingers on 3 relays in the fuse box, they all clicked one by one, pink 1st, blue 2nd, and green 3rd, they all clicked
- I then heard a very very small like humming noise almost like the abs pump want to turn on but couldn't
- Base on your write up above and as photos I uploaded, look like my brake wires and ABS black box bolts underneath are good, we had power at the pump itself at 14v, all relays clicked, very possibly that like you said the pump commutator had something to do with my rig situation, probably something inside broke and cause the pump not turning indicate by a small humming noise I heard in the engine bay
Look like my fix will be a whole new brake booster assembly aka the whole damn thing

 

[Tychoice]

Appreciated for the write up ! I just moved my rig home and captured some photos on the pump for a better look at it, I did a few more test on the rig and here is what I got :
- I used a multimeter to check for power at the brake control wires and got 14v there
- I had my dad in the rig and turned ig on but not start the rig, I'm outside had my fingers on 3 relays in the fuse box, they all clicked one by one, pink 1st, blue 2nd, and green 3rd, they all clicked
- I then heard a very very small like humming noise almost like the abs pump want to turn on but couldn't
- Base on your write up above and as photos I uploaded, look like my brake wires and ABS black box bolts underneath are good, we had power at the pump itself at 14v, all relays clicked, very possibly that like you said the pump commutator had something to do with my rig situation, probably something inside broke and cause the pump not turning indicate by a small humming noise I heard in the engine bay
Look like my fix will be a whole new brake booster assembly aka the whole damn thing

View attachment 3903972

View attachment 3903975

View attachment 3903976

 

[Tychoice]

This look like the problem too I think

 

[2001LC]

Appreciated for the write up ! I just moved my rig home and captured some photos on the pump for a better look at it, I did a few more test on the rig and here is what I got :
- I used a multimeter to check for power at the brake control wires and got 14v there
- I had my dad in the rig and turned ig on but not start the rig, I'm outside had my fingers on 3 relays in the fuse box, they all clicked one by one, pink 1st, blue 2nd, and green 3rd, they all clicked
- I then heard a very very small like humming noise almost like the abs pump want to turn on but couldn't
- Base on your write up above and as photos I uploaded, look like my brake wires and ABS black box bolts underneath are good, we had power at the pump itself at 14v, all relays clicked, very possibly that like you said the pump commutator had something to do with my rig situation, probably something inside broke and cause the pump not turning indicate by a small humming noise I heard in the engine bay
Look like my fix will be a whole new brake booster assembly aka the whole damn thing

View attachment 3903972

View attachment 3903975

View attachment 3903976

This look like the problem too I think

View attachment 3903999

If getting 14V to motor, and it just hums. Very likely issue with commutator and or brushes. Sometimes tapping on motor and repeatedly IG ON & OFF, it may fires up.

So you have 14 Volts at battery, also?
I assume the first picture (post #1229) of clean wires and screws. Is wire on motor side?
I assume the second picture (post #1231) of rusty wires and screws. Is wire on ABS side?
My understanding was, you had a used booster motor. But now I see you have a used: "whole damn thing"?

Installing used masters or rebuilt master. Is just plain risky. It also will 8 out of 10 times. Result in more labor and higher cost, in the long run. Which you now know why.

Bit the built, and be done with it.

 

[Tychoice]

If getting 14V to motor, and it just hums. Very likely issue with commutator and or brushes. Sometimes tapping on motor and repeatedly IG ON & OFF, it may fires up.

So you have 14 Volts at battery, also?
I assume the first picture (post #1229) of clean wires and screws. Is wire on motor side?
I assume the second picture (post #1231) of rusty wires and screws. Is wire on ABS side?
My understanding was, you had a used booster motor. But now I see you have a used: "whole damn thing"?

Installing used masters or rebuilt master. Is just plain risky. It also will 8 out of 10 times. Result in more labor and higher cost, in the long run. Which you now know why.

Bit the built, and be done with it.

That where I'm at the moment tbh, the last used unit I swapped in cost me $500 on eBay and that is all that I can afford at the moment to get the rig going again tbh, right now I'm in the middle of debating if I want to keep it or just swap another used unit in and sell it, or bits the bullet and spend $2500 on a brand new unit which double.my mortgage is crazy, my mortgage is like $1150 out here in Oklahoma

- Yes the 1229 picture is the control wires on the motor side
- 1231 picture with rusty bolts is for the ABS side
- Yes I have 14v at battery and 14v at brake control wire, all relays clicked so I'm leaning forward the motor had something broke in it cause that small hum noise almost sound like a fuel pump running when you crawl underneath the car before start the engine you can hear the fuel pump running, same noise but in the engine bay

Do you know where to get a good brake booster assembly beside spend $2500 , considering I paid just shy $3500 for my rig 2 years ago this is basically half of the rig

 

[2001LC]

That where I'm at the moment tbh, the last used unit I swapped in cost me $500 on eBay and that is all that I can afford at the moment to get the rig going again tbh, right now I'm in the middle of debating if I want to keep it or just swap another used unit in and sell it, or bits the bullet and spend $2500 on a brand new unit which double.my mortgage is crazy, my mortgage is like $1150 out here in Oklahoma

- Yes the 1229 picture is the control wires on the motor side
- 1231 picture with rusty bolts is for the ABS side
- Yes I have 14v at battery and 14v at brake control wire, all relays clicked so I'm leaning forward the motor had something broke in it cause that small hum noise almost sound like a fuel pump running when you crawl underneath the car before start the engine you can hear the fuel pump running, same noise but in the engine bay

Do you know where to get a good brake booster assembly beside spend $2500 , considering I paid just shy $3500 for my rig 2 years ago this is basically half of the rig

First I do not recommend you work on your brakes. Only qualified mechanics at Toyota should.

If on a beer budget. You could.

• Replace motor with new OEM.
• Rebuild motor.
• Have motor rebuilt.

New OEM comes with pump and accumulate, if you like.

I should work. But what you may find, is other issue, in other parts of master. The one I see the most, is weak seal. You'll still have brakes when these seal are weak. But as I stated earlier. Weak Seal (failure), may result in excessive long booster motor run times. Then you're back to square one, as this burns up the motors commutator.

What you paid for your rig. Has no bearing on safe and reliable vehicle. Either it is worth putting money into, for the long haul. Or its a junker to part out or dump..

When we piecemeal in junk, aftermarket and sub par service, we get junk. It catches up to us, and then all money and time is wasted

Search mud for the 25% sale I posted. You can get the whole damn thing, for under $1,500 to your door. If you catch the 25% off whole sale.

Use your VIN # when ordering.

Check part number at www.partsouq.com

 

[leveeguy]

Link below to very possibly the exact new part you need to replace for $1400. This part is for vehicles with VSC

Brake Master Cylinder Assembly with Fluid #47050-60042 | Autoparts.toyota.com

Ensure optimal braking with the Brake Master Cylinder Assembly with Fluid. Shop Genuine Toyota parts now!

autoparts.toyotaofdecatur.com

****Note: be sure to confirm correct part # for your exact vehicle and as previously mentioned provide VIN number if purchasing to be sure you receive correct part for your specific vehicle. If this part is not correct the price should be similar for the correct part you need.

 

[Tychoice]

First I do not recommend you work on your brakes. Only qualified mechanics at Toyota should.

If on a beer budget. You could.

• Replace motor with new OEM.
• Rebuild motor.
• Have motor rebuilt.

New OEM comes with pump and accumulate, if you like.

I should work. But what you may find, is other issue, in other parts of master. The one I see the most, is weak seal. You'll still have brakes when these seal are weak. But as I stated earlier. Weak Seal (failure), may result in excessive long booster motor run times. Then you're back to square one, as this burns up the motors commutator.

What you paid for your rig. Has no bearing on safe and reliable vehicle. Either it is worth putting money into, for the long haul. Or its a junker to part out or dump..

When we piecemeal in junk, aftermarket and sub par service, we get junk. It catches up to us, and then all money and time is wasted

Search mud for the 25% sale I posted. You can get the whole damn thing, for under $1,500 to your door. If you catch the 25% off whole sale.

Use your VIN # when ordering.

Check part number at www.partsouq.com

Thank boss ! I think that the route Im gonna go $1500 is in reasonable range buy one cry one, $2500 where I look is pretty touchy
- I was an apprentice for 1 years and half at my old local Napa Garage so I'm pretty confident on the job, last time I swapped it was pretty straight forward
- For the price I paid for my rig, paying someone else to touch it was never even an option when I 1st bought it
Appreciated for the head up link on the brand new booster and the write up !

 

[Tychoice]

Link below to very possibly the exact new part you need to replace for $1400. This part is for vehicles with VSC

Brake Master Cylinder Assembly with Fluid #47050-60042 | Autoparts.toyota.com

Ensure optimal braking with the Brake Master Cylinder Assembly with Fluid. Shop Genuine Toyota parts now!

autoparts.toyotaofdecatur.com

****Note: be sure to confirm correct part # for your exact vehicle and as previously mentioned provide VIN number if purchasing to be sure you receive correct part for your specific vehicle. If this part is not correct the price should be similar for the correct part you need.

Thank you friend for the 2nd head up ! Very appreciated !