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

Has your 100 series LC experienced total -or near total- brake failure?

  • No.

    Votes: 944 78.0%
  • Yes. My truck had between 0 and 50k miles at the time.

    Votes: 1 0.1%
  • Yes. My truck had between 50k and 100K at the time.

    Votes: 11 0.9%
  • Yes. My truck had between 100K and 150k at the time.

    Votes: 52 4.3%
  • Yes. My truck had between 150k and 200k at the time.

    Votes: 84 6.9%
  • Yes. My truck had between 200k and 250K at the time.

    Votes: 70 5.8%
  • Yes. My truck had between 250k and 300k at the time.

    Votes: 36 3.0%
  • Yes, My truck had over 300k at the time.

    Votes: 18 1.5%

  • Total voters
    1,210
Joined
Oct 25, 2020
Messages
8
Location
Canada
200 series has the same problem. I guess before buying one, everyone needs to budget some time and $$ to have the accumulator motor redone.
 
Joined
Oct 25, 2020
Messages
8
Location
Canada
@hippoinacar I have not heard of many reports. Do you have additional info to share?
The evidence for this is on ebay --- similar parts for the 200 series are on sale on ebay for well over $1k. Since many of the problem is caused by motor wear, which will eventually happen, the 200 series will face same problem in due time.
 

hoser

SILVER Star
Joined
Dec 21, 2003
Messages
10,499
Location
Bay Area, CA
@hippoinacar I'm not really worried about eventual failure from wear and tear. All brake boosters eventually fail. I'm more worried about catastrophic failure... as in the brake pedal goes to the floor and pumping the brakes does not help any... like the title of the thread, "Total brake failure."

The availability of parts on eBay does not exactly equate to "total brake failure." I was sort of hoping you had more.
 

bentonrover

GOLD Star
Joined
Feb 19, 2012
Messages
989
The evidence for this is on ebay --- similar parts for the 200 series are on sale on ebay for well over $1k. Since many of the problem is caused by motor wear, which will eventually happen, the 200 series will face same problem in due time.

The techs I talked to at my local dealership and even the parts guy said they are different. Granted it is a wear item but they won't fail in the same fashion as the 100 series. They haven't seen one come in yet. Couple of 100's years back but nothing in recent memory. As to eBay I would say its just a part out of a vehicle.
 
Joined
Oct 25, 2020
Messages
8
Location
Canada
Got schooled by 2 folks above. But I am glad that we don't have to worry about that in the 200 series then. Been watching the market lately.
 

flintknapper

SILVER Star
Joined
May 22, 2004
Messages
9,488
Location
Deep East Texas
Had to go back in and change my vote. Mine failed at 235K.

Waiting on parts to arrive (new booster motor and accumulator), just finished rebuilding the Master Cylinder and cleaning up the reservoir. Have new reservoir grommets on order.

Will report back later the 'issues' once I have completed the repair.
 
Joined
Feb 24, 2017
Messages
85
Location
Maryland
Mine failed at 238k. Motor stopped coming on. I also tried pumping the brakes rapidly just to see what happened and my ABS light came on and it started beeping. Good thing I didn't drive this thing for our roadtrip last weekend.

Changed my vote as well. I thought about just buying a new motor and accumulator and rebuilding the master cylinder, but it's such an old part I don't want the same thing to happen a few years later.

Brand-new brake master assembly incoming.
 
Joined
Apr 30, 2020
Messages
342
Location
San Diego, CA
Mine failed at 238k. Motor stopped coming on. I also tried pumping the brakes rapidly just to see what happened and my ABS light came on and it started beeping. Good thing I didn't drive this thing for our roadtrip last weekend.

Changed my vote as well. I thought about just buying a new motor and accumulator and rebuilding the master cylinder, but it's such an old part I don't want the same thing to happen a few years later.

Brand-new brake master assembly incoming.
What year is your vehicle?
 
Joined
Nov 4, 2007
Messages
10,491
Location
Colorado
IMHO most of these brake failures are preventable, in the relative shorter term.

It's difficult to define short term. As brake usage in a perfectly health brake system, is so varied. As some are constantly on brake pedal ever few feet (stop and go traffic). Whereas others may go ~200 or more miles without touching pedal on regular basis (HWY vehicle). The 1 million mile Toyota had no brake issues reported IIRC.

It is sudden zero pressure in brake master and lines, that yields pedal to the floor (relatively no usable brakes). This happens from lose of fluid or brake booster pump motor failure.

Eventually all brake booster motor will fail. It's the motor failing to start that yields zero pedal more than anything else I've seen. As the motor turns the pump, pressurizing the accumulator.


A few tips:

First, never ignore brake warning lights or alarms.

Second, after vehicle has sat for a few hours (pressure bleeds down over time, the older the system the faster it bleeds down) or more. Turn IG key to ON, than wait and listen before starting engine. You'll hear brake booster motor run for up to 40 seconds. Not hearing or hearing run time longer is a warning. If not heard, press brake pedal a few times, it should than be heard. If motor does take all of 40 second run time before stopping, that should be investigated but is considered okay to drive.

Periodically test booster motor run time. Do this by pumping brake pedal 40 times with IG key off or key out of IG. Than turn IG key to ON, and time booster motor run time. 40 seconds is max. 28 second is a very health system with new master assy, good fluid and caliper pistons and seals. 40 seconds is limit, but may indicate some weakness. i.e low voltage/amp, weak seals, bad fluid, etc. Over 40 second and service is necessary.

Prevent measures.
  1. Flush brake fluid often. No longer time period between flushes than 3 years, after first factory fluid flushed out.
  2. I've gone back to using only Toyota brake fluid. It's pricey and may not make any difference, as Toyota no-longer states on bottle who makes. But the extra cost for piece of mind, for what is stated on the bottle "engineered to Toyota spec" may help protect internal seal. If seal weep/leak under pressure, motor will run excessively.
  3. Inspect motor run time and listen for excessive running of motor.
  4. Never overfill brake fluid reservoir. Fluid may escape from cap or grommets at bottom. If fluid get on booster motor brake control wires, it may enter boots protecting wires at connection points. The ensuing corrosion from hygroscopic action, will increase resistance of brake control wires. This will hasten motors failure, very rapidly. Brake fluid may also get into breather port for motor. The moisture will attack dust. This may clog breather and then as motor creates a vacuum (high RPM spin) it will suck fluid from pump into motor.
  5. Inspect breather at bottom of booster motor annually. Deep water crossings, driving in tall grasses, muck, very dusty condition, missing fender or undercarriage shielding, lifted increase open area in fender to engine bay, oversize tires, etc. May all add to debris entering engine compartment. Be on the watch and check breather more often under these or extreme driving condition. Or ensuing fluid sucked into motor will damage brake booster motor.
  6. Keep battery, battery post and clamps properly serviced. Volt/Amp drop from battery, will be the same as increased resistance in wires. This will effects RPM (slowing) and life of all motors. The brake booster motor and fuel pump motor of the most concern.
  7. Keep grounds to frame, body and engine properly serviced.
Hope this helps. Be safe!
 

Racer65

SILVER Star
Joined
Jan 28, 2012
Messages
2,999
Location
Palo Alto, CA
My company (City Racer LLC) has developed a new replacement pump motor (47960-60010) that addresses the shortcoming of the OEM unit. I'd like to invite 1 IH8MUD member to participate in trial testing. Basically, what this means is that you'll receive a new (not rebuilt) motor from us free of charge. In turn, you'll agree to install the unit promptly and provide feedback. Please PM me if you're interested.

47960-60010.jpg
 

flintknapper

SILVER Star
Joined
May 22, 2004
Messages
9,488
Location
Deep East Texas
My company (City Racer LLC) has developed a new replacement pump motor (47960-60010) that addresses the shortcoming of the OEM unit. I'd like to invite 1 IH8MUD member to participate in trial testing. Basically, what this means is that you'll receive a new (not rebuilt) motor from us free of charge. In turn, you'll agree to install the unit promptly and provide feedback. Please PM me if you're interested.

View attachment 2545029

Good Grief.....I literally just put a new one in my vehicle yesterday! NOW.....you post this.
 
Joined
Dec 17, 2019
Messages
227
Location
Centre, Alabama
My company (City Racer LLC) has developed a new replacement pump motor (47960-60010) that addresses the shortcoming of the OEM unit. I'd like to invite 1 IH8MUD member to participate in trial testing. Basically, what this means is that you'll receive a new (not rebuilt) motor from us free of charge. In turn, you'll agree to install the unit promptly and provide feedback. Please PM me if you're interested.

View attachment 2545029
Quite stoked to see how this turns out!
 

flintknapper

SILVER Star
Joined
May 22, 2004
Messages
9,488
Location
Deep East Texas
My company (City Racer LLC) has developed a new replacement pump motor (47960-60010) that addresses the shortcoming of the OEM unit. I'd like to invite 1 IH8MUD member to participate in trial testing. Basically, what this means is that you'll receive a new (not rebuilt) motor from us free of charge. In turn, you'll agree to install the unit promptly and provide feedback. Please PM me if you're interested.

View attachment 2545029

Are you at Liberty to say what 'improvements' have been made/incorporated into this version?
 

Racer65

SILVER Star
Joined
Jan 28, 2012
Messages
2,999
Location
Palo Alto, CA
Are you at Liberty to say what 'improvements' have been made/incorporated into this version?
There are 2 key areas, which I'll elaborate on after the part goes live. One is the heat dissipation hole on the OEM unit that allows water and oil to enter and contaminate the electricals. We moved the location of this hole to mitigate the issue. Second has to do with an area inside the alloy section of the pump where the factory machining process has tolerance control issues. That's why some OEM pumps last longer than others.
 
Joined
Nov 4, 2007
Messages
10,491
Location
Colorado
There are 2 key areas, which I'll elaborate on after the part goes live. One is the heat dissipation hole on the OEM unit that allows water and oil to enter and contaminate the electricals. We moved the location of this hole to mitigate the issue. Second has to do with an area inside the alloy section of the pump where the factory machining process has tolerance control issues. That's why some OEM pumps last longer than others.
"There are 2 key areas, which I'll elaborate on after the part goes live. One is the heat dissipation hole on the OEM unit that allows water and oil to enter and contaminate the electricals. We moved the location of this hole to mitigate the issue. Second has to do with an area inside the alloy section of the pump where the factory machining process has tolerance control issues. That's why some OEM pumps last longer than others"

Can you share some additional info: RPM of motor, Resistance of brake control wire, Pump flow rate and Pressure produced. Both for new OEM and your aftermarket as a comparison.
 

Max.Powerzz

Cruisers and Art!
Joined
Mar 24, 2006
Messages
916
Location
Denver
IMHO most of these brake failures are preventable, in the relative shorter term.

It's difficult to define short term. As brake usage in a perfectly health brake system, is so varied. As some are constantly on brake pedal ever few feet (stop and go traffic). Whereas others may go ~200 or more miles without touching pedal on regular basis (HWY vehicle). The 1 million mile Toyota had no brake issues reported IIRC.

It is sudden zero pressure in brake master and lines, that yields pedal to the floor (relatively no usable brakes). This happens from lose of fluid or brake booster pump motor failure.

Eventually all brake booster motor will fail. It's the motor failing to start that yields zero pedal more than anything else I've seen. As the motor turns the pump, pressurizing the accumulator.


A few tips:

First, never ignore brake warning lights or alarms.

Second, after vehicle has sat for a few hours (pressure bleeds down over time, the older the system the faster it bleeds down) or more. Turn IG key to ON, than wait and listen before starting engine. You'll hear brake booster motor run for up to 40 seconds. Not hearing or hearing run time longer is a warning. If not heard, press brake pedal a few times, it should than be heard. If motor does take all of 40 second run time before stopping, that should be investigated but is considered okay to drive.

Periodically test booster motor run time. Do this by pumping brake pedal 40 times with IG key off or key out of IG. Than turn IG key to ON, and time booster motor run time. 40 seconds is max. 28 second is a very health system with new master assy, good fluid and caliper pistons and seals. 40 seconds is limit, but may indicate some weakness. i.e low voltage/amp, weak seals, bad fluid, etc. Over 40 second and service is necessary.

Prevent measures.
  1. Flush brake fluid often. No longer time period between flushes than 3 years, after first factory fluid flushed out.
  2. I've gone back to using only Toyota brake fluid. It's pricey and may not make any difference, as Toyota no-longer states on bottle who makes. But the extra cost for piece of mind, for what is stated on the bottle "engineered to Toyota spec" may help protect internal seal. If seal weep/leak under pressure, motor will run excessively.
  3. Inspect motor run time and listen for excessive running of motor.
  4. Never overfill brake fluid reservoir. Fluid may escape from cap or grommets at bottom. If fluid get on booster motor brake control wires, it may enter boots protecting wires at connection points. The ensuing corrosion from hygroscopic action, will increase resistance of brake control wires. This will hasten motors failure, very rapidly. Brake fluid may also get into breather port for motor. The moisture will attack dust. This may clog breather and then as motor creates a vacuum (high RPM spin) it will suck fluid from pump into motor.
  5. Inspect breather at bottom of booster motor annually. Deep water crossings, driving in tall grasses, muck, very dusty condition, missing fender or undercarriage shielding, lifted increase open area in fender to engine bay, oversize tires, etc. May all add to debris entering engine compartment. Be on the watch and check breather more often under these or extreme driving condition. Or ensuing fluid sucked into motor will damage brake booster motor.
  6. Keep battery, battery post and clamps properly serviced. Volt/Amp drop from battery, will be the same as increased resistance in wires. This will effects RPM (slowing) and life of all motors. The brake booster motor and fuel pump motor of the most concern.
  7. Keep grounds to frame, body and engine properly serviced.
Hope this helps. Be safe!

Admins, if it's not already, it would be great to put this in the FAQ sticky. This thread has grown so large it was difficult for me to track down the different steps to test out the booster. 2001LC has laid them all out here very nicely and clearly. I had the chance to hang out with him for an afternoon last weekend, he has to be one of the most knowledgeable (and coolest) people on the continent about these brake boosters and 100s in general. Thanks Paul!
 

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