Poll on total brake failure in 100 series (2 Viewers)

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

  • No.

    Votes: 1,189 74.2%
  • 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: 13 0.8%
  • Yes. My truck had between 100K and 150k at the time.

    Votes: 69 4.3%
  • Yes. My truck had between 150k and 200k at the time.

    Votes: 127 7.9%
  • Yes. My truck had between 200k and 250K at the time.

    Votes: 117 7.3%
  • Yes. My truck had between 250k and 300k at the time.

    Votes: 67 4.2%
  • Yes, My truck had over 300k at the time.

    Votes: 32 2.0%

  • Total voters
    1,602

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Yes, ‘03 LX470, 253k KMs (157k miles) back in 2016.
Was the brake booster failure. Loud alarm, total brake failure, wife was driving alone when it happened and pulled over safely with both feet on brake pedal on a side street.

Toyota quoted $4700 (insane!) for the MC replacement as they wouldn’t sell just the booster.
Found a rebuilt booster on eBay for around $500 and a mechanic was able to install it without removing the MC (from watching YouTube videos for bolt locations). All in cost me around $700 CAD.
 
Successfully rebuilt my buddy's MC, ran into a snag, his rear bleeder screws are rusted to shiets and is in really bad shape, i'm not certain next time around they'll come out in 1 piece. Does anyone have the part number for the OEM ones, or what size they are so i can get him a new pair?
 
Successfully rebuilt my buddy's MC, ran into a snag, his rear bleeder screws are rusted to shiets and is in really bad shape, i'm not certain next time around they'll come out in 1 piece. Does anyone have the part number for the OEM ones, or what size they are so i can get him a new pair?

The rear calipers?
47547-60020

is the OEM part
 
Successfully rebuilt my buddy's MC, ran into a snag, his rear bleeder screws are rusted to shiets and is in really bad shape, i'm not certain next time around they'll come out in 1 piece. Does anyone have the part number for the OEM ones, or what size they are so i can get him a new pair?
Rear bleeders are the most likely damaged by not keeping good bleeder caps on. I go the extra step when bleeding, to blow out the bleeders. Reason; brake fluid remains in them. Brake fluid attracts moisture. If rusts gets too bad, it can damage caliper. Then a new caliper is required, just because a $2 rubber cap is missing.

I replace bleeder caps on near every rig I work on or look at. Why ASE shop/Dealership don't replace or leave off, well...... they'll differently get more and costly work out of a brake job if they don't!

In most case we can just install new rear bleeder 47547-12030 .
Fronts are longer to aid in getting a wrench on 47547-60020
 
Successfully rebuilt my buddy's MC, ran into a snag, his rear bleeder screws are rusted to shiets and is in really bad shape, i'm not certain next time around they'll come out in 1 piece. Does anyone have the part number for the OEM ones, or what size they are so i can get him a new pair?
Did you test for leaks by first timing booster run time test (30 to 40 sec) and then/also inspecting for leaks after de-greasing! It's very important!
 
Could use some input @2001LC or others with knowledge of these systems. One day I noticed my pump was kicking on pretty frequently in traffic (every 3-4 pedal pushes). I had never really noticed it before. The motor sounds pretty normal although I don't remember it being quite loud enough to hear in the cab before. My pedal is also a bit softer than it was before. Not sure if this is the Bosch rotors/pads wearing or the MC losing pressure.

Anyhow, I got about 40 seconds using the FSM depressurize then turn the key on method. I then decided I'd rebuild the MC since it was cheap and may be preventative.

I used techstream to bleed all 4 corners then took it for a drive. Now it seems the motor runs nearly every time I push the brakes and the pedal feels similarly soft as before.

I'm hoping I just need to keep bleeding, but it still doesn't describe the soft pedal.

Anyone have any ideas/experienced something similar?
 
I often get over 40 sec. with booster run time test, after flushing brakes. Book states re-bleed if this happens. But I always find I've a leak at bleeder or two or three. Bleeder needs to be de-grease inside and out. Then use brakes hard and actively numerous times. Then inspect for seepage at bleeder. I'll then sung down leaky bleeder ~1ft-lbf at a time above the 7ft-lbf starting point, until I hit about 12ft-lbf. If doesn't stop by then, I'll replace bleeder with new OEM. Remember to always keep good bleeder rubber caps on.

Also you must do same for any fitting, like flare nut(s) of lines you removed. Check all lines while at it.
 
I often get over 40 sec. with booster run time test, after flushing brakes. Book states re-bleed if this happens. But I always find I've a leak at bleeder or two or three. Bleeder needs to be de-grease inside and out. Then use brakes hard and actively numerous times. Then inspect for seepage at bleeder. I'll then sung down leaky bleeder ~1ft-lbf at a time above the 7ft-lbf starting point, until I hit about 12ft-lbf. If doesn't stop by then, I'll replace bleeder with new OEM. Remember to always keep good bleeder rubber caps on.

Also you must do same for any fitting, like flare nut(s) of lines you removed. Check all lines while at it.

I'll try bleeding again. I suspect the accumulator didn't get bled entirely.

How often does your pump kick on when driving? Does 3-4 brake pushes sound excessive? It only kicks on for a few seconds each time.
 
I'll try bleeding again. I suspect the accumulator didn't get bled entirely.

How often does your pump kick on when driving? Does 3-4 brake pushes sound excessive? It only kicks on for a few seconds each time.
The accumulator is bleed by depressing peddle 40 time key off. The FSM recommends pre -bleeding master when it's replaced or rebuilt. But not big deal. Just flushing the system bleeding all 4 generlly takes care of all that. Just keep fluid level above min as you work. brake peddle should feel firm and normal once you've air out. Remember, for first bleed of a front caliper, pump peddle 20 times, then about 5 pump thereafter. Front take about 7 to 10 bleeds each bleeder.

The booster may come on just from one push on peddle, 3 or 4 is fine. Most just never notice booster runs often.
 
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Well that was short lived, i rebuilt my friend's MC with the new piston kit. It worked fine for a few days, couple days ago as he was driving, he said the pump didn't stop running, and he can hear what seems like air escaping from inside the cabin. I've pre-bled the MC, i bled all 4 corners regularly, then i used a matco scanner to bleed the ABS system. At this point i think something else is up, accumulator not holding pressure?
 
If not bubbling up in reservoir any longer. Than I'd say cylinder kit worked. This may be secondary issue. Could be accumulator! If so it may be best to buy the booster assembly (motor, pump, accumulator and control wire)
I'd check end to end for leaks, first thing.
 
It's still bubbling up in the reservoir last time i checked, however the screeching crow noise isn't there anymore, it's just really loud air sound. I am certain i bled the entire system as well as the ABS, unless i gotta bleed it again? I bled the ABS using scan tool, only once, each corner. Problem still persists. There's full braking power however, just the warning sound and pump won't stop pumping.
 
Did you time how long booster motor runs. spec 30 -40 seconds. Every time I flush/bleed, if times runs over, I've a leak at bleeder(s)
2030117
 
Hey Guys, I was driving my dads 100 today and noticed the pedal soften and sink while at a stop light. I have read through all the threads that I can find and plan on doing a master cylinder rebuild and sending my booster motor to Eurton to be rebuilt. I have seen some reference to replacing the accumulator right away and was wondering if thats a good choice or an unnecessary expense?

Truck is a 2003 with 281,XXX on the clock.

And yes I participated in the poll.

Thanks, Joe
 
Have a 2004 with ~152k miles. In the last several months, on multiple occasions got the ABS & VSC warning lights and buzzing alarm, it went away but often heard a sound from the master cylinder area that sounded like an electric motor screeching/dying. Read this thread and other great info on ih8mud, and had the booster/accumulator 47070-60010 replaced. Now no problems at all. See the photos of the old part--major, very serious corrosion at the electrical connections, and the electric motor was very loose and sloppy inside, with major metal residue from grinding. Very glad got it done before it was too late; the shop mechanics were shocked at the corrosion and metal dust inside.

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Have a 2004 with ~152k miles. In the last several months, on multiple occasions got the ABS & VSC warning lights and buzzing alarm, it went away but often heard a sound from the master cylinder area that sounded like an electric motor screeching/dying. Read this thread and other great info on ih8mud, and had the booster/accumulator 47070-60010 replaced. Now no problems at all. See the photos of the old part--major, very serious corrosion at the electrical connections, and the electric motor was very loose and sloppy inside, with major metal residue from grinding. Very glad got it done before it was too late; the shop mechanics were shocked at the corrosion and metal dust inside.

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Very good info, thanks for sharing.

Any change you can post more pictures of commutator?
I can see it's worn, but need clearer pictures, and to see all 360 degrees of copper plates of commutator.

Commutator, is the copper part that brushes ride on.
2031528
 
Oh well!
I do see your commutator worn deep. I don't see that on normal good ones with good control wire.

I most often see some dark spots. This is were copper is gone and insulator is exposed.

Do you happen to recall seeing that/this?
Insulator under commutator seen in three spots, as copper was worn all the way down in those three spots
2032177
 
Just put in the new unit for my buddy, bled all the brakes per FSM, used scan tool to bleed ABS, went on dirt road to activate ABS. Everything seems to be working and no more air hissing or alarm. Now there's a slight problem, not sure if it's a problem but the brake pedal is really really sensitive, and firm, and high up. If i just nudge it the truck will start slowing down. It's like there's no play at all before it bites, it's instagrab. Is there a way to adjust the pedal some how so at least there's a little play before it starts to activate?
 

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