If current not passing through ABS unit, to leads at bottom the wire (brake control wire to motor, in soft rubber boot) connected to. Than likely the ABS unit has failed. I've seen it happen twice!
Poll on total brake failure in 100 series
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I believe thanks to @2001LC I have found the reason why the old pump motor failed, is this a commutator past its serviceable life?
Now the question is "Why is the new motor not working???" I see current at the terminals, I guess I am pulling the MC back out to bench test the motor and inspect it?
Now the question is "Why is the new motor not working???" I see current at the terminals, I guess I am pulling the MC back out to bench test the motor and inspect it?
...and the saga continues, may this be of service to some. I pulled the MC and disconnected the pump motor harness on the motor side with it still bolted onto the pump/mc. Jumped the terminals from the battery and got nothing (!). Removed the pump motor from the assembly and connected it to the battery. It sputtered and began running steadier so I decided to run it for a minute or 2 and it became steady. Did I just break in a motor???
Reinstalled pump motor, bench tested the installed motor (call me paranoid), installed everything back and lo and behold the pump cycles, and I can bleed the rear brakes. And I have brake pressure at the pedal. I also still have all the dash alarms including the high pitched noise. That will be left for tomorrow.
Thanks again, this forum rocks. BTW I have been reading up here over the years, this is my first post.
Reinstalled pump motor, bench tested the installed motor (call me paranoid), installed everything back and lo and behold the pump cycles, and I can bleed the rear brakes. And I have brake pressure at the pedal. I also still have all the dash alarms including the high pitched noise. That will be left for tomorrow.
Thanks again, this forum rocks. BTW I have been reading up here over the years, this is my first post.
Adding to the poll: No , 2002 LX470 with 214k miles
I believe the brake system, except pads and rotors, is original with no indication of a failure. We are the second owner. Bought from PO two years ago at 180k. PO had all service done at a Lexus dealer so I was able to pull up records online. California vehicle the whole time.
This thread is a big wake-up call, and incredibly informative. Thanks to all involved!
Brakes on our LX seem to be performing well, but after going through all 37 pages of this thread, I went out and checked a few things while I still had some daylight.
Pump motor runs for 36 seconds on startup (after 40 pumps of brake pedal with ignition off), and the screws/contacts under the ABS module are bright and shiny with no sign of corrosion evident in the mirror-view. This weekend I'll be adding dielectric grease inside that boot and learning how to flush/change the brake fluid We had an indie Lexus/Toyota mechanic do a flush (among many things) two years ago when we bought the truck. Now the fluid is yellowish and time for me to learn to deal with it!
I believe the brake system, except pads and rotors, is original with no indication of a failure. We are the second owner. Bought from PO two years ago at 180k. PO had all service done at a Lexus dealer so I was able to pull up records online. California vehicle the whole time.
This thread is a big wake-up call, and incredibly informative. Thanks to all involved!
Brakes on our LX seem to be performing well, but after going through all 37 pages of this thread, I went out and checked a few things while I still had some daylight.
Pump motor runs for 36 seconds on startup (after 40 pumps of brake pedal with ignition off), and the screws/contacts under the ABS module are bright and shiny with no sign of corrosion evident in the mirror-view. This weekend I'll be adding dielectric grease inside that boot and learning how to flush/change the brake fluid We had an indie Lexus/Toyota mechanic do a flush (among many things) two years ago when we bought the truck. Now the fluid is yellowish and time for me to learn to deal with it!
edit to add: 99 LX w 140k miles.
Mine went just before getting on the highway, although i didn’t know it at the time. Before getting on the on-ramp, I had to suddenly brake hard, which went fine but I did notice my foot go farther than usual. I though nothing of it and continued onto the highway for a 3 hr drive w wife and little ones.
Finally arriving, on the off-ram which was a downhill slope, i had maybe 20% brakes, going all the way to the floor. I slowed enough and shifted to 2nd and 1st before taking the corner and getting to our destination (Luckily only a couple blocks) using engine brakes and spraying fluid the whole way.
The culprit was a corroded hard line located in the drivers front wheel well- one of the two that are coil-shaped. It had a pin hole in it which was enough.
I ended up paying around $350 for the repair (a nicely fabricated replacement) which isn’t exactly cheap but I needed ASAP, and in hindsight it could have been a whole lot worse.
Mine went just before getting on the highway, although i didn’t know it at the time. Before getting on the on-ramp, I had to suddenly brake hard, which went fine but I did notice my foot go farther than usual. I though nothing of it and continued onto the highway for a 3 hr drive w wife and little ones.
Finally arriving, on the off-ram which was a downhill slope, i had maybe 20% brakes, going all the way to the floor. I slowed enough and shifted to 2nd and 1st before taking the corner and getting to our destination (Luckily only a couple blocks) using engine brakes and spraying fluid the whole way.
The culprit was a corroded hard line located in the drivers front wheel well- one of the two that are coil-shaped. It had a pin hole in it which was enough.
I ended up paying around $350 for the repair (a nicely fabricated replacement) which isn’t exactly cheap but I needed ASAP, and in hindsight it could have been a whole lot worse.
Didn't a audible alarm sound?
When fluid or pressure below predetermined limit, alarm sounds. This alarm can be tested. Just rapidly pump brake pedal with key on. After 5 to 8 full pumps, audible alarm sound!
In on page 19 of this thread working my way through. I inspected the wires going to the brake accumulator? And they look nice and clean. No brake failure, fluid at max line and was when purchased prior to my flush. I never have done the depress pedal 40 to 50 times and counted booster motor run time even when I changed brake fluid. Is this necessary or more of a diagnostic if you have or suspect an issue?
Thank you, I should've done that I recall seeing but thought it was just if you got air in or replaced m/c. I ended up doing it just now 40 pumps, then ign on got 30 seconds till pump stopped. Ran it again right after 40 pumps and just under 32 seconds.
Is it advisable to put dielectric grease on the terminal under the boot? Mine is clean now and if this would help I will do it. This is thr same grease used for battery terminals correct?
You can. Dielectric keeps moisture away. I've talk with the makers of Dielectric grease like CRC. They said the first thing they learn, is the D. grease will not conduct current. They say it would take more than 400 volts to do so. That all it does is keep moisture off and which helps prevent oxidation. Biggest thing is do not overfill reservoir or spill brake fluid on reservoir. It travels down the sides of res and master. Brake Fluid then get into boot of wires and attracts moisture. This is number one cause of booster motor failure IMHO. No 2 is vent at bottom of pump gets clogged/plugged. No 3 is excessive run times, due to pressure lose. Loose motor and loose brakes.
The real biggie in expense. Is screeching with air bubble at front of reservoir. New brake master is then needed. Best protection is frequent flushing, to protect seals. The question is. What fluid is best?
I'm too scared to use anything but oem toyota-thats what I started with and will keep at it!You can. Dielectric keeps moisture away. I've talk with the makers of Dielectric grease like CRC. They said the first thing they learn, is the D. grease will not conduct current. They say it would take more than 400 volts to do so. That all it does is keep moisture off and which helps prevent oxidation. Biggest thing is do not overfill reservoir or spill brake fluid on reservoir. It travels down the sides of res and master. Brake Fluid then get into boot of wires and attracts moisture. This is number one cause of booster motor failure IMHO. No 2 is vent at bottom of pump gets clogged/plugged. No 3 is excessive run times, due to pressure lose. Loose motor and loose brakes.
The real biggie in expense. Is screeching with air bubble at front of reservoir. New brake master is then needed. Best protection is frequent flushing, to protect seals. The question is. What fluid is best?
It's safest. But is not same as what comes in vehicle from factory. That can not be sold in bottle in the USA. The bottle "were" from same Toyota manufacture years ago. Today I do not know who makes the Toyota bottle brake fluid. But it does say engineered by Toyota.
I bought a case last week!
Very interesting - no it did not, just the brake hazard light and I optimistically assumes it was due to the parking brake position sensor.
Had to change my vote yesterday, '99LC with 185K. No signs of booster/accumulator issues until wife picked up kids yesterday and then called me to let me hear the beeping noise. Brake fluid fine. I went to get another car for them to take home, and limped LC home by myself. Absolutely no brake power at first, had to use low gear and putting foot through floor to stop at stop sign, then got on highway. After getting up to highway speed, beeping and lights went away. Braked fine on highway for 9 miles, slowed it down on side road and beeping came back, but braked enough for me to get it into driveway.
Got a full unit on the way from Andy Le, the guy that rebuilds them. I had been wanting to replace it all pre-emptively soon, yet was thinking it'd be overkill. Guess I wasn't unreasonable there, should've done it just a bit sooner.
Got a full unit on the way from Andy Le, the guy that rebuilds them. I had been wanting to replace it all pre-emptively soon, yet was thinking it'd be overkill. Guess I wasn't unreasonable there, should've done it just a bit sooner.
I saw andy le on fb. what does he charage for a rebuild unit?
I have a ‘99, and it was $550, but I think i’ve seen for later years it’s only $450 or so. Not sure what the difference is. That’s for a refurbed master cylinder, pump, and accumulator altogether, with 1 year warranty. He wouldn’t ship a reservoir since they tend to get busted in transit, and said I just need to swap mine on.
For speed, I just gave him an extra $250 for core charge to send me one he had on hand, to be returned whenever I send mine back. I sent him a message yesterday evening on FB, and he had pics of it boxed up and a tracking number this afternoon.
Note about rebuilt Brake Master assemblies..
I just install a rebuilt for a local mud member. I think he bought off ebay, but not sure. Bottom line it leaked, seems from booster pump to motor seal. Return and bough new Toyota OEM.
While unpacking. i noticed; ABS unit had broken plastic at wire housing. The drain for the seal which is also air vent for the pump motor, was clogged. Seems the clog was packing material. I noticed brake fluid in bottom area of master. I thought it was just spillage for shipping with ~1 cup of brake fluid in reservoir. The brake fluid got into control wire boots. I picked-out styrofoam packing foam vent. Cleaned up brake fluid and dried the wire and boots. Also one wire leed bent, keep a wire housing block from seating.
Once installed and bleed:
I test my 4 hard line connection for leaks. NONE.
I pump brake pedal to evaluate accumulator. Took 38 pumps. Which indicates a weak/aged accumulator.
I time booster motor run time. 37 seconds. Indicates slow to build pressure. Likely weak pump motor and accumulator. Likely pressures less than new, like age system would be.
Every screw and even the accumulator was market with blue seal paint. I could not even open motor to inspect or put a new accumulator on that we had. To do anything to the master would have voided the 1 yr warranty.
I just install a rebuilt for a local mud member. I think he bought off ebay, but not sure. Bottom line it leaked, seems from booster pump to motor seal. Return and bough new Toyota OEM.
While unpacking. i noticed; ABS unit had broken plastic at wire housing. The drain for the seal which is also air vent for the pump motor, was clogged. Seems the clog was packing material. I noticed brake fluid in bottom area of master. I thought it was just spillage for shipping with ~1 cup of brake fluid in reservoir. The brake fluid got into control wire boots. I picked-out styrofoam packing foam vent. Cleaned up brake fluid and dried the wire and boots. Also one wire leed bent, keep a wire housing block from seating.
I test my 4 hard line connection for leaks. NONE.
I pump brake pedal to evaluate accumulator. Took 38 pumps. Which indicates a weak/aged accumulator.
I time booster motor run time. 37 seconds. Indicates slow to build pressure. Likely weak pump motor and accumulator. Likely pressures less than new, like age system would be.
Every screw and even the accumulator was market with blue seal paint. I could not even open motor to inspect or put a new accumulator on that we had. To do anything to the master would have voided the 1 yr warranty.
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1998 LC +200,000 miles. Experienced 2 times and it was only a brief second - no warning lights to indicate an issue. Once in Colorado, pressed on brake pedal and went to the floor on a downhill curve decent. Released and pressed again and had normal braking. 2nd time several years later, coming to a stop light, pressed pedal and went to floor. Same thing, released and pedal acted normal I however, ran a red light as I was unable to get the truck stopped in time. Has not occurred in the last 1.5 years.... Got to be the valve on the brake pump but not sure... Would like to make sure it's fixed before we do some Colorado passes in the next year or 2.... Suggestions?