Where did you get the pump assembly from? Looks to be the cheapest I seen yet.
Poll on total brake failure in 100 series (3 Viewers)
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Where did you get the pump assembly from? Looks to be the cheapest I seen yet.
Local Lexus dealer in Houston. That’s the list price. You may be confusing this pump+accumulator+wire assembly for the larger assembly that includes the master cylinder, reservoir, etc.
While doing some other work today I decided to inspect my control wires and check the booster motor run time. I've got no braking issues and my booster motor run time is spot on. However, my control wires are heavily corroded... There are no signs of the brake fluid reservoir ever being over filled. Brake fluid level is fine as well. A somewhat blurry picture is attached below. Sorry for the poor quality, but getting my phone down there and taking a picture was a challenge.
For future searches, my 03 LX had the ABS/TRAC/Brake lights and alarm come on suddenly. Pedal to the floor with almost no braking pressure. Pulled codes C1223 and C1256. Replaced the brake booster assembly (booster, ABS motor, and accumulator) with a remanufactured OEM unit. Reinstalled using these threads as guides:
If you need to familiarize yourself with the 3 parts that make up the brake booster assembly
How to remove the master cylinder assembly (note that getting to the 4 nuts of the MC are harder in the LX because of the larger VGRS steering shaft assembly, but still doable with hand tools and some angling.
Post 16 in this thread explains how to separate the brake booster from the master cylinder assembly.
How to flush the brake fluid when you're all done. You'll definitely have to flush once, go stomp on the brakes in a field and activate the ABS a few times, then flush again.
I just buttoned my LX back up and am amazed how well the brakes work now, and for $4k less than it would have cost at Lexus, who it seems usually replaces the entire MC assembly for these issues.
Another note - I've seen some people say they could have gotten the brake booster off without removing the master cylinder, others say they did it. I don't see how, but my terminals were corroded and took me three days to get the booster separated from the MC on a bench. Maybe if you've done one of these before and knew all your bolts were in good shape it might be possible. But if your MC is original or you haven't done this job before, just remove the entire MC assembly.
If you need to familiarize yourself with the 3 parts that make up the brake booster assembly
How to remove the master cylinder assembly (note that getting to the 4 nuts of the MC are harder in the LX because of the larger VGRS steering shaft assembly, but still doable with hand tools and some angling.
Post 16 in this thread explains how to separate the brake booster from the master cylinder assembly.
How to flush the brake fluid when you're all done. You'll definitely have to flush once, go stomp on the brakes in a field and activate the ABS a few times, then flush again.
I just buttoned my LX back up and am amazed how well the brakes work now, and for $4k less than it would have cost at Lexus, who it seems usually replaces the entire MC assembly for these issues.
Another note - I've seen some people say they could have gotten the brake booster off without removing the master cylinder, others say they did it. I don't see how, but my terminals were corroded and took me three days to get the booster separated from the MC on a bench. Maybe if you've done one of these before and knew all your bolts were in good shape it might be possible. But if your MC is original or you haven't done this job before, just remove the entire MC assembly.
Unless you've had the vehicle from day one, have known how to top from day one and did inspect level. There is know way to no if over filled at and one time in history. Brake fluid is hygroscopic. Those (your) wires are bad. If it was mine, I'd pull master and carefully drill out the screws. Great care must be taken to not damage the ABS unit when drilling out. Same goes for motor side, if reusing motor. Then replace wire, screws and nuts. This is great time to pull motor apart and inspect.
Great post.
I can see where it is possible to pull motor without removing entire master. But only in cases with no corrosion on wire.
Your wire being corroded. I'm expecting to find the commutator worn out. At 285K the bushes should also be worn, but not excessively so. My money is brush still serviceable and commutator not.
@bpe3 just sent his booster assembly. Thank you so much. That was above and beyond, shipping to me on your dime. I see wires look good. I've not yet pulled it apart. But feel it will be interesting to dig into this one with a good wire. My understated this brake system now works fine. If motor shuts off within 40 seconds, before failure and after R&R. That indicates no pressure loss from leak or sensor issue. Leak can cause loss of pressure. Than motor runs excessively, trying to keep up. Which is another reason a motor would fail early. But in these cases I suspect it could be brushes that fail, as opposed the commutator failure. That is if a motor failure at all. Pumps and accumulator fail also.
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The wires definitely have to be replaced. There was a lot of curd and chunks of rust that came out of the boot when I pulled it off. If money were no option I'd replace the wire and motor both. At this point I'll pull and inspect and see what I've got.
Has anyone made their own control wire? Someone correct me if I'm wrong, but it looks like the wire consist of 4 ring connectors and two strands of wire. I fail to see what makes with worth $200 for a new one.
**Disclaimer: I realize that we're talking about part of a critical system and this probably ins't the place to cheap out. Just asking for the sake of discussion.**
**Disclaimer: I realize that we're talking about part of a critical system and this probably ins't the place to cheap out. Just asking for the sake of discussion.**
Some discussion offline recently if the wire in question is actually anything more or less than a simple harness. Doesn't seem like anything highly specialized and doesn't make any sense why its so frigging expensive other than being hand made by an electrical craftsman in Japan and marked up 20x for sale in USA. I can see that a corroded wire would diminish continuity and possibly affect current draw on the booster motor impacting component life. I'm confident this is the reason for the wire not being reused. So I Ohm tested a new wire against an equivalent length of 14ga stranded copper wire I had laying in my tool box: both delivered .4 ohms. Hmmm nothing special there. The Toyota wire is roughly 10 guage and I think making your own is not out of the question- just be sure to match the correct gauge and length of wire, find the proper terminal ends to fit correctly, install new boots if necessary and do a very good job of sealing off the cable ends from moisture intrusion. Maybe DellCity or DigiKey has all the right components. Lastly getting the polarity of the wires connected properly is probably the most important step. Take pictures during disassembly.
The risk (if there is any) of using home brew wire harness is the potential effect on the abs module or booster motor long term. Expensive experiment if it contributes to early component failure. The wire used on a new wire harness is Yazaki wire (Yazaki Corporation in Japan). Not sure if its special or not but anyone interested can research here: Wire Harness | YAZAKI Corporation
The risk (if there is any) of using home brew wire harness is the potential effect on the abs module or booster motor long term. Expensive experiment if it contributes to early component failure. The wire used on a new wire harness is Yazaki wire (Yazaki Corporation in Japan). Not sure if its special or not but anyone interested can research here: Wire Harness | YAZAKI Corporation
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Brake booster assembly failure 01LX 238K. 83K since last brake service of any kind other than topping a handful of times..
@bpe3 I had a chance to inspect and pull your booster assembly apart. My conclusion based on inspect booster assemble, your stated history of brakes system and service history and your account of what happens during and after failure:
First, replacing booster assemble was a very good call.
I’m sure you had a leak:
Likely leak started ~83K miles ago when you purchased and serviced the brakes. Leak was indicated by your statements. No info on history to draw any conclusion before this time. Likely Motor ran much more often than it would have otherwise, for a longer run times than designed for (2 minute max). This reduced life of motor. It also caused internal damage to armature rubber insulator of booster motor and possible rear seal of pump.
Motor may have stop running due to wet debris ( brake fluid soaked rubber insulator material) interfering with current flow within motor, by getting between brushes and commutator or brush wire at stop. Motor is working at this time. But commutator and bushes are worn much more than I’d expect to see given your mileage and the history you’ve revealed. I do not consider this motor or pump reusable or rebuild able.
Your $225 for install and only $5 charge for brake fluid at and INDY shop. That is cheap! May indicates they did not pull master brake assemble from vehicle. That they R&R the booster assemble in place, which is fine. This means they can get away with only putting a small amount of brake fluid in reservoir and may not have bleed or flushed brake system, which by stated history is way overdue. To flush a system takes much more than $5 of even the cheapest brake fluid.
Recommendation:
Test booster run time after evacuating accumulator (Topping procedure). Make sure motor stop in less than 40 seconds.
Verify that brake system was flushed and bleed. Not only by asking the INDY shop. But also bleed off a little brake fluid from bleeder of each caliper. Inspect color. Is it fresh (clear) like new or old (dark)? Note some murkiness is to be expected unless a supper flushing was done. Reason caliper piston area is very hard to effectively flush without special procedure (super flush). So some old fluid is mixed in caliper most times. So first little amount may be murky. But then clear up as fluid draws from lines.
Flush and bleed if any signs not recently done. (Dark fluid)
FSM Torque on bleeder is 8ft-lbf. I use 10ft-lbf up to 12ft-lbf on used bleeders.
Top and Test booster motor run time again. Make sure still less than 40 seconds. Over 40 most times indicate leak or air in system.
Make sure to blow brake fluid out of bleeders and that all bleeder have good rubber caps on them.
Note: I use high pressure compressed air, then WD40, than HP air again to blow out bleeders.
Rubber from armature. Brake fluid and heat may have broken down rubber wrapping armature..
This may have been a secondary leak that was more recent. Drawing small amounts of brake fliud only while motor running into the motor, damage rubber insulator of armature.
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Continued (Brake booster assembly failure 01LX 238K. 83K)
Screws on motor that hold brake control wire are discolored.
This could be from heat generated during longer than designed limit run times.
Commutator deeply worn, but not through to insulator (no dead spots). Brushes near total worn out. The worst brushes wear I've seen to date!
Multiple sign motor ran excessively, and that it run time was longer than design for also.
Conclusion: Micro leaks over extended period, lead to early failure of motor. Bleeders should be closely inspected.
Screws on motor that hold brake control wire are discolored.
This could be from heat generated during longer than designed limit run times.
Commutator deeply worn, but not through to insulator (no dead spots). Brushes near total worn out. The worst brushes wear I've seen to date!
Multiple sign motor ran excessively, and that it run time was longer than design for also.
Conclusion: Micro leaks over extended period, lead to early failure of motor. Bleeders should be closely inspected.
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I inspected my control wire closer this evening. The end connected to the booster motor looks pristine, like it was put on yesterday. Unfortunately, the end connected to the abs module is horribly corroded, like it's been at the bottom of the ocean for the past 18 years.
I've got no brake issues at all, but I don't want to let this turn into one either. At this point I think @2001LC advice to replace wire and inspect the booster motor is right on. I sure hate to have to pull the master to do it though and have to go through bleeding the brakes, etc.
I've got no brake issues at all, but I don't want to let this turn into one either. At this point I think @2001LC advice to replace wire and inspect the booster motor is right on. I sure hate to have to pull the master to do it though and have to go through bleeding the brakes, etc.
Consider replacing master cylinder plunger kit. It only adds ~$50 and ~30 minutes to the job.
The more often we flush the better.
Just be very careful and take your time if those screws need drilling out.
Start with small bit, work your way up to larger
Just drill off head of screws. Then work nut off and out from behind leads.
The more often we flush the better.
Just be very careful and take your time if those screws need drilling out.
Start with small bit, work your way up to larger
Just drill off head of screws. Then work nut off and out from behind leads.
03LX 285K miles, booster motor failure. Brake wire had corrosion and Commutator of motor had dead spot, brushes good.
Thanks for sending me the pictures of your booster motor. Your motors commutator does look like it has a dead spot. This is what I'm seeing in motors where brake control wires have corrosion, as yours do. It's a tough call with the pictures, as hard to see. Test is to scrape the dark spot. If no copper appears, it's the insulator your scraping. The copper commutator is mounted on a composite insulator. Once that wears through we've a dead spot that a brush may land on, inhibiting current flow through.
Brushes still have enough material remaining to conduct current for some time to come. (brush cage broken during disassembly)
Vent hole was open.
This was one more case were commutator had dead spot from copper being worn to the insulator. This is what I'm seeing when brake control wire has corrosion on it.
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So after no codes or problems from a reputable garage, my wife's LC had complete and sudden brake failure. Thankfully, experience, an an even temperament, and an uphill McDonalds with an empty parking lot was available for her to stop it.
So now I have the old MC assembly sitting in my garage.
Is there anyone that takes these and rebuilds them?
Otherwise, just going to toss it or shipping it back to Toyota Engineering for the lousy design.
Thx
So now I have the old MC assembly sitting in my garage.
Is there anyone that takes these and rebuilds them?
Otherwise, just going to toss it or shipping it back to Toyota Engineering for the lousy design.
Thx
They're not usually rebuild-able.
If you can ship to me, that will be great. Just send me a PM.
I've been asking for these failed master assembly to dissect. I'm looking at cause(s) of failure. The reason I do this, is so I can then give recommendation on how to inspect and prevent.
What I'm finding in most cases of the so called "sudden and complet failure", the one where pedal goes to the floor. Is booster motor failure. All motors fail sooner or later. But when and are external factors causing early failure, is what I hope to learn!
Can I ask:
Years and mileage?
Also, are the brake control wires and screws corroded? (two wire runs from bottom of ABS unit (black box on side of master) to booster pump motor underneath master. Just peel back each of the two boots and look to see if wires and screws are corroded at either end or not)
Post # 506 & 507, @bpe3 shipped to me the booster assembly for dissection.
In Post #510 you see where @dwh13 pulled motor apart and sent me picture. Saved on shipping. He gave me enough info. I then just need a few things physical checked.
If you can ship to me, that will be great. Just send me a PM.
I've been asking for these failed master assembly to dissect. I'm looking at cause(s) of failure. The reason I do this, is so I can then give recommendation on how to inspect and prevent.
What I'm finding in most cases of the so called "sudden and complet failure", the one where pedal goes to the floor. Is booster motor failure. All motors fail sooner or later. But when and are external factors causing early failure, is what I hope to learn!
Can I ask:
Years and mileage?
Also, are the brake control wires and screws corroded? (two wire runs from bottom of ABS unit (black box on side of master) to booster pump motor underneath master. Just peel back each of the two boots and look to see if wires and screws are corroded at either end or not)
Post # 506 & 507, @bpe3 shipped to me the booster assembly for dissection.
In Post #510 you see where @dwh13 pulled motor apart and sent me picture. Saved on shipping. He gave me enough info. I then just need a few things physical checked.
I have been through the majority if not all of this thread but do not see a reference for a "how to parking brake inspection and rebuild", did I miss that somewhere or are most people referencing the FSM at that point?
I also would like to reiterate a question and see if it's normal or not:
Usually when I start the vehicle and drive it, the brakes are "soft" or "normal" feeling. But if I press the brake, let go, then press it again (or do this procedure two/three times), then it gets significantly stiffer and harder to press (still brakes just fine, it's just the pedal is significantly stiffer than the previous time I depressed it a few seconds ago).
I've got other Toyotas that don't do anything like this (same braking feel/force all the time).
Is this symptomatic of a problem?
I just had the brake fluid flushed a couple weeks ago as well if that could have anything to do with it (but I had it done right after I bought it, so I don't really know if it was doing this before the flush or not).
Also — how often should you hear that little motor running? I hear it when I start the vehicle and it goes away (which is normal from what I've read), but I'll hear it while I'm driving intermittently (not all of the time, but today for instance: I started the vehicle -> drove 10 feet to a stop light w/ a soft (what I'd consider normal) brake pedal -> drove through the light, and broke again to make a right into a parking lot, and the pedal was a LOT stiffer -> as I was pulling the vehicle into a parking spot, I could hear the motor running again. This entire drive was about 90 seconds). I probably applied brake pressure 6-12 times throughout from driving there, slowing down for other cars, go over speed bumps, etc
What do you guys think?
Usually when I start the vehicle and drive it, the brakes are "soft" or "normal" feeling. But if I press the brake, let go, then press it again (or do this procedure two/three times), then it gets significantly stiffer and harder to press (still brakes just fine, it's just the pedal is significantly stiffer than the previous time I depressed it a few seconds ago).
I've got other Toyotas that don't do anything like this (same braking feel/force all the time).
Is this symptomatic of a problem?
I just had the brake fluid flushed a couple weeks ago as well if that could have anything to do with it (but I had it done right after I bought it, so I don't really know if it was doing this before the flush or not).
Also — how often should you hear that little motor running? I hear it when I start the vehicle and it goes away (which is normal from what I've read), but I'll hear it while I'm driving intermittently (not all of the time, but today for instance: I started the vehicle -> drove 10 feet to a stop light w/ a soft (what I'd consider normal) brake pedal -> drove through the light, and broke again to make a right into a parking lot, and the pedal was a LOT stiffer -> as I was pulling the vehicle into a parking spot, I could hear the motor running again. This entire drive was about 90 seconds). I probably applied brake pressure 6-12 times throughout from driving there, slowing down for other cars, go over speed bumps, etc
What do you guys think?
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Hey all!
My entire master cylinder assembly was just replaced by a local shop after the booster died on my old one (2000 LC, 231k miles). Rather than use a new OEM assembly ($$$!!!), the shop found a used assembly from another 2000 LC (no idea how many miles were on it, which sucks). The brakes now seem fine, and I hear the booster motor come on every 4-5 pushes on the brake pedal (which seems normal), but it looks like the shop overfilled the brake fluid reservoir.
Based on what I've read here, this is definitely NOT a good thing - I'm assuming I need to remove the extra fluid, correct? Also, I've been driving the rig this way for about the last 400-500 miles before I noticed that they overfilled the fluid - any issues with this?
I've got a limited 12-month, 12,000 mile warranty on the used MC assembly, so if something is wrong, I'd rather have the shop fix it sooner rather than later!
Any and all help would be greatly appreciated! Thanks!
My entire master cylinder assembly was just replaced by a local shop after the booster died on my old one (2000 LC, 231k miles). Rather than use a new OEM assembly ($$$!!!), the shop found a used assembly from another 2000 LC (no idea how many miles were on it, which sucks). The brakes now seem fine, and I hear the booster motor come on every 4-5 pushes on the brake pedal (which seems normal), but it looks like the shop overfilled the brake fluid reservoir.
Based on what I've read here, this is definitely NOT a good thing - I'm assuming I need to remove the extra fluid, correct? Also, I've been driving the rig this way for about the last 400-500 miles before I noticed that they overfilled the fluid - any issues with this?
I've got a limited 12-month, 12,000 mile warranty on the used MC assembly, so if something is wrong, I'd rather have the shop fix it sooner rather than later!
Any and all help would be greatly appreciated! Thanks!
You'll find some threads or buried within threads stuff on E-barke. Search the 100 section. It's a simple mechanical set up. With a FSM as your guide they are easily rebuilt on rust free rigs. Rust can really make job more challenging.
Brake pedal should feel the same most all the time. I say "MOST" due to when vehicle sits, say overnight, the pressure does bleed down a little. Then when you turn IG key to on, the pressure builds back up (booster motor runs).
I'd test booster motor run time, first thing. Read direction on reservoir on "how to top brake fluid". After topping, first time IG turned to on, time how long booster motor runs. If over 40 seconds you may have a leak or air in system. If under 40 seconds you likely need a master cylinder rebuild. One other thing I've not personally seen is accumulator goes bad.
Yes remove excesses fluid.
Used is okay. But like all motors it will have wear, so life expectancy is not as if new. Here's the thing. I disassemble used motor before installing. I make sure the commutator, brushes, bearings and insulation all look good. Then I install with new brake control wire, screws and nuts just as FSM call for.
As I suggested above test booster motor run time.
Also peel back the boots and inspect condition of brake control wire (Wire Harness). If wet with brake fluid clean off with electric contact spay cleaner safe for plastic too dry.
Any corrosion on brake control wire, I recommend replacing wire and inspecting booster motor. Motor side of wire has a boot as does ABS side. Below shows just ABS side:
Bottom of ABS unit (black box) on side of brake master.
Inspection of brake lines is important also!
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Will send you a PM later this week with some pics of the MC.
Her truck is an 04 with 265K on the clock. She just loves and babies her truck, so we had to invest in a new MC assembly. Thanks
