Brakes ...... Overdue write-up. (1 Viewer)

[2001LC]

Yes it's over filled. Likely so much so, it came out cap while parked overnight.
How much it's above full line (after key 40 pumps) is approximately how much needs to be removed.
You can then turkey-baster (draw) out some from reservoir, down to max line.
Or
Use the same method we do to flush fluid from system:

1. Attach hose to REAR bleeder, going to catch can. Reservoir holds, a little more than 1 qt., when not over filled
2. Turn IG Key on. No need to start engine.
3. Hold brake pedal down (do not pump or release brake pedal with bleeder open).
4. Open REAR bleeder.
5. Fluid pumps out until bleeder closed (or IG key turned off or brake pedal released or no fluid in reservoir). Warning: do not run booster motor, longer than 2 miniates!
6. Close bleeder when you've removed enough fluid. (Do not reuse fluid).

Now recheck level, by following direction embossed on reservoir. Add to full line from fresh bottle. I use only Toyota brake fluid. I'll bet Dealership used cheap bulk.

Meet "My Little Friend". The spring loaded shower pole.

Hose and catch can.
Reservoir holds about qt.

Cap bleeders after drying

 

[Jimthom]

Why do you remove excess fluid ( above Full line) by bleeding through the rear brake?
Could it not be removed with a baster from the fluid reservoir itself? This seems simpler.

Incredible write up. Thank you.

 

[2001LC]

Why do you remove excess fluid ( above Full line) by bleeding through the rear brake?
Could it not be removed with a baster from the fluid reservoir itself? This seems simpler.

Incredible write up. Thank you.

Edit: I stand corrected. I looked at a brake reservoir today, while doing a flush. The level cover sits low enough under cap , one could use a baster to draw just about to the full line.

Nope, baster to large and rigid!. Look at post #45 cut away pictures of reservoir. There's an internal cover over fluid level sensors in the way, just below cap area.

Although there is a small opening towards the front. One could use a very thin hose and suck some out, which I did this "once". To draw most all fluid out.

But really, just letting pump do the work, catch at rear bleeder is easy. It's how we flush.

 

[2001LC]

Yes, 47050-60041 has the flat/oval ABS connector.

47050-60042 has the triangular connector.

Why do you remove excess fluid ( above Full line) by bleeding through the rear brake?
Could it not be removed with a baster from the fluid reservoir itself? This seems simpler.

Incredible write up. Thank you.

Edit: I stand corrected. I looked at a brake reservoir today, while doing a flush. The level cover sits low enough under cap, one could use a baster to draw just about to the full line.

Nope, baster to large and rigid!. Look at post #45 cut away pictures of reservoir. There's an internal cover over fluid level sensors in the way, just below cap area.

Although there is a small opening towards the front. One could use a very thin hose and suck some out, which I did this "once". To draw most all fluid out.

But really, just letting pump do the work, catch at rear bleeder is easy. It's how we flush.

I stand corrected. I looked at a brake reservoir today, while doing a flush. The level cover sits low enough under the cap, one could use a baster or syringe to draw just about down to the full line.

The one I was working on today, was overfilled. Fluid color not bad, so recently flushed. I re-flushed, as beings it was overfilled, indicates proper procedure not followed. Which I then assume; accumulator likely not flushed, non Toyota brake fluid used and likely ABS not bleed. It had non OEM bleeder caps on one side and none on other. Rear brake pad wear indicators missing and aftermarket pads & rotor. It scream flush with Toyota brake fluid, to me.

 

[Jimthom]

I stand corrected. I looked at a brake reservoir today, while doing a flush. The level cover sits low enough under the cap, one could use a baster or syringe to draw just about down to the full line.

The one I was working on today, was overfilled. Fluid color not bad, so recently flushed. I re-flushed, as beings it was overfilled, indicates proper procedure not followed. Which I then assume; accumulator likely not flushed, non Toyota brake fluid used and likely ABS not bleed. It had non OEM bleeder caps on one side and none on other. Rear brake pad wear indicators missing and aftermarket pads & rotor. It scream flush with Toyota brake fluid, to me.

I understand now. I think you did mention this some where up above., that one could not get a baster in deep enough.
So, maybe one could.
But your reason for bleeding through the rear makes sense.
Thanks.

 

[Rhetoric]

Amazon product ASIN B00MPQ8RBG
I used this to pull out enough fluid from my overfilled reservoir. Worked great.

 

[kevgentile]

Hey 2001LC, have a question for ya since you've been deep inside these ABS modules.

My '99 LX is parked out in front of our shop as I'm waiting on a replacement ECM to repair a previous owners mess up, and haven't had time or the weather to jump into the master cyl/ABS module due to a leak at the reservoir grommets.

I pulled the main power connector to the unit to stop it from cycling since the fluid is low and I found brake fluid that has accumulated inside the connector. These are weatherproof connectors so fluid shouldn't have found its way from the outside in, but I guess anything is possible.
I haven't been inside one of these unit yet but assume that the unit is leaking thru the inner terminals of the pump.
Have you come across this?

Cheers mate!

 

[2001LC]

In OP, I mention how brake fluid gets the wires and flow along them into the boot(s). Most often, the fluid comes out the reservoir cap due to overfilling.
Actually, it's 99.99% impossible for the fluid to leak from inside the black plastic (outer halve of the ABS unit) out the wire block. I busted one ABS apart once. It appears to be solid plastic, molded around the metal skeleton that terminates as leads in wire housing blocks.

It's very rare to see leaks, from grommets. Unless reservoir has been off.

Most times, the leak come from between the black ABS unit and master cylinder at seals of aluminum block sandwich between them..

I'd, clean spotless and watch for first recurrence of leak.

• If grommets, replace them.
• If leak from ABS. I'd replace the whole master assembly with booster.

 

[2001LC]

ABS unit (AKA black box & sliver block on side of master).

ABS unit, is not meant to be a serviceable part. But I want to go ahead and show some of it's workings. It's attach to masters body with 6 bolts. Between the master and sliver block is a seal plate. There is 3 round screens, fixed in the silver block. These screens, especially the one in upper right corner of below picture can become clogged. I see this clog, when I find reservoir stained. Staining in reservoir, indicate fluid not timely flush and turn black. It may also indicate a mix of various off the shelve brake fluids added Over time, brake fluid absorbs moisture from the air and darkens. Moisture in fluid reduces boiling point of fluid, resulting in brake fade and soft pedal feel. It's also, damaging to the seals. IMHO, non Toyota fluid, is also damaging to the seals. Perhaps it would be more accurate, to say. Not good for the seals. As it's possible, Toyota fluid has a seal conditioner. But that is, pure speculation on my part. Which speculation, is based on a TSB, from the 2005-07 (not 100 series) brake master seal recall. Which specifically cited off the shelve (non Toyota brake fluid), added and damaging seals.
Clogged screen

Comparison screen, not clogged.

If we remove the seal (non pressure) cover on the black box. Here's what we see. Again not meant to be a serviceable part.

Is we separate the ABS black box from silver block, we coils of the valves.
The block box, seems to be. The wire housing blocks circuits board.

 

[2001LC]

Here's the silver blocks, coils removed (busted apart).

 

[2001LC]

Basically.

If any components inside of a master has failed, or function compromised. It's very likely other components are also compromised or not far behind. Best course of action. Even booster motor or accumulator failing. When we consider age of all 100 series master today. Is replace the whole brake master assembly, with new.

The biggest concern, is loss of brake fluid pressure.
But we can also have malfunction, that can lockup a single caliper. Which depending on driving condition at the time, can be deadly.

IMHO these so called: Rebuilt Brake Master, are JUNK and Dangerous. No one, to this date, has proven: They can actual rebuild the master and ABS unit. They are only, cleaning up exterior and restoring booster assembly. Which on most, is just a rebuilt booster motor.


I don't think I've shown this before, dealing with reservoirs. Which some of the rebuilt master may have.

Cleaning reservoir, not a good idea. We'll likely, just make it function worst. Its front camber then may drain down slower.

If you see a brake master reservoir stained or not. Watch its front camber, to see is slower than it's other cambers to drain/draw down. That is just one more bad sign, when grading a brake master. If clean and slow, it may have been cleaned, or something added to fluid.

This was a stained reservoir, that was clean inside. See the one camber in front, has more fluid. Which would be seen, when booster motor pumps fluid back into accumulator drawing fluid (down) from reservoir. That one camber, slowly drain down and to level of other cambers. So even though this reservoir looked good (stain free), indicating a health of master free of debris and weak seals. It was not.

 

[ShenValley100LC]

Ok, so I'm have having issues with brake master cylinder but its seems slightly different than what I've in the threads and almost like I have of an electrical issue maybe that may or may not be solved by replacing the whole master cylinder.

(for context its a 1999 LC with 572,000 miles)
This past Tuesday on a fairly warm morning my wife turned the car on, the brake motor came on normal but after 20 or so seconds got a bit louder with a bit of screeching/whistling sound (not quite as loud or constant as the screaming seagull sound I've heard on others videos) and the abs and brake light go on and off about 1.5 seconds but no alarm. Later that day I pumped the brakes 30 times and turned the key to on (without starting) and got the same intermittent screech and slowly blinking lights, if I tap the pedal during this it cuts off the noise from the brake motor/accumulator and the lights but then they come back. I tried unplugging, cleaning, leaving them disconnected for a day, and reconnecting some of the abs plugs. No change, other than after a minute or two the motor cycling normal and going screeching loud--it then stops entirely and the ABS and BRAKE light illuminate but no alarm sound.

I have checked and there are no bubbles and splashing of fluid when the screeching happens or when the motor/booster is on. It seems more like an issue with the high pressure switch. I also audibly hear a clicking (tick/tock) sound that seems almost like it is coming from the fuse box/or maybe abs box. None of the fuses look blown, but not sure about the relays. I only have a scan gauge II and a $25 code reader from amazon and neither show any codes. I'm guessing if there is ABS sensor/solenoid/fuse issues it would show up on these devices? Do I need techstream or just a better code reader? I did replace the passenger side CV on saturday, maybe I knocked the abs sensor?

I did have an issue at the end of December where on a road trip with the family the flare nut going into the three way junction on top of the rear was leaking and I had a shop cut it, reflare, and flush the brakes, and it does look like they overfilled the reservoir (and most likely not with toyota fluid). It looks like it may have over flowed since then and maybe the hygroscopic issues are affecting the wiring for the master cylinder. If that's the case it would seem replacing the whole MC assembly would take care of it.

I'm trying to figure out how I can be sure the master cylinder vs an electrical problem elsewhere (rain egress in the a pillar getting on wiring, abs sensor, fuses/relays, etc)?

 

[Jack90210]

Basically.

If any components inside of a master has failed, or function compromised. It's very likely other components are also compromised or not far behind. Best course of action. Even booster motor or accumulator failing. When we consider age of all 100 series master today. Is replace the whole brake master assembly, with new.

The biggest concern, is loss of brake fluid pressure.
But we can also have malfunction, that can lockup a single caliper. Which depending on driving condition at the time, can be deadly.

IMHO these so called: Rebuilt Brake Master, are JUNK and Dangerous. No one, to this date, has proven: They can actual rebuild the master and ABS unit. They are only, cleaning up exterior and restoring booster assembly. Which on most, is just a rebuilt booster motor.


I don't think I've shown this before, dealing with reservoirs. Which some of the rebuilt master may have.

Cleaning reservoir, not a good idea. We'll likely, just make it function worst. Its front camber then may drain down slower.

If you see a brake master reservoir stained or not. Watch its front camber, to see is slower than it's other cambers to drain/draw down. That is just one more bad sign, when grading a brake master. If clean and slow, it may have been cleaned, or something added to fluid.

This was a stained reservoir, that was clean inside. See the one camber in front, has more fluid. Which would be seen, when booster motor pumps fluid back into accumulator drawing fluid (down) from reservoir. That one camber, slowly drain down and to level of other cambers. So even though this reservoir looked good (stain free), indicating a health of master free of debris and weak seals. It was not.
View attachment 3553249

Can you explain a little bit more about the front chamber, and why it would be bad if it were to appear to have a higher level than the others? Is it because the booster motor is running for longer than it ought to?

 

[2001LC]

Ok, so I'm have having issues with brake master cylinder but its seems slightly different than what I've in the threads and almost like I have of an electrical issue maybe that may or may not be solved by replacing the whole master cylinder.

(for context its a 1999 LC with 572,000 miles)
This past Tuesday on a fairly warm morning my wife turned the car on, the brake motor came on normal but after 20 or so seconds got a bit louder with a bit of screeching/whistling sound (not quite as loud or constant as the screaming seagull sound I've heard on others videos) and the abs and brake light go on and off about 1.5 seconds but no alarm. Later that day I pumped the brakes 30 times and turned the key to on (without starting) and got the same intermittent screech and slowly blinking lights, if I tap the pedal during this it cuts off the noise from the brake motor/accumulator and the lights but then they come back. I tried unplugging, cleaning, leaving them disconnected for a day, and reconnecting some of the abs plugs. No change, other than after a minute or two the motor cycling normal and going screeching loud--it then stops entirely and the ABS and BRAKE light illuminate but no alarm sound.

I have checked and there are no bubbles and splashing of fluid when the screeching happens or when the motor/booster is on. It seems more like an issue with the high pressure switch. I also audibly hear a clicking (tick/tock) sound that seems almost like it is coming from the fuse box/or maybe abs box. None of the fuses look blown, but not sure about the relays. I only have a scan gauge II and a $25 code reader from amazon and neither show any codes. I'm guessing if there is ABS sensor/solenoid/fuse issues it would show up on these devices? Do I need techstream or just a better code reader? I did replace the passenger side CV on saturday, maybe I knocked the abs sensor?

I did have an issue at the end of December where on a road trip with the family the flare nut going into the three way junction on top of the rear was leaking and I had a shop cut it, reflare, and flush the brakes, and it does look like they overfilled the reservoir (and most likely not with toyota fluid). It looks like it may have over flowed since then and maybe the hygroscopic issues are affecting the wiring for the master cylinder. If that's the case it would seem replacing the whole MC assembly would take care of it.

I'm trying to figure out how I can be sure the master cylinder vs an electrical problem elsewhere (rain egress in the a pillar getting on wiring, abs sensor, fuses/relays, etc)?

25 yrs and 500K miles, it's time!

That does sound like fluid passing a seal. Your reservoir was to dirty and you did not stay focused on front long enough. For me to see if any bubbles, while sound happening. Pressing brake pedal helps heat/expand the seal, so it holds pressure. IMO it is the seal losing pressure. This will get worst and motor will run long and longer duration, to keep pressure up. Motor will fail, as it is only designed to run short duration. As such, brakes will fail when no pressure (motor fails to run pump).

Replace the the booster assembly w/brake master (the whole brake master).

 

[2001LC]

Can you explain a little bit more about the front chamber, and why it would be bad if it were to appear to have a higher level than the others? Is it because the booster motor is running for longer than it ought to?

It's a sign screens in reservoir are slow/clogged. In a new master, the level equalizes very fast. So fast, hardly notice the chambers level differences.

It indicates fluid not properly cared for during master history in vehicle. Such as not regularly flushing and mixing of various brake fluids. This is also, a clue of health of seals. As the gunk (solids), is abrasive to seals. It can also dry out seals, resulting in excessive shrinkage.

This reservoir was worst. I was cleaning, and stop short of cleaning all, to get this picture. Anyone think, this is a good thing in a brake master!

If the reservoir screens gunky. So is the screen(s) in to ABS unit. This can also get into valves in ABS unit.

Clogged ABS screen

Clear ABS screen

 

[2001LC]

Can you clean a reservoir. Some post in mud say yes, with alcohol. But that does nothing for seal and ABS. A dirty stained reservoir is a clue, as to heath of master.

 

[Jack90210]

This is exactly the reason why I flush a quart of brake fluid through my entire system at least once a year. Thanks for posting that, and for being the one who first drew my attention to the need to do so (in other threads). You're a great resource, @2001LC .

 

[2001LC]

BTW: I only use Toyota brake fluid and flush about 1.8 qts through.

Best is 2 qts., when doing caliper work. To get 90% out of caliper, the typical flush & bleed does not. I flush. Then open bleeder and press piston, forcing fluid out one caliper at a time. Then bleed.

 

[ShenValley100LC]

Alright, I was almost done installing the new abs master cylinder unit and the threads on the flare nut of the brake line that goes to the far drivers side port of the M/C are messed up, it wont go in straight and pops out. Was thinking of just cutting it at the flare putting a new nut and re-flaring. But seeing some mixed signals on forums and not much information. Seems its a double (inverted) flare and flare nut is 10mx1.0. Is there a part number for the hard brake line or has anyone been fine just re-flaring it themselves?

 

[2001LC]

If flare nut threads of pipe actually damaged. You can also replace the hard line, save brain damage.

I "may" have listed, flare nut size here: If not, measure diameter and count threads. Any flares nuts you may end up getting, test fit first. Most you find at parts store that are metric, are the correct size and count.

Installing SS Braided Brake lines, Flare nut stuck in pipe!

Ok this I've not seen this before. What appears to be a factory installed, brake hose from main pipe to differential pipe flare nut is stuck on female end. While removing the two upper rear brake hoses, the flare nut of one hose was hard to turn, as if cross thread. But now that threads are...

forum.ih8mud.com

Also get the metric flaring maker kit, not SAE. If you go that route!

It's the masters soft threads, that tend to get damage. Get picture of threads, zoom in. See which and if damaged.

Sometimes, threads of flare nut get damaged, Form hit on threads of flare nut. While muscling out & in master. To this end, I rubber cap flares nuts as I pull from master. I also use the carboard, that comes in top of OEM brake masters box. As a shield, between master & all hard lines as I install master in engine bay.

If flare nut threads or female threads of master, not to badly damaged. A thread chase may fix them.

But, check a few things first:

Often times, it's a matter of getting flare nut line-up with female threads of master.
Also make sure flare nut, spins easily on pipe. A drop of oil on pipe, helps.
Always thread flare nut, all the way on be hand. Pulling outward on pipe, as nearing bottoming. Helps center pipes female flare to male in master.

Good luck.