Brake master Accumulator Screeching and reservoir bubbling at same time. Toyota Lexus
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- Опубликовано: 21 окт 2024
- The brake warning dash lights and alarms were coming on & off. In this 2000 Toyota 100 series Land Cruiser. 4 ABS codes C1210, C1223, C1252 and C1256. Booster motor run times were varying from; non stop, 57, 48 to 38 seconds. Brake control wire had corrosion. Reservoir was overfilled. All caliper bleeder caps missing. Rear bleeder frozen in. Caliper brake fluid of rear caliper very nasty looking. Screeching was being heard, and bubbles seen come up in reservoir at same time. Screeching was occurring often more when cold. As system used/test repeatedly, by pumping brake 40 times to evacuate accumulator with IG switched OFF (topping procedure), and then IG switch ON to hear pump motor run and time how long it runs. Alarms and Screeching became less frequent the more test repeated or brake used. I believe this improvement is due fluid warming up seals within system. Also of noted, it took 38 pumps of brake pedal to evacuate accumulator, before pedal drop to floor. After repairs; ~25 or less pumps of pedal to evacuate accumulator, run time test ~29 second, no screeching, no bubbling, no brake alarms or warning dash light. Codes cleared and did not return.
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Had a similar thing happen. The brake fluid reservoir cap was loose. Check cap tightness and seal. It seems to be loosing pressure and therefore constantly has to recharge.
Cap on this one was on, with arrow on cap pointed to back (wrong). Embossed on reservoir is OPEN & CLOSED, which arrow should point to. I did correct, and it was on tight. But these caps could be off during test. Cap keeps air/moisture out and fluid in. The reservoir itself is not a pressure vessel. There are 3 grommets at bottom of reservoir into master, an a hose from master to pump. These along with cap, also are not pressure fittings. If pressure was built up in reservoir, those points would leak very badly. The hard red line with flare nut(s) just bellow accumulator going to master is a pressure line/fitting. That red line delivers pressure into master cylinder from accumulator.
This entire master brake assembly (actuator/pump/motor) have been the bane of my existence. It seems like they were meant to fail close to if not right at 20 years.
I find master assembly can go out at very low or can last to a very high mileage. I firmly believe 90% of failure boils down to improper maintenance. I've not actually ever seen the "master cylinder" go bad. The master cylinder itself does benefit with a master cylinder kit (plunger & seals). Making sure fluid is kept regularly flushed (clear and low moisture) can really aid in longevity of seals of plunger. I've a Master assembly in a 20 year old 100 series Lexus LX470, with over 350K miles on the odometer, it works fine. That said, what I do see, is booster motor failure as number 1 cause of brake failure. Without motor failure, we've no booster pressure. Motor accounts for 90% of brake "master assembly" issue. In 8 out of 10 motor failures, I find the brake control wire has corrosion, and resistance through wire is higher then ones with good wires. I've no double the wire that are corroded, do damage to the motor. Brake fluid gets into it's boot(s) of wire attracting moisture. This is due to overfilling brake reservoir. 1 out of 10 motor failure is due to excessive long run times (over 2 minutes). This is due to pressure loss, most often associated with leaks or weeps in systems that goes undetected. 1 out of 20 is vent to motor clogged. Motor then sucks in fluid from low pressure side of pump.The other 1 out 20 motor failure is from bushes worn out. They last a very very long time, in a properly maintained system that does not have excessive use. The other 10% of brake failure (Which do not typical cause a sudden loss of brakes and give lots of warnings). 50% accumulator failure. 30% brake line failure. 10% is the ABS unit (black box on side of master) 10% is someone driving and braking so long past the wear indicators of pads long after they've have been scrapping/squealing to alert. They burn/grind through the piston until it comes out past the caliper cylinder seal and all fluid is lost.
@@memy895 Man this should be a video or thread by itself. Sad it is hidden here !!
@@mikezzz7885 Just FYI here is a writeup on ih8mud forums from MeMy about this specific issue, pretty much what you were alluding to having a thread by itself ;) forum.ih8mud.com/threads/brakes-overdue-write-up-on-brakes.1230968/
Mine failed at 20 years. I went to self serve junkyard and replaced motor/accumulator for $60.
@@encinobalboayou’re fortunate to have found one at the junkyard
I do my posting in ih8mud. RUclips is just where i store these videos. I will be writing up 100 series brakes one day, in a dedicated thread there. Over last 5 years I've learned a lot about them. But still more to learn. Not even Master Toyota certified mechanics know this stuff. Why?. They do one thing and with good reason. They replace master assembly at first sign of any issue with them. I saw 7 master under a masters' bench last week. He said those were from just last week jobs. None were from 100 series. I've also learned a few mistake Dealership are make with brake servicing. That is another story!
So what does that screching means?
@@_svs_ IMHO: Brake fluid passing a seal under high pressure. Internal leak that just gets worst, and can not be fixed (seal can't be replaced). It will get worst, causing pressure lose. Booster motor will run excessively and fail prematurely.
@@memy895 thanks bud
@@memy895 is complete replacement the only way to go? My 2000 is making the same noise. No lights on the dash yet.
@@jenkinsinlihue Yes! You can just but master. The booster assembly (Motor, control wire, pump, accumulator) can be bought later if needed. Check pricing.
I have the same problem with the overcharging and screeching sound. What wire did you find corrosion on to fix this issue?
The corroded wire does not fix the issue. It's the brake control wire. It goes from bottom of ABS unit (black box on side of brake master assembly) to booster motor attached to bottom. It was just and observation during inspection. I'm finding the booster motor fails prematurely when the wire is corrode. We believe the screeching is from failing accumulator (gold cylinder). But some times we replace the accumulator or even entire booster assembly, the condition clears up. Other times does not totally cleared up. Seals get old cold and hard and or aging pressure switch(s) may also play a roll here. One reason most shop and all Dealership will only replace the entry assemble is cascading effect. You replace one old tired part and other don't hold up well to the increased pressures. So the vehicle come back and customer just knows, they paid good money and still have issues.
ME MY thanks for your reply. I have done some testing on mine and believe the pressure switch may be faulty when cold which is not cutting the motor out when full pressure is achieved. Have you experienced seeing the pressure switch internally? I am tempted to remove the cover from the black abs module to see inside but unsure if I will see anything.
@@mathewtonks1501 I have taken apart the black ABS unit on the master, they have no replaceable parts. I don't know of anything that can be done with these ABS units. I have heard the ABS unit does have pressure switches internally, but don't know anything other than replacing the unit that can be done. I am seeing the same, in above 2000 100 series Toyota. We have already R&R the booster accumulator assembly (booster motor/pump/accumulator), R&R master plunger/seals, flushed and bleed. After all this was done, everything worked as it should until cold outside air temp (OAT). Then pump will not shut down. It only happens when OAT is below 15F, and nothing other then OAT getting above 32F corrects this. If OAT below 32F above say 15F, we get brake alarms until brake system seals warm up by use. We are not sure why pump not shutting off. But alarms are often heard coming on, then going off in older brake system as seals shrink with cold OAT.. I'm going to replace the pressure switch that is threaded into the front on the master assemble. I hope this solve the issue of pump not stopping below 15F. In this 100 series we also think the caliper seal leaking when cold. So if replacing switch does not work, we'll rebuild calipers also. If nether correct issue we will be replacing the master which comes with the ABS unit.
@@mathewtonks1501 I am experiencing something similar; booster doesn't screech no where to the extent it does in the video, but the motor runs for about a minute on start-up and towards the end of the cycle a very minor screech can be heard and then it stops. Then it's all fine through the day, coming on at every 3 or 4 brake pushes for about 4 seconds.
And it occurred once where the motor didn't stop running for 4 minutes and the alarms came on, and then it went away a minute later,
I am also suspecting pressure sensor/switches.
Let me know if you have replaced the pressure sensor and if that fixed the problem and I'll change mine :)
What is that cylinder with the yellow label on it. I ordered a new brake master cylinder for my 01 GS430 and it came with everything except that cylinder. Bought the master cylinder for local mechanic to install in hopes of fixing the brake pedal sinking down..
Accumulator. It does come with Master, when the whole master (Brake master with booster assembly) is orders from Toyota/Lexus.
Bubbling?
It looks like it's just vibrations causing the fluid to ripple.
Booster motor
So mine when I first turn on after sitting for hours does that noise where it sounds like it turns on but never the screech at the five second mark of the video it lasts about 10 seconds then shuts off is that normal it’s a 2001 4Runner 4x4 ? It’s just on initial start up but goes away just curious if that’s normal and again never has it screeched as it did on the 5 second mark of the video
It is normal for booster pump motor to run after sitting or when pedal depressed.
That is the sound of weak accumulator pump dc motor The logic tries to work it until it sees proper pressure build up at the accumulator but it won't however it will keep running to limp you back home killing it self on the way
@Mountain man life junkyard/ebay you can't go wrong with that
@Mountain man life you can diy its fairly simple lookup YT for toyota HBB
@@Airman.. do you mind if I ask? The assembly = motor + accumulator + master cylinder? In most cases, the trouble is caused by either motor or accumulator? Why people say actuator? I'm not to locate the actuator...
@@reocam8918 you can test the accumulator by watching system pressure via a data pid or external gauge while car is not running, it's main purpose is to store line pressure when the dc motor is not running, there is no actuator in the system just the motor and a small hydraulic pump attached to it, 90% of the problems is a weak pressure caused by failing motor carbon brushes resulted slow spinning pump
I have a 01 4runner and on startup, the motor runs for just under a minute, and very rarely for more (if cold and parked outside for a few days), and towards the end of the run on startup, there is a hissing sound that can be heard behind the brake pedal
But after that, the motor runs for 4 seconds or so every third or fourth push of the pedal,
Is that all normal?
I think it's normal. The actual run time is key. But with older units seems on cold mornings we do get longer run time (over 40 sec) than spec of 30 to 40 seconds. The hissing sounds, if from brakes, is not normal.
@@memy895 Do you happen the know which component in the system produces that screech? is it the motor or does it come from the accumulator?
And the bubbles appearing at 1:08 with the screech, does that mean the system suddenly drew air or encountered an air bubble somewhere and once it's gone, it technically shouldn't happen?
Bump@@amirgarekani5352
Is the accumulator sound between 0:04 and 0:05 normal?
No. That sound is indication, that an un-replaceable seal, is allowing fluid past at high pressure. That Master needs replacing!
My GX 470 sounds like that for about 15-30 seconds on startups then the sounds goes off. My owner manual states that a brake buzzer sounding is normal on startups. What do you think?
@@memy895 Thanks for the reply
@@josetorresgrajales4429 I only work on 100 & 200 series. So can not say what's normal for a GX. But that sound in video is not good, from any Toyota motorized brake master. If pressure drops causing motor to run too long or continuously, it will burn up brushes & commutator of motor sooner than later..
To be clear. Brake booster motor will run when IG key turned on. This is system building pressure activating booster motor to run pump. You'll hear motor and pump run, as you do in video. But sound ~5 second in video is not normal.