Brake Booster Assembly With Master Cylinder Replacement (1 Viewer)

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May 4, 2013
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2004 LC with 190K miles. Recently the "dying seagull" screeching sound is coming back. Based on the discussion on this forum, replacing the whole assembly is the only solution. If I read correctly, the screeching sound is caused by a deteriorated O-ring inside the master cylinder body. When it is under high pressure, it can not properly seal tube and let the fluid pass. That is the cause of the screeching sound. There is no known way to just replace the O-ring inside the master cylinder body.

I would like to keep the truck as long as possible. Thus I decide to bite the bullet and purchases a new assembly. After brake is very important for safety. Luckily the price for the whole assembly is much lower than before now. Used to be $2500 and up. Now it is around $1500. You can buy it online at little bit cheaper price. But I decide to go with my local dealer ship just in case. They are able to work out a price that is closer to the online price. Never hurt to haggle the price.

For 2004 LC part number: 47050-60043

I try to follow the step shown on this video (). It is great video. But I found that it is not necessary to take part the whole bottom panel. Just take out the ABS control module will give enough space to work on the 4 nuts. top left, bottom left and top right nuts are easy after ABS module is removed. Bottom right nuts is a little bit challenging. Needs a swivel adapter and extension, but still not too hard.

Over all it is pretty easy job.

Happy wrenching


1645242818110.png

Heavily corroded.

1645242921597.png

1645242956181.png


Old and new

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1645242759319.png
 
Is there anyone buying old brake booster assembly? Old one is not always make that noise. May be restorable.
Will ship in factory package box.

1645243224801.png


Add little bit silicon to prevent any water penetration. Not sure if silicon will work here.
 
This is what I am thinking next: My Master pump has no issues but who knows at 240K miles.

It is important to check the cold start electric pump run time (30 sec or less) and the frequency of it turning on afterwards. If it runs longer than say 35 sec and frequent afterwards , REPLACE the ACCUMULAOR ASAP before the ABS motor get killed by running more often than necessary.


98-2000 models havea ovel shape wire plug for the pressure sensor and others have a trangular shape wire plug (See last picture on 1st post). The presurre switch is located right above the green cap in Evap hose.
 
Is there anyone buying old brake booster assembly? Old one is not always make that noise. May be restorable.
Will ship in factory package box.

maybe the guy who rebuilds them in Oregon?
 
With the price of the brake assembly with master cylinder getting lower, I think this should become a maintenance item once the truck hit 200K mile. After all, brake is the most important safety feature. $1500 is still high, but it came down from $2500, it is on correct trend now. Toyota, for the safety of all LC 100 owner, please drop the price even further.
 
2004 LC with 190K miles. Recently the "dying seagull" screeching sound is coming back. Based on the discussion on this forum, replacing the whole assembly is the only solution. If I read correctly, the screeching sound is caused by a deteriorated O-ring inside the master cylinder body. When it is under high pressure, it can not properly seal tube and let the fluid pass. That is the cause of the screeching sound. There is no known way to just replace the O-ring inside the master cylinder body.

I would like to keep the truck as long as possible. Thus I decide to bite the bullet and purchases a new assembly. After brake is very important for safety. Luckily the price for the whole assembly is much lower than before now. Used to be $2500 and up. Now it is around $1500. You can buy it online at little bit cheaper price. But I decide to go with my local dealer ship just in case. They are able to work out a price that is closer to the online price. Never hurt to haggle the price.

For 2004 LC part number: 47050-60043

I try to follow the step shown on this video (). It is great video. But I found that it is not necessary to take part the whole bottom panel. Just take out the ABS control module will give enough space to work on the 4 nuts. top left, bottom left and top right nuts are easy after ABS module is removed. Bottom right nuts is a little bit challenging. Needs a swivel adapter and extension, but still not too hard.

Over all it is pretty easy job.

Happy wrenching


View attachment 2930069
Heavily corroded.

View attachment 2930070
View attachment 2930071

Old and new

View attachment 2930072

View attachment 2930066

In your second picture, I see an overfilled reservoir.

I like "Timmy the toolman's" videos. I'm sure after doing more of these, he'll streamline as you have.

But seems most everyone, keeps missing one small detail. How to properly top reservoir.

Toyota was concerned enough this be done correctly, it's embossed on the brake reservoir.

Brake reservoir (1).JPG
 
maybe the guy who rebuilds them in Oregon?
Do you know his user name? I think I saw his post in the big 46 page sticky top post. But unable to go through 46 pages again to find his username.
 
In your second picture, I see an overfilled reservoir.

I like "Timmy the toolman's" videos. I'm sure after doing more of these, he'll streamline as you have.

But seems most everyone, keeps missing one small detail. How to properly top reservoir.

Toyota was concerned enough this be done correctly, it's embossed on the brake reservoir.

View attachment 2931693
I followed "Timmy the toolman's" videos. Before taking apart the assembly, he asked customer to pump the brake for 40 time to release the pressure in the container. I pumped >30 times until the brake down to floor. In this case, all the brake fluid in the high pressure container came back to the reservoir, thus it looks overfilled.

What I didn't follow is the part he take off the whole sub panel to gain access to the left top bolt. It certainly make it easy to do that if every thing is out of the way. I just don't want to take off so many things apart. I am 100% sure, I will break some clips along the process. But you have to put your body into some wired position to gain access to all the bolts. It is indeed challenging sometime. Not as challenging as changing the CV Axle:)

Hope I didn't screw up anything, I followed his video very carefully.
 
I pumped >30 times until the brake down to floor. In this case, all the brake fluid in the high pressure container came back to the reservoir, thus it looks overfilled.
It doesn’t just look overfilled, that means it IS overfilled. You do not add fluid until after pumping pedal 30+ times and it drops to the floor.
 
By chance can anyone confirm if this is the same part #47050-60043 for a similar year LX?
Thanks in advance
 
Do you know his user name? I think I saw his post in the big 46 page sticky top post. But unable to go through 46 pages again to find his username.

I think this is a link to his ebay store
 
Replaced both front brake lines
  • 90947-02F29 FRONT LEFT​

  • 90947-02F28 FRONT RIGHT​

Very easy to swap them out.

However, a lot of brake fluid came out while unscrewing the flare connector. The brake line is probably dry.

Try to bleed the brake system again. This time I noticed the brake motor runs longer than 40 seconds.

Is it normal for brake abs motor running longer than 40 seconds when the brake line is dry?

@2001LC

 
Yes. Why! because motor runs until X pressure achieved. Air takes more energy to compress, than brake fluid.
 
Yes. Why! because motor runs until X pressure achieved. Air takes more energy to compress, than brake fluid.
Thanks for confirming that. I was so scared when the abs motor still running after 40 seconds. I thought I messed up big time.

I used 7 quarts of Toyota brake fluid. More than usual, but I want to flush the brake line as much as possible.

Hope this brake assembly will last another 100k mile
 
2004 LC with 190K miles. Recently the "dying seagull" screeching sound is coming back. Based on the discussion on this forum, replacing the whole assembly is the only solution. If I read correctly, the screeching sound is caused by a deteriorated O-ring inside the master cylinder body. When it is under high pressure, it can not properly seal tube and let the fluid pass. That is the cause of the screeching sound. There is no known way to just replace the O-ring inside the master cylinder body.

I would like to keep the truck as long as possible. Thus I decide to bite the bullet and purchases a new assembly. After brake is very important for safety. Luckily the price for the whole assembly is much lower than before now. Used to be $2500 and up. Now it is around $1500. You can buy it online at little bit cheaper price. But I decide to go with my local dealer ship just in case. They are able to work out a price that is closer to the online price. Never hurt to haggle the price.

For 2004 LC part number: 47050-60043

I try to follow the step shown on this video (). It is great video. But I found that it is not necessary to take part the whole bottom panel. Just take out the ABS control module will give enough space to work on the 4 nuts. top left, bottom left and top right nuts are easy after ABS module is removed. Bottom right nuts is a little bit challenging. Needs a swivel adapter and extension, but still not too hard.

Over all it is pretty easy job.

Happy wrenching


View attachment 2930069
Heavily corroded.

View attachment 2930070
View attachment 2930071

Old and new

View attachment 2930072

View attachment 2930066

Hey Txslg,

I had a couple of questions about the brake booster job you did. I recently replaced mine and took it to a local Indie shop. Unfortunately, I'm currently living in a country that never sold any Land Cruisers in the local market and my indie shop has no experience in bleeding the brakes for a 100 series (2000 LC). I even took it to the Toyota dealership and they said that they couldn't do the work. (Long story short, everything is genuine Toyota save the City Racer brake booster and the dealership did not want to touch the car.) They claimed that their computer wouldn't be able to connect (eye roll). My question for you and anyone that may have the answer is: The brakes work good with a manual bleeding but I hear the brake booster pumping constantly when I depress the brakes. Is that normal? I never noticed any noises before the brake booster replacement. When the pump activates, it's only for 3-7 seconds but I do notice it now. Secondly, my indie shop told me that air bleeding is not necessary. Either manual bleed or air bleed. He asked a Toyota/Lexus tech friend who told him that. I tend not to believe him as I've read here on Mud along with your Timmy video that the air bleed via Techstream should follow the manual air bleed. I'm in the process of getting a Techstream set up going but so far no luck. Anhy help/advice would be greatly appreciated. Thanks!
 
The brakes work good with a manual bleeding but I hear the brake booster pumping constantly when I depress the brakes. Is that normal?
If the motor runs every time you press the brake pedal, then you still have air in the system. But it should periodically run to maintain pressure in the system. Mine kicks on after every 4 or 5 brake applications, which is normal.

Secondly, my indie shop told me that air bleeding is not necessary. Either manual bleed or air bleed.
I think you’re referring to electronic/ABS bleeding as “air bleeding”, and if so, there are a couple of different ways to do it, but your shop is wrong - it does need to be done. Techstream is the surefire way to do it, through other options exist.
 
If the motor runs every time you press the brake pedal, then you still have air in the system. But it should periodically run to maintain pressure in the system. Mine kicks on after every 4 or 5 brake applications, which is normal.


I think you’re referring to electronic/ABS bleeding as “air bleeding”, and if so, there are a couple of different ways to do it, but your shop is wrong - it does need to be done. Techstream is the surefire way to do it, through other options exist.
Thank you JunkCrzr89! I am still trying to sort out a techstream install. For the time being, what are alternatives to bleeding the electronic/ABS ? I’m trying to square this away to avoid other potential catastrophe like burning out my new brake booster pump. Thanks!
 

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