Seeking Knowledge of the Elder Machanics

[Tbishop9]

I see my typo^ Mechanics**

Vehicle: 2002 4runner V6 2WD
Location: Louisiana

Symptoms:

Morning:
5 minutes of beeping along with ABS and brake dash lights coming on while in traffic. It initiated immediately after tapping my brakes.

Evening:
Leaving work. Everything is fine. I start up with no noticeable issues. I put the vehicle in drive, and before I've gone 10', I try to brake, but it is extremely difficult for me to bring my 4runner to a stop (30-40 lbs pressure), and the pedal only falls about an inch (It usually gets close to the floor). As soon as I touched the brake, all lights and the beeping resumed as well. I pulled it back into a parking spot, and the problem has persisted since.

Thought:
I've read up on the booster, check valve, and master cylinder. Current symptoms and tests point to the issue being either the booster or the check valve.

Current Problem:
I started with the check valve since it is a $6 replacement part at my local O'rielly's. I got under the hood, and instead of finding what I expect (A squashed balloon shaped container attached to the master cylinder), I see an assembly of sorts. I can not determine which of these parts acts as the booster, if there is one at all. I have read across a few things mentioning a hydroboost with the ABS system. I have attached pictures of under the hood.

Questions for our Wise Experts:
Am I on the right track, or am I off in left field?
Does my vehicle not have the conventional brake booster?
If it does, where is it??
If it doesn't, does that mean I do not have a vacuum check valve?


I would be extremely grateful for any help thrown my way. I will attempt to respond as quickly as possible to any inquiries!

Thank you for your time!

 

[4Runnermex]

I see my typo^ Mechanics**

Vehicle: 2002 4runner V6 2WD
Location: Louisiana

Symptoms:

Morning:
5 minutes of beeping along with ABS and brake dash lights coming on while in traffic. It initiated immediately after tapping my brakes.

Evening:
Leaving work. Everything is fine. I start up with no noticeable issues. I put the vehicle in drive, and before I've gone 10', I try to brake, but it is extremely difficult for me to bring my 4runner to a stop (30-40 lbs pressure), and the pedal only falls about an inch (It usually gets close to the floor). As soon as I touched the brake, all lights and the beeping resumed as well. I pulled it back into a parking spot, and the problem has persisted since.

Thought:
I've read up on the booster, check valve, and master cylinder. Current symptoms and tests point to the issue being either the booster or the check valve.

Current Problem:
I started with the check valve since it is a $6 replacement part at my local O'rielly's. I got under the hood, and instead of finding what I expect (A squashed balloon shaped container attached to the master cylinder), I see an assembly of sorts. I can not determine which of these parts acts as the booster, if there is one at all. I have read across a few things mentioning a hydroboost with the ABS system. I have attached pictures of under the hood.

Questions for our Wise Experts:
Am I on the right track, or am I off in left field?
Does my vehicle not have the conventional brake booster?
If it does, where is it??
If it doesn't, does that mean I do not have a vacuum check valve?


I would be extremely grateful for any help thrown my way. I will attempt to respond as quickly as possible to any inquiries!

Thank you for your time!

I'm not super familiar with this brake system but I do know runners.
96-00 same booster
01-02 all in one booster, Abs and I don't think it has a check valve.

Sounds like your unit is shot!


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[Unner]

01-02 have no booster. They are an all electronic system. There won't be a check valve on it either, since there is no vacuum assist going to the brakes.

The entire master cylinder thing you pictured there contains the "electronic booster", ABS, and master cylinder. If you are trying to research information on this you will need to look at 01-02 specifically as 96-00 had traditional brake boosters and master cylinders.

Unfortunately it sounds like you might have an issue internally in the master cylinder, which pretty much means it will need replacement. They are fairly expensive used, and ungodly expensive from Toyota. Like thousands of dollars...

Try to do some more research pointed directly at 01-02 4Runners and see what you can come up with before you start throwing parts at it.

 

[4Runnermex]

I have a buddy that has 2 available used from good running 3rd gens. Hmu if you need one


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[Tbishop9]

Yes, my further research brought that to my attention. I am looking to replace the assembly now, and just can't find a good how to. I don't want to get knee deep and realize I need a specialty tool. Thanks for the confirmation!!

 

[Unner]

[MENTION=116470]Tyler James Inc[/MENTION]

Just removed his, he may have his for sale also, not sure. Any pointers on removal Tyler?

 

[01thunder]

Yes, my further research brought that to my attention. I am looking to replace the assembly now, and just can't find a good how to. I don't want to get knee deep and realize I need a specialty tool. Thanks for the confirmation!!

no special tools. disconnect connectors, lines and brake pedal, and 4 nuts above pedal inside and that's it. i've done it a few times. install in reverse and bleed.

 

[JRZEE2000TR4LTD]

And there's this one in the classified section.

http://www.toyota-4runner.org/sale-t4r-items/243708-fs-01-4r-brake-master-assembly-$350-tx.html

 

[SaulG]

ABS Alarm on? What code did the module set??
or you can just replace the whole unit and hope..

 

[Tbishop9]

ABS Alarm on? What code did the module set??
or you can just replace the whole unit and hope..

2 codes:

C0040 Right front wheel speed circuit malfunction
C0141 Left tcs solenoid #1 circuit malfunction

I assumed these were thrown as a result of the booster failure and not the other way around.

 

[SaulG]

Only found codes of 200 and 1200 listed