Thanks for the replies to my sons 4runner question yesterday! I think we're much better prepared to solve our serpentine belt/idler/tensioner issue.

The next big problem with this rig is the brakes. The woman we purchased it from has not driven the truck for the past year. She had the whole brake master cylinder unit replaced- I think she said it cost $1200? But she said shortly after the repair the warning signal came back and had no low/no brake fluid in the master cylinder. Someone told her she had blown a brake line. I filled it up last night, and the pedal doesn't push to the floor nor is the master cylinder seeming to lose fluid. But the warning signal is blaring, and I have all the the Brake-VSC Trac-ABS lights on. I know the Master cylinder was replaced because the old part is in a box in the back. Was thinking about going through and bleeding all the brakes this afternoon to see if that solves the problem? Your advice would be really helpful! My son is so excited about his new truck

Thank you
1sam16

Bleeding the rear brakes is done with engine on, Crack open bleeder valve and have brake pedal depressed and it will pump a steady stream of fluid out. Front brakes are done the "normal" way. However, since you have a dry(?) MC there may be a bit more involved. Someone with that experience will chime in I'm sure.

There are several pieces/parts of the ABS/master cylinder assembly, please post a few photos of the old part so we know exactly what pieces/parts were replaced.

The truck is parked across town until we can limp it home. Going back over this afternoon/evening. We'll take some pictures... but the unit that was replaced looks like the picture I hopefully attached

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A picture of his truck.

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The engine doesn't need to be on to bleed the rear brakes. Open a rear bleeder valve (I do one side at a time and attach a rubber hose to the valve and have a water bottle to catch draining fluid), turn the key to ignition (but don't start) then depress the brake pedal. Be sure the MC is full when you start and be careful not to run it dry. Have someone watch it or check it every 5-10 seconds, fill it up when needed. If you hold the pedal down too long the alarm will go off. Stop, turn the key off, check the MC level, start again.

As said, the front lines are bled the normal way.

Nice, I like the color
Looks like SR5 wheels but Limited running boards. No hood scoop so not an SE.

Here's my 2004 SE:

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Nice truck! My son Gabe would've loved to have a 4runner with a hood scoop... Maybe we'll stumble onto one in the future? But first, we need to get it to stop/replace some idlers/tensioner pulleys, and do a quick patch on the frame. The previous owner kept a file on all the things that she had fixed. We're glad she got as much done as she did but unfortunately, I think she got ripped off- lots of high dollar parts replaced.

Thanks for all your help!

perhaps the replaced unit is bad?.
start the truck and have someone depress the brakes, while you hold the silver cylinderical part /motor in your hands...if it pulses/actuates....thats a clear sign that the brake assy is halfgood, if it doesnt actuate. check the abs brake fuse in the fuse bay if its blown - i think its a 40 amp fuse.

OK- here is the picture of the brake master cylinder unit that was replaced-
the whole unit was replaced. The core is in the trunk... maybe if some parts are bad I could swap with parts off of the core? She seemed to think that they replaced much more than was needed for whatever problem she was having.

Once the battery is charged back up I'll turn the vehicle on depress the brake and check for vibrations indicating the brake booster is working.

I did find at least one area that brake fluid is leaking... hoping this is helpful in diagnosing the problem and moving towards a fix.

Again thanks,
1sam16

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BTW- It did look like the leak was at the coupling. Looks like theres a shroud that has come apart on the RT/leaking coupling?

Does the removed master cylinder have the black ABS control ECU on the driver's side?

This is why I wanted to see a few photos of the one they removed, it's not what's on the new one but what is still on the old one that will tell us what all was replaced.

That fluid leak could well be your issue.

Got it- heading over one more time tonight- will get a couple pictures of the old unit. I shot that leaking area with some PB blast and will tear it apart and see whats up.

OK- here are the pictures-

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Followed ur directions- the brake unit does vibrate/buzz but not necessarily in conjunction with brake pedal use. With the ignition on, the unit would vibrate/shut off/vibrate/shut off in a pattern. I made a quick video, but can't seem to upload it.