Brakes Chirp when pressurizing

Moist

Moist

Member
The cold weather is coming and that means my brakes get a little funky again.
I've been doing a slow rebuild of the brakes one piece at a time. The dealership rebuilt all four incorrectly and didn't replace the rotted brake lines. I've got some good horror stories about them but this isn't the post for them.

One of the weirdest things that it's been doing since it visited the dealership maybe 5 years ago is this:

When the brakes pressurize (whether from usage or just pumping fluid into the system on a cold start), there's a chirping/grinding sound that happens near the end of a pumping cycle.
I'll grab a recording of it after classes today, but it is starting to get a little bit concerning. The sound is coming from the pedal area and the brake reservoir area, I can even feel a vibration through the pedal when it grinds (although it's just feeling the difference in vibration from it pressurizing).
I have bled the brakes several times, and it doesn't seem to have fixed it. I've even flushed all fluid more than once. New (ish) brake lines.

I'm thinking I'm losing a brake booster or a master cylinder, but I wouldn't know. I haven't seen anything that matches the sound or description yet.

Shes a 2003 SR5 V8.
 
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I have an '03 Limited and I too am getting some brake master cylinder concerns. Mine feel soft, I've bled them a couple of times but they get no better. I live close to "The Car Care Nut" so I'm going to pay him a visit and ask his opinion.
 
Moist said:
https://www.youtube.com/watch?si=NGcSIl7PKDiJlzrD&v=OOLFcLWf_ks&feature=youtu.be
Here's the sound.
I don't have a soft pedal feel, or at least it's hard to tell with warped fronts. Doesn't feel very soft.
Click to expand...

I agree it sounds like the electric motor is failing.

If the master cylinder/ABS assembly is original, I would bite the bullet and replace the entire assembly, I replaced the complete assembly on mine last year even though I could of just replace the motor/pump assembly but with almost 200,000 miles on the original unit I want to have it done right and not worry about it for the rest of the vehicle's life and I needed it working correctly without further failure as it's my daily driver.

I found the best price/shipping combo at ToyotaPartsDeal, I did the install myself which save a chunk of labor, it's not all that hard to do, it took me about 1 1/2 hours.
 
Moist said:
https://www.youtube.com/watch?si=NGcSIl7PKDiJlzrD&v=OOLFcLWf_ks&feature=youtu.be
Here's the sound.
I don't have a soft pedal feel, or at least it's hard to tell with warped fronts. Doesn't feel very soft.
Click to expand...

Here was mine. It was much worse than yours. Was also getting holiday lights and the dreaded brake failure continuous chime.

https://www.youtube.com/watch?v=EbhZzsfan6o

The second time my brakes failed, the junkyard pump stopped working and the pedal went hard. Braking was difficult but not gone so M/C was OK. Luckily, I was close to home. I had a spare pump/accumulator assembly (another $50 JY "score") and was back in one the road in 1/2 a day.

Anyways, if your MC was gone, pedal would go to floor with no brakes. You can do this my way which is replace pump/accumulator for cheap or the right way which is replace complete hydro-boost assembly.
 
AuSeeker said:
I agree it sounds like the electric motor is failing.

If the master cylinder/ABS assembly is original, I would bite the bullet and replace the entire assembly, I replaced the complete assembly on mine last year even though I could of just replace the motor/pump assembly but with almost 200,000 miles on the original unit I want to have it done right and not worry about it for the rest of the vehicle's life and I needed it working correctly without further failure as it's my daily driver.

I found the best price/shipping combo at ToyotaPartsDeal, I did the install myself which save a chunk of labor, it's not all that hard to do, it took me about 1 1/2 hours.
Click to expand...

1.5 hours! I struggled mightily getting the cotter pin seated, lol. The rest was easy.
 
SocalSam said:
1.5 hours! I struggled mightily getting the cotter pin seated, lol. The rest was easy.
Click to expand...

To be fair that 1 1/2 hours didn't include me sitting behind the steering wheel thinking about it for about 1/2 hour, I always procrastinate when I don't really want to do a job then bite bullet and jump on a project and get it done. LOL
 
SocalSam said:
Here was mine. It was much worse than yours. Was also getting holiday lights and the dreaded brake failure continuous chime.

https://www.youtube.com/watch?v=EbhZzsfan6o

The second time my brakes failed, the junkyard pump stopped working and the pedal went hard. Braking was difficult but not gone so M/C was OK. Luckily, I was close to home. I had a spare pump/accumulator assembly (another $50 JY "score") and was back in one the road in 1/2 a day.

Anyways, if your MC was gone, pedal would go to floor with no brakes. You can do this my way which is replace pump/accumulator for cheap or the right way which is replace complete hydro-boost assembly.
Click to expand...

Oh Yikes! That's really bad. At least it seems to be the same sound. That video is very helpful.

I can say I'm very familiar with that brake alarm and brake failure. Although both for different reasons than this. :wacko:

I need to see if I can find a junkyard with a 4runner somewhere in the surrounding states, they're harder to come by. A Toyota dealership is willing to part with a whole assembly for about 3 grand but that's stupid high.

Otherwise it's going to be finding a lot of diagrams and reading up, if it is that motor or some lubrication failure I wonder if I can do something to "repair" it or force it to last longer. Reading some old threads I get the consensus these parts are very hard to remove from the assembly.

This car is on it's last legs and just needs to survive a year or two more before it gets put away for restoration.
 
Moist said:
Oh Yikes! That's really bad. At least it seems to be the same sound. That video is very helpful.

I can say I'm very familiar with that brake alarm and brake failure. Although both for different reasons than this. :wacko:

I need to see if I can find a junkyard with a 4runner somewhere in the surrounding states, they're harder to come by. A Toyota dealership is willing to part with a whole assembly for about 3 grand but that's stupid high.

Otherwise it's going to be finding a lot of diagrams and reading up, if it is that motor or some lubrication failure I wonder if I can do something to "repair" it or force it to last longer. Reading some old threads I get the consensus these parts are very hard to remove from the assembly.

This car is on it's last legs and just needs to survive a year or two more before it gets put away for restoration.
Click to expand...

Pump/accumulator is common to other early 2000's Toyota and Lexus. You can find compatibility list in ebay of all places. For example:

https://www.ebay.com/itm/2868752935...ydroboost+pump+and+accumulator&epid=658863249

When at the JY, you can test the pump with 12V. It should run smoothly and the bearings should sound quiet. If pump sounds like it is laboring, keep looking. You won't be able to test accumulator. The Shade Tree believes separating pump from accumulator will introduce other problems and should not be done unless necessary. I got mine from a 2004 Lexus GS with accident damage.
 
Moist said:
Oh Yikes! That's really bad. At least it seems to be the same sound. That video is very helpful.

I can say I'm very familiar with that brake alarm and brake failure. Although both for different reasons than this. :wacko:

I need to see if I can find a junkyard with a 4runner somewhere in the surrounding states, they're harder to come by. A Toyota dealership is willing to part with a whole assembly for about 3 grand but that's stupid high.

Otherwise it's going to be finding a lot of diagrams and reading up, if it is that motor or some lubrication failure I wonder if I can do something to "repair" it or force it to last longer. Reading some old threads I get the consensus these parts are very hard to remove from the assembly.

This car is on it's last legs and just needs to survive a year or two more before it gets put away for restoration.
Click to expand...


That $3000 price is a high "List" price, the entire assembly an be ordered online from some dealers for $1363, still high but not full price.

47050-60080 Genuine Toyota Brake Booster Assy, W/Master Cylinder)
 
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