Faint buzzing sound behind steering wheel/Brakes?

D

daugherty83

New member
On startup and occasionally at a stop, I can hear a buzzing sound, almost like a an electric motor turning on would be the best way to describe it. Sounds like a pump or such. It is located behind steering wheel, through the firewall. I know the brake booster and such is located in this position in the engine bay. Anyone ever notice this before? Brakes are good, and am having no trouble. Just a weird little noise. Noise will come on, and stay for a minute max and then click off. Almost sounds like when the trac control kicks in when spinning a tire in wet grass.
 
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That would make some sense, but like i said it is on the drivers side not the passenger side, and the radio is off, hence no power antennae raising.
 
Does it do it on start up? Like it comes on, then pauses for a little, then starts again? If so that might be the fuel pump i think.
 
I think I have the same sound! Does it sound like a buzzing sound then a click like something turned off? It has been driving me crazy trying to figure out what it is, and of course it only does it when I'm alone! :redbrick:
 
daugherty83 said:
On startup and occasionally at a stop, I can hear a buzzing sound, almost like a an electric motor turning on would be the best way to describe it. Sounds like a pump or such. It is located behind steering wheel, through the firewall. I know the brake booster and such is located in this position in the engine bay. Anyone ever notice this before? Brakes are good, and am having no trouble. Just a weird little noise. Noise will come on, and stay for a minute max and then click off. Almost sounds like when the trac control kicks in when spinning a tire in wet grass.
Click to expand...
Unlike most cars that use a vacuum booster for power brakes the later 4 runners have an electric motor and a reservoir built into the master cylinder. You are probably hearing this motor refilling the reservoir for the next time you press the brakes. One nice feature of this system is that as long as the ignition is on you always have power brakes even if the engine has stalled.
 
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drmorbius said:
Unlike most cars that use a vacuum booster for power brakes the later 4 runners have an electric motor and a reservoir built into the master cylinder. You are probably hearing this motor refilling the reservoir for the next time you press the brakes. One nice feature of this system is that as long as the ignition is on you always have power brakes even if the engine has stalled.
Click to expand...

Sounds spot on
 
drmorbius said:
Unlike most cars that use a vacuum booster for power brakes the later 4 runners have an electric motor and a reservoir built into the master cylinder. You are probably hearing this motor refilling the reservoir for the next time you press the brakes. One nice feature of this system is that as long as the ignition is on you always have power brakes even if the engine has stalled.
Click to expand...

Would this be the same for my '01?
 
JKloeker said:
Would this be the same for my '01?
Click to expand...
The way to test if you have it is to shut off the engine while rolling, turn the key back on but don't start the engine, and try the brakes. You should have an unlimited number of power assisted stops.
 
Concur with the master cylinder/brake booster suggestion.

Comes on nearly every time you brake. Open up the hood and have a buddy push down on the brake pedal when the truck is on and in park...it'll cycle on and off. It buzzes pretty noticeably.

Do you feel the vibration from the booster coming through the brake pedal?
 
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Mine does this on occasion, I htought it had something to do with ABS usually only when I first start up reverse out then stop I hear it and then if I hit a real quick pot hole while breaking I hear it again.
 
This sounds exactly like what it is doing. I don't feel any pulsating through the pedal, just the faint noise of a motor. Guess this is normal. It was just odd to hear. Thanks guys.
 
Master Cylinder Noise

5 Years later...I just wanted to follow up on this post seeing that I am having the same issue it sounds. Rather than post a new thread, thought I might seek another response.

I just bought a cream puff of an 01' SR5.

I noticed that same motorized noise except I have a few more specifics.

1. It happens specifically when the brake pedal has been pressed 5 or 6 times
while driving or stopped.
2. The motorized noise is right where the master cylinder sits beyond the
firewall, lasts for 5 or 6 seconds and clicks off somewhere down near the
passenger side firewall.
3. Filled up reservoir (which was a little low) to max. After a couple days of
driving, brake fluid is now noticeably above max about 1/8 of an inch.

I understand that this feature is motorized and has its benefits but would rather not hear it go off every 5 to 6 brake applications. Any suggestions?
 
Master Cylinder Noise

5 Years later...I just wanted to follow up on this post seeing that I am having the same issue it sounds. Rather than post a new thread, thought I might seek another response.

I just bought a cream puff of an 01' SR5.

I noticed that same motorized noise except I have a few more specifics.

1. It happens specifically when the brake pedal has been pressed 5 or 6 times
while driving or stopped.
2. The motorized noise is right where the master cylinder sits beyond the
firewall, lasts for 5 or 6 seconds and clicks off somewhere down near the
passenger side firewall.
3. Filled up reservoir (which was a little low) to max. After a couple days of
driving, brake fluid is now noticeably above max about 1/8 of an inch.

I understand that this feature is motorized and has its benefits but would rather not hear it go off every 5 to 6 brake applications. Any suggestions?
 
I bought a 4Runner 2007 a year ago, but this was a salvage vehicle. I was thinking the noise was part of the damage, but neither the mechanic was able to tell if the sound will stop if we replace the ABS pump.

The 4Runner works great, just the annoying noise is what we hate the most.
 
motags said:
5 Years later...I just wanted to follow up on this post seeing that I am having the same issue it sounds. Rather than post a new thread, thought I might seek another response.

I just bought a cream puff of an 01' SR5.

I noticed that same motorized noise except I have a few more specifics.

1. It happens specifically when the brake pedal has been pressed 5 or 6 times
while driving or stopped.
2. The motorized noise is right where the master cylinder sits beyond the
firewall, lasts for 5 or 6 seconds and clicks off somewhere down near the
passenger side firewall.
3. Filled up reservoir (which was a little low) to max. After a couple days of
driving, brake fluid is now noticeably above max about 1/8 of an inch.

I understand that this feature is motorized and has its benefits but would rather not hear it go off every 5 to 6 brake applications. Any suggestions?
Click to expand...

After reading several of these threads, it may be just how it is. I was trying to solve the same issue.
 
daugherty83 said:
On startup and occasionally at a stop, I can hear a buzzing sound, almost like a an electric motor turning on would be the best way to describe it. Sounds like a pump or such. It is located behind steering wheel, through the firewall. I know the brake booster and such is located in this position in the engine bay. Anyone ever notice this before? Brakes are good, and am having no trouble. Just a weird little noise. Noise will come on, and stay for a minute max and then click off. Almost sounds like when the trac control kicks in when spinning a tire in wet grass.
Click to expand...

I have the same thing. Happens even with no traction control....
 
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