Buzzing/Vibration noise behind dash while driving

[SC_4RunnerSC]

So long story short. Took my car out to a gun range in the middle of the woods and the roads were bad (bumpy). Car drove amazing there l, but here is my concern.

On the way back, I was going highway speed (60-70mph) and all of a sudden I heard this buzzing/loud vibration behind the steering wheel dash. Came on randomly and lasted maybe 5 seconds? Happened probably 15 times in a time frame of 30mins

I looked up the whole master cylinder/brake booster thing and my brakes weren’t giving me any trouble/no Christmas lights came on. Didn’t have one single problem with brakes at all on the way home. And this noise is only at 60mph or higher-haven’t heard it under that speed

So I’m thinking maybe the bumps and holes on the road maybe loosened something? Or what would y’all believe may have caused this. 05 v8 with 157,000 miles

I can’t really justify the whole $3000 for a small part and labor. I absolutely love my 4Runner but damn is everything expensive to fix on it. Any thoughts are much appreciated! Id rather play it safe than sorry since I’m driving an hour on the highway again on Sunday-don’t want the master cylinder to randomly fail on me

 

[AuSeeker]

So long story short. Took my car out to a gun range in the middle of the woods and the roads were bad (bumpy). Car drove amazing there l, but here is my concern.

On the way back, I was going highway speed (60-70mph) and all of a sudden I heard this buzzing/loud vibration behind the steering wheel dash. Came on randomly and lasted maybe 5 seconds? Happened probably 15 times in a time frame of 30mins

I looked up the whole master cylinder/brake booster thing and my brakes weren’t giving me any trouble/no Christmas lights came on. Didn’t have one single problem with brakes at all on the way home. And this noise is only at 60mph or higher-haven’t heard it under that speed

So I’m thinking maybe the bumps and holes on the road maybe loosened something? Or what would y’all believe may have caused this. 05 v8 with 157,000 miles

I can’t really justify the whole $3000 for a small part and labor. I absolutely love my 4Runner but damn is everything expensive to fix on it. Any thoughts are much appreciated! Id rather play it safe than sorry since I’m driving an hour on the highway again on Sunday-don’t want the master cylinder to randomly fail on me

I can't say what your vibration is...unless it's one of the climate control temp/zone actuators....but from what you describe I wouldn't think it's the master cylinder, the buzzing from the master cylinder is the electric motor that powers the booster pump, if any part of the booster system is going bad it wouldn't be apparent/heard until you press the brake pedal and the pressure drops or when you first start the vehicle, so running at 60 MPH the booster system shouldn't be activating unless you have a major leak in the booster system which would be very apparent at any time, there are 3 major parts to the booster system, the electric motor, the pump and the accumulator, what usually goes bad is either the motor wears out and can no longer power the pump, the pump goes bad but this is rare, or the accumulator stop holding pressure, the accumulator is the cheapest to replace but make sure to use a new o-ring so it seals properly, the electric motor is not cheap but can be rebuilt or get a rebuilt one for around $400 to $500, when the motor is almost worn out it will usually be noticeably nosier than normal followed at some point by not coming on at all, the pump is also not cheap but it's strange that many times you can find the pump/accumulator together cheaper than you will pay for just the pump.

if you have the booster system fail you will still have brakes but you will not have a full brake pedal and you will have to use considerable force to to get any braking action, I would advise everyone to start practicing on how to stop your T4R in case of the booster system failure or complete brake failure...to do this you need to slow down well ahead of time when possible and then use down shifting to slow down, then to come to a complete stop use what little brakes you have or the parking brake...but keep in mind that you will need to push the parking brake pedal again to release it, so push the parking brake pedal down until you get noticeable braking action and then slightly push it again to activate the release mechanism but don't let up on the pedal just release pressure or push it harder to brake more. but keep in mind you will not have much stopping power with just the parking brake but if it working properly it will eventually stop you at very slow speed.

DO NOT use the parking brake to slow down unless there's no other option at that moment only use it after downshifting all the way to first gear, downshifting can slow you down to 5 to 10 MPH when done correctly, only shifting into first when under 15 MPH or so then use the parking brake to stop and then get off the road ASAP.

I had to do this about 3 years ago on Thanksgivings night returning home after visiting with my daughter in Charleston, luckily there was very little traffic on the roads, I had a complete brake failure, I had a front caliper steel brake line break because where it attaches to the steering arm the bolt broke and the line was slightly flexing until over time it finally broke, no parts stores were open due to the holiday so I ended up driving all the way home..about 90 miles only using slowing down, downshifting and the parking to come to a stop, it was not all that hard to do and not scary if you know how to use this method but only use it in an emergency, just takes practice and timing, this wasn't a new thing for me because my father taught all of his kids how to do this in a emergency so I have use this method and practiced it many time in my life (I'm old as dirt by the way), it's something I think everyone should know how to do!!

 

[SC_4RunnerSC]

I can't say what your vibration is...unless it's one of the climate control temp/zone actuators....but from what you describe I wouldn't think it's the master cylinder, the buzzing from the master cylinder is the electric motor that powers the booster pump, if any part of the booster system is going bad it wouldn't be apparent/heard until you press the brake pedal and the pressure drops or when you first start the vehicle, so running at 60 MPH the booster system shouldn't be activating unless you have a major leak in the booster system which would be very apparent at any time, there are 3 major parts to the booster system, the electric motor, the pump and the accumulator, what usually goes bad is either the motor wears out and can no longer power the pump, the pump goes bad but this is rare, or the accumulator stop holding pressure, the accumulator is the cheapest to replace but make sure to use a new o-ring so it seals properly, the electric motor is not cheap but can be rebuilt or get a rebuilt one for around $400 to $500, when the motor is almost worn out it will usually be noticeably nosier than normal followed at some point by not coming on at all, the pump is also not cheap but it's strange that many times you can find the pump/accumulator together cheaper than you will pay for just the pump.

if you have the booster system fail you will still have brakes but you will not have a full brake pedal and you will have to use considerable force to to get any braking action, I would advise everyone to start practicing on how to stop your T4R in case of the booster system failure or complete brake failure...to do this you need to slow down well ahead of time when possible and then use down shifting to slow down, then to come to a complete stop use what little brakes you have or the parking brake...but keep in mind that you will need to push the parking brake pedal again to release it, so push the parking brake pedal down until you get noticeable braking action and then slightly push it again to activate the release mechanism but don't let up on the pedal just release pressure or push it harder to brake more. but keep in mind you will not have much stopping power with just the parking brake but if it working properly it will eventually stop you at very slow speed.

DO NOT use the parking brake to slow down unless there's no other option at that moment only use it after downshifting all the way to first gear, downshifting can slow you down to 5 to 10 MPH when done correctly, only shifting into first when under 15 MPH or so then use the parking brake to stop and then get off the road ASAP.

I had to do this about 3 years ago on Thanksgivings night returning home after visiting with my daughter in Charleston, luckily there was very little traffic on the roads, I had a complete brake failure, I had a front caliper steel brake line break because where it attaches to the steering arm the bolt broke and the line was slightly flexing until over time it finally broke, no parts stores were open due to the holiday so I ended up driving all the way home..about 90 miles only using slowing down, downshifting and the parking to come to a stop, it was not all that hard to do and not scary if you know how to use this method but only use it in an emergency, just takes practice and timing, this wasn't a new thing for me because my father taught all of his kids how to do this in a emergency so I have use this method and practiced it many time in my life (I'm old as dirt by the way), it's something I think everyone should know how to do!!

Thanks for the info! That helps. I’m not sure it’s the HVAC since I did have the heat on running, but when I heard the vibration, I turned off the HVAC and it still made the noise when it was off and the car was still running.

I didn’t hear the noise yesterday while driving over the Ravanel Bridge and still didn’t have an issue with brakes at all (but I sure as hell braked way ahead off stop lights and cars just in case). I’ll listen for it again when I’m on I26 today.

Maybe it’s just a noise that happens since my 4Runner is getting older-who knows. If it does persist I may take it to a non-dealerships toyota shop here in town. You can’t ever put a price on safety

And Charleston-without traffic?!?!? Lol. I do love being here when everyone evacuates for storms and then holidays. It’s like the old Charleston that I grew up in. Lived here my whole life and so has my wife and we are both about ready to call it quits and move somewhere less populated. Too many idiots and northerners moving here and changing how Charleston used to be. Sadly it’s not the same Charleston I used to know

 

[AuSeeker]

Thanks for the info! That helps. I’m not sure it’s the HVAC since I did have the heat on running, but when I heard the vibration, I turned off the HVAC and it still made the noise when it was off and the car was still running.

I didn’t hear the noise yesterday while driving over the Ravanel Bridge and still didn’t have an issue with brakes at all (but I sure as hell braked way ahead off stop lights and cars just in case). I’ll listen for it again when I’m on I26 today.

Maybe it’s just a noise that happens since my 4Runner is getting older-who knows. If it does persist I may take it to a non-dealerships toyota shop here in town. You can’t ever put a price on safety

And Charleston-without traffic?!?!? Lol. I do love being here when everyone evacuates for storms and then holidays. It’s like the old Charleston that I grew up in. Lived here my whole life and so has my wife and we are both about ready to call it quits and move somewhere less populated. Too many idiots and northerners moving here and changing how Charleston used to be. Sadly it’s not the same Charleston I used to know

The HVAC actuators will still try and move to the selected position when they're stuck even after you turn off the system, so it still cold be one of the actuators but they usually make more of a clicking/ticking sound when they go bad.

If you have never heard what the brake booster motor sounds like try this so you will know the sound, get in your T4R after it has sat overnight close the door and first turn the ignition to the accessory position so you can make sure the stereo is turned off so it's as quiet as possible, then turn the ignition to the on position but don't crank it, be ready to quickly turn off the HVAC system if it is on so there's no fan noise, once the chime stops you should hear the booster motor running, the sound will be coming from behind the instrument cluster, it should be a slight buzzing/small electric motor sound, it could be a bit more loud if the motor is worn a bit, the motor should only run for around 10 to 15 seconds as it builds up pressure, it's possible if the accumulator is leaking a bit the motor could stop running and then come on again several times until it builds up the pressure(my accumulator needs to be replaced and on mine the motor will come on about 3 to 4 times for less than 10 seconds and runs a little less each time but does stop as the pressure reaches the proper pressure), if you hear no sound when you turn on the ignition to accessory the accumulator could still have pressure in it from when you last drove the vehicle, if this is the case depress the brake pedal 2 to 4 times and the pressure should drop and the motor should kick in, if you never hear the motor it's not working and I'm surprised you haven't noticed the brakes not being right.

If the booster system is working as it should when it was new the motor should only run for around 10 to 15 seconds and then run again after approximately every 3 depressions of the brake pedal, if your booster system work very close to this you don't have any issues with the system and shouldn't worry about the master cylinder/booster system of your brakes.

Yes no traffic in Charleston is a strange sensation...sorta a apocalyptic feeling, but it was around 8PM and most everyone was either still eating turkey or trying to recover from eating, there was still a bit of traffic in the city but i had only a very short 5 minute drive to get over the bridge into West Ashley and from there all the way back to Hilton Head it was almost like a ghost town, and as you probably know once you get passed Ravenel there's really nothing much out on the Savannah Highway until you get to the Beaufort area and then it was even later so still not much if any traffic, so I didn't have to deal with idiots slamming on the brakes for little to no reason and the drive was uneventful and I fixed the brake line the next day.

 

[SC_4RunnerSC]

The HVAC actuators will still try and move to the selected position when they're stuck even after you turn off the system, so it still cold be one of the actuators but they usually make more of a clicking/ticking sound when they go bad.

If you have never heard what the brake booster motor sounds like try this so you will know the sound, get in your T4R after it has sat overnight close the door and first turn the ignition to the accessory position so you can make sure the stereo is turned off so it's as quiet as possible, then turn the ignition to the on position but don't crank it, be ready to quickly turn off the HVAC system if it is on so there's no fan noise, once the chime stops you should hear the booster motor running, the sound will be coming from behind the instrument cluster, it should be a slight buzzing/small electric motor sound, it could be a bit more loud if the motor is worn a bit, the motor should only run for around 10 to 15 seconds as it builds up pressure, it's possible if the accumulator is leaking a bit the motor could stop running and then come on again several times until it builds up the pressure(my accumulator needs to be replaced and on mine the motor will come on about 3 to 4 times for less than 10 seconds and runs a little less each time but does stop as the pressure reaches the proper pressure), if you hear no sound when you turn on the ignition to accessory the accumulator could still have pressure in it from when you last drove the vehicle, if this is the case depress the brake pedal 2 to 4 times and the pressure should drop and the motor should kick in, if you never hear the motor it's not working and I'm surprised you haven't noticed the brakes not being right.

If the booster system is working as it should when it was new the motor should only run for around 10 to 15 seconds and then run again after approximately every 3 depressions of the brake pedal, if your booster system work very close to this you don't have any issues with the system and shouldn't worry about the master cylinder/booster system of your brakes.

Yes no traffic in Charleston is a strange sensation...sorta a apocalyptic feeling, but it was around 8PM and most everyone was either still eating turkey or trying to recover from eating, there was still a bit of traffic in the city but i had only a very short 5 minute drive to get over the bridge into West Ashley and from there all the way back to Hilton Head it was almost like a ghost town, and as you probably know once you get passed Ravenel there's really nothing much out on the Savannah Highway until you get to the Beaufort area and then it was even later so still not much if any traffic, so I didn't have to deal with idiots slamming on the brakes for little to no reason and the drive was uneventful and I fixed the brake line the next day.

I heard the booster motor as you said, and it’s working. Was definitely a WAY different vibration/buzzing noise than the booster motor. Stronger and much louder.

So who knows what it is. It gets me from A to B and drove excellent Sunday at highway speeds. But now when I first brake, I’m hearing a quick brake grind-thinking calipers

 

[46runner]

Look up rumble strip in this forum. Does it sound like what you heard?

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