Brake Booster Whine

[2002TLCyes]

I have a 2002 land cruiser, and the brakes work great on it. But I do hear a very faint but still noticeable sound that sounds like a pump working for several seconds. I hear it come on after I've used the brakes for more than just a light tap. I guess maybe it's re-building up the pressure or something?

I just have never heard this on any vehicle I've driven and want to know if hearing that on the land cruiser is a bad sign, or normal.

It's not a whine even, and not loud at all. But audible enough for me to notice it.

 

[chrisbruck]

Mine's been doing same thing for the past 5 years. It's the booster pump building pressure up in the braking system. Pretty sure the sound is normal and not a failure sign. It's mounted right there at the master cylinder so the sound is in front of you while driving.

 

[2002TLCyes]

Ah that's a relief.

I've heard of some preventative maintenance on the brake system. What would that be? I asked my mechanic and he said since it's a closed system, as long as it isn't leaking, the fluid doesn't need to be changed. Can anyone confirm or deny?

He said the same thing when I asked him if I need to change the differential/transfer case oils. Ssso the guy really isn't a preventative maintenance person. But I'm curious as to the science behind how gear oils and brake fluids might degrade over time to kill the booster pump/master cylinder whereas timely fluid changes would prohibit that.

 

[2001LC]

It's just the electric booster pump motor filling the accumulator, very normal.

Make sure you read what is printed on top of the brake reservoir. It tells how to check fluid level.

This out of adjustment will give loud and unusually sound.

 

[PinoyLC]

I have a 2002 land cruiser, and the brakes work great on it. But I do hear a very faint but still noticeable sound that sounds like a pump working for several seconds. I hear it come on after I've used the brakes for more than just a light tap. I guess maybe it's re-building up the pressure or something?

I just have never heard this on any vehicle I've driven and want to know if hearing that on the land cruiser is a bad sign, or normal.

It's not a whine even, and not loud at all. But audible enough for me to notice it.

I have the same issue on my 1999 LC when the brake light/buzzing came and completely lost my brakes. I installed a brand new OEM booster and also have that pumping sound. Have you corrected it yet? if not, have you had any issues so far?

 

[2001LC]

The booster pump comes on, pretty much anytime your foot hits the brake peddle. It and the pump makes sounds as any pump and motor will when it's on. If the accumulator bracket (cage) is out of adjustment, wherein one bumper of cage touches accumulator in will make unusual sound as motor runs.

There is a little piece (coupler) that goes between booster motor and pump, that must be seated properly during assemble if motor is separated from pump. I suppose there is a remote chance if not properly seated, motor may turn pump and make unusual sound. But this is highly unlikely.
Here you two couplers (one on lying on white towel one in motor), only one is actually used between motor and pump.

On reservoir print is embossed that tells how to properly fill (Before Adding Brake Fluid) the reservoir by pump peddle 40 times IG (key) off. Once topped to max turn on IG and time how long you hear booster run. Spec (as you can see in FSM) is 30 to 40 seconds.

 

[PinoyLC]

Thank you for the extra time to show me with pictures and guidance. REALLY, REALLY APRECIATE IT... you should run for office