Just want to know before I spend the big bucks. This is what happened. 1st my vsc/brake lights come on. Then a loud buzzing sound. Finally, I after all that, my brakes stiffen up. I took it to a shop and they bled it the regular way. The mechanic hears a sound from the bmc. Its like a motor. He then taps bottom of bmc and the sound comes back and all my the sudden car is back to normal. After a few more stops, lights n sound comes back. I tap bmc sound comes back for a sec then acts normal. What can that be? Is there a seperate motor to the bmc? Thanks in advance.

 

1. SEARCH Theres is TONS regarding BMC, unless you have new insight to contribute.
2. Your mechanic didnt bother reading the Codes? Did he clear them? Does he use Pixie dust and Magic beans?
3. From all the Info you have posted and without you Searching,m im gonna say yes is Fubarbed

 

There were tons of codes like c1256 kept on coming up. Ive did a search. it's just kind of weird for the mechanic to hit the bmc like a bad starter and it would work. hence the reason why i'm asking if it would be the bmc or booster or something else. just in case someone else has had this issue.

 

Not weird at all. But i think you've answered your own question whether or not its faulty.

 

What year is your GS? Is this the original booster/master?

 

I had the motor rebuilt for my master ....it saved me lots of money

I was talking to another member who explained the brake boosters have a small electric motor that drives the pump/controls the nitrogen cell, on the 98-00 units the brushes in the electric motor where kinda too stiff and wore the units out much faster than the newer 01+ year boosters
If your able....try pulling your booster and then take off the motor from the assembly..
It is 12v and you can test it on your battery, most likely you have a dead zone in the motor and sometimes you can turn it by hand and find a good spot/contact point .....and Your welcome to Pm me with more questions

 

Hi can you give a little more info on how to get the booster off really dont wont to spend all that money for a new one.

 

what is the cause for feedback when im braking and the buzzing noise....is that just regular abs kicking in or a problem....i plan on changing pads and rotors soon. but for now that sound and bit of feedback has me curious and quite irritated?

also what are the signs of a brake booster problem?

 

you can't just take out the booster alone. the unit is all in one piece. You would need to replace the entire thing, which includes master cylinder as well as the booster.

you can find 2001+ BMC on Ebay for around $500-700. Easy install

 

The buzzing from the BMC is normal. It should only buzz one or two times every time you drive. If more than often, then your BMC could be faulty. Happened to my original BMC. It buzz more than often. Turned out it had internal leak.

 

It buzzes so that it can build pressure and keep it stored in the small can (accumulator).

 

Is there any way to get rid of the buzz? My car did not make any buzz noise until about 90k miles. This is a 2003 GS430 which had regular brake fluid/ pad/rotor maintenance done since it was new. Would replacing the BMC the only solution tos this issue?