Hi all! The past few days when i press and release the brakes it makes a "zoom/vroom" like noise from inside. I had the same problem with my old car(merc. cougar) we replaced the booster on the cougar and nothing happened so i am thinking it could be the master cylinder. which one could it be..i dont want to go buy one part and put it in and it be the other.

 

Had a 92 Bonneville that had the master go, pretty much the same car mechanically.

 

get under the hood and depress the brake pedal and see if that is the source of the sound.
if you hear that sound from under the dash, the seal in the booster has failed.

master cylinders dont make noises .. that i know off ...

 

the noise is coming from under the dash. so it is the booster[:@]

 

correction



i actually meant to say : .... get under the dash and ............."

get under the hood and depress the brake pedal and see if that is the source of the sound.

 

Thats where its coming from i am going to get the part today and it will be done tomorrow. Hopefully it works. Thanks guys

 

upon R&R, pay attention to your brake pedal & stop light switch assy.
its the biggest pain if you forget what goes where.

also, check and see if your master cyl is leaking - if it is, replace it.


lol

 

i will have the mechanic check the master cylinder... i dont trust doing this myself. I'm glad my wife's family as a friend who is a good mechanic(actual mechanic owns his own business..wouldnt trust a guy who says he is one then screws it up more..had it happen)..he lets us buy the parts and he does the work for half than what others want. i will let you know when i get the car back. thank you

 

that is a good thing .. there is nothing like having good brakes and tires .. saves your skin.

when i commented on the master cylinder, it was in regards to the master cyl back seal that can ruin a booster if it leaks brake fluid onto the booster seals.

one last piece of advice? flush the entire brake system. it is a good bet that your fluid is original OEM fluid, 15+ years old. do it by bleeding at each wheel until you get fresh fluid. I usually flush / bleed the system when I replace components such as brake pads and certainly a master cylinder or booster. you be smart to ignore the advice of those that say brake fluids never need changing as DOT-3 fluid absorbs water/moisture and will GEL given the right cir***stances and time. GEL fluid can bring on catastrophic failure of several components .. big $$$ !