Leaking Brake Booster? Need help!
 

(VIDEO LINK) BRAKE BOOSTER HISSING

Hello, I just recently hear some hissing noises when I hit the brakes on my fd, the noise is coming from inside the car right next to the brake pedal.
Its a lot harder to stop now and the brake gets super stiff, i imagine its the brake booster finally giving up? is there a way to fix the brake booster, taking it apart, replacing lines etc? super new to this!
I have a bridgeport idling around 1450~1550. but once the brakes are pressed it goes up to 1800-2000 while idling

if it is the brake booster, are there any replacements I can get new? or is it only available to buy used ones? my fd is RHD btw

Thank you again!

It sounds like you're experiencing the low vacuum characteristic that high overlap engines are known to produce. This is because the intake and exhaust ports are open at the same time. Less vacuum produced by the engine equates to less braking assist, which is consistent with what you are describing.

The hissing you refer to is likely a vacuum leak somewhere in the system. Replacing the booster is not likely to fix it (unless you have a leaking diaphragm). I believe sakebomb offers a solution that functions as a means to increase vacuum that you might consider.

Hopefully some other folks will chime in...

The hissing sound when I do press the brakes is only audible inside the car, I had my friend try to hear any from the engine bay, and theres no sound. can it be the booster making that noise right behind the firewall from the inside?
Also are u able to hear the hissing noise from the video? Im hoping it works, i uploaded to my google drive

Thank you again!

Must have missed that. I'd bet you have a failing (or failed) booster diaphragm. Perhaps you could confirm by removing the vacuum line connecting it and repeating what you did in the video? If no noise is present after that, I'd think that is what it is.

Not sure who repairs boosters on these cars, but if it ends up being the case, it should be a rather straightforward fix.

Does the booster show signs of fluid running down the front stripping the paint, you might have internal corrosion causing your issue?

FD boosters don't look serviceable the way old time ones were, a brake specialist would be the ones to ask though. You'd probably be better off to just buy a second-hand one however, as it's pretty rare for them to fail. The booster did change a little in outside dimensions in later cars too, but they should all fit.

Hey!
No leaks at all, the reservoir is full and shows no sign of losing fluid
mm.. yea i heard the boosters RARELY fails, but im not sure what it could be then if its not the booster.
kinda dont want to buy one and the problem still persists, i will have to check some out, i also heard chasebays makes a booster delete?
is that okay for driving? i heard its a super different feel on the brakes as well once that is installed

Per your query regarding the chase bays master cylinder/booster delete: https://www.rx7club.com/suspension-w...inder-1162516/

It could be made to work but it will be a little more involved on the mathematical and design side.

https://cimg9.ibsrv.net/gimg/www.rx7...fe8c9b3829.png