Brakes Hissing when I hit the brakes

[AbhorrentSpecies]

So I just noticed this today. Started out only minor and sounded like the radio was on with no music. Now it's very loud and you can clearly hear it when brakes are pressed. Is this for sure a brake booster issue? Or could it just be a vacuum leak? Any info on diagnosing and replacement of parts would be greatly appreciated. Also, is this super dangerous? Should I retire the car until it's fixed?

 

[General karthief]

Pull the vacuum line off the booster and plug it, push on the brake peddle, it will be super hard so don't try to drive around, see if it makes the sound or is different.

 

[AbhorrentSpecies]

Pull the vacuum line off the booster and plug it, push on the brake peddle, it will be super hard so don't try to drive around, see if it makes the sound or is different.

Okay. I'll try that in a bit.

 

[AbhorrentSpecies]

Pull the vacuum line off the booster and plug it, push on the brake peddle, it will be super hard so don't try to drive around, see if it makes the sound or is different.

The sound stopped completely. And it definitely sounds like it's coming from inside the car.

 

[General karthief]

Unplug the vacuum hose to the vacuum tree,
Who am I kidding, change the booster, the diaphragm is leaking in the back and the sound is coming into the cabin through the opening in the firewall where the rod goes through.
JMO

 

[Mustang5L5]

Booster vac leak.

 

[AbhorrentSpecies]

Unplug the vacuum hose to the vacuum tree,
Who am I kidding, change the booster, the diaphragm is leaking in the back and the sound is coming into the cabin through the opening in the firewall where the rod goes through.
JMO

This was pretty much what I figured. So I can't change it until sometime next week. Probably friday when the part comes in. How dangerous is it to drive until then?

 

[AbhorrentSpecies]

Booster vac leak.

Heard, thank you!

 

[Mustang5L5]

This was pretty much what I figured. So I can't change it until sometime next week. Probably friday when the part comes in. How dangerous is it to drive until then?

could leak at a small rate, or fail totally and you have no assist. Really it’s a drive at your own risk type of situation

 

[AbhorrentSpecies]

could leak at a small rate, or fail totally and you have no assist. Really it’s a drive at your own risk type of situation

Okay, so if it fails totally. Would I still have brakes? Would it just be really hard to stop? Cause I kind of need to get to work lol

 

[Mustang5L5]

You’ll have brakes but you’ll be standing hard on that pedal.

take the vac line off the booster and plug it, and then drive up your street and back slowly and you’ll get a sense of what it will be like.

 

[AbhorrentSpecies]

You’ll have brakes but you’ll be standing hard on that pedal.

take the vac line off the booster and plug it, and then drive up your street and back slowly and you’ll get a sense of what it will be like.

Yeah, I already took it off and plugged and the pedal was hard as . Didn't go driving though. I'll take it for a spin and see how it feels that way I know what I'm in for if it fails in the next week. I could just run a hose into the car and suck on it whenever I hit the brakes lol I know a girl that would be good at it.

 

[AbhorrentSpecies]

I have one other quick question. Is it possible to remove the booster without unhooking the brake lines from the MC? Like just remove the MC from the booster and the bolts inside the car and pull the booster out?

 

[Mustang5L5]

Yes. Unbolt the MC and carefully pry it forward just enough to clear the booster studs and pushrod. It can be removed then.

unbolting the upper intake and moving it over can give you a little extra room

 

[General karthief]

I just changed my booster without unhooking the brake lines but the top of my engine is off so I couldn't tell ya,

 

[AbhorrentSpecies]

I just changed my booster without unhooking the brake lines but the top of my engine is off so I couldn't tell ya,

Well I have a small leak from my vacuum tree, I think, so I'll be removing my intake anyway. I also have a bit of oil leaking from my valve covers. Think I may have over tightened them. So I'll be going in to readjust all that stuff. I'll do the brake booster while I'm at it. Hopefully that will make it easier to get to.