Gushing, hissing sound from brake pedal

[Vortech347]

This just developed today. Brakes appear to work fine. But put alot of pressure on the pedal or pump them and you hear an air/gushing sound. I know for SURE there is no air in the lines. I will double check tomorrow though. The sound is coming from under the dash.

Any idea's? I'm supposed to take a 900 mile road trip next week in this beast.

[fastblackmerc]

This just developed today. Brakes appear to work fine. But put alot of pressure on the pedal or pump them and you hear an air/gushing sound. I know for SURE there is no air in the lines. I will double check tomorrow though. The sound is coming from under the dash.

Any idea's? I'm supposed to take a 900 mile road trip next week in this beast.

You won't hear it if there is air in the system. I bet it the power brake booster. Maybe it got a hole in the diaphragm. Is the pedal harder to push?

[Vortech347]

Pedal pressure is the same as its always been.

I'll get under the dash tomorrow and see WTF is up. Its annoying.

[Marauderman]

Sounds somewhat similar to my situation awhile back---Turned out my ABS sensors were coming out of their position slot on my rear brakes making those similar sound under my dash .....you may need to pull tires off to check them ---maybe --then maybe not the problem--my .02c

[Vortech347]

Thank you. any idea's on where to start looking will safe me hours! :)

I'll report back.

[LeoVampire]

If the internal seals on the Master cylinder plunger are getting tired it can let fluid by pass it and make that type of sound as well that you will hear inside of the car.

Again without hearing it or doing a real diagnostics I can not tell you for sure just going on experience with other customers cars in the past vs those type's of sounds inside of the car that are brake related.

[Jolly Roger]

Is there a hose going to the cruise control moduale?

[Marauderman]

Thank you. any idea's on where to start looking will safe me hours! :)

I'll report back.

Gee man--I did--an hour before your post here--and now its 8 hours since--hopefully--you have pulled off rear wheels to check the ABS sensors----

[Vortech347]

ABS sensors, intact.

No vacuum or fluid leaks I could find of any kind.

Went out and beat on it pretty good. Brakes are A-ok. Just making an intresting noise they have never made.

[Marauder Rick]

same exact thing happened to me on my '97 thunderbird. Lots of pressure on pedal and an "air leaking" noise when pressed. It was my brake booster. once i replaced it and bled the brakes everything was good as new.

[ntd]

Replace the brake booster see them go bad all the time more common on the Taurus/Sable cars but the sound that your describing is typical of a brake booster going bad. If you were in Detroit I would offer my help

[Vortech347]

Thanks guys.