If I can live with the hissing does the brake booster need to be changed. The car brakes just fine. I was told by a mechanic the booster just lifts up the brake pedal and has nothing to do with braking; is this true?

Thanks

 

The vacuum leak can cause a check engine light if it gets bad enough. Also, if it gets bad enough, you can lose vacuum assist, which would give a hard pedal (as of braking with the car off)

 

Thanks for the reply.Would I ever lose braking ability or it would just give a hard pedal? I am eventually going to get it fixed i just want to know if it has to be done immediately.

 

You wouldn't lose braking, just brake assist. The booster uses vacuum to multiply the force of your foot. So it would be hard to brake if all assist is lost.

Also, don't go to that mechanic anymore.

 

Thanks again and I already stopped going to him; I never felt trust with him.

 

I noticed most people state hissing occurs when they push on brake but mine happens after I push the peddle down and its rising. Does that still sound like a bad booster or could it be the check valve in the hose instead. Also, the pedal is not difficult to press. Thanks in advance for replies.

 

I'd have to hear it, but probably the booster. If you hear it in the car, it's the booster