Air noise from brakes

[Achilles]

Yesterday morning I started up my '86 and noticed when I put pressure on the brake pedal that I can hear air noise, then it stops, then starts again, then it stops. If I put presure on the brake pedal and release preasure slightly, it stops. Is this the power brake booster leaking? If so, I am assuming this is not normal and needs to be replaced. Anyone else ever have this happen?

 

[grapeknutz]

the booster is going bad! Tip have someone else replace it! It's not fun.

 

[Edmond]

Yes, the booster is going bad. I wouldn't drive the car until you get the booster replaced.

It's not as bad as Grape said. I replaced my booster along with the master cylinder about 3 years ago and it was 4 hours of work. The difficult thing is accessing the 2 nuts at the base of the steering column. But an extension and a universal will take care of that!

The OEM booster is plastic and they run in the $250 area while the metal boosters are aftermarket pieces and run in the $150 neighborhood.

 

[WhalePirot]

It sounds like the booster. Is there any change in brake pedal effort or engine ops, when the hissing occurs?

Can you pump the booster with a handheld vacuum pump and see if it holds pressure (or hisses)? I guess I'd like to know if the hose or the booster is bad before doing the repair.

 

[scorp508]

Yep, that definitely sounds like your booster has gone bad. It isn't exactly hard to replace, just a bit of a pain in the butt as one of the nuts you need to remove on the interior side is hard to get to.

 

[Achilles]

Thanks guys. You just reafirmed what I was afraid the problem might be. Whale, I haven't checked to see if the hose is leaking or if its the booster itself. The idle is affected by the air leak. But I can hear the air only when the brake pedal is pushed down. Pedal feel seems ok. But, then again if this has been ongoing and I never knew it, I don't have anything to compare to. The pedal feels fine. Edmond, I'd like to know how good these aftermarket boosters are. Since this car is mainly used for autocross, I don't want to sacrifice performance for cost. Now I'm thinking that this booster thing is probably what has been causing my braking problems that I had posted earlier in another thread. During the past racing event under hard braking, I had been experiencing momentary wheel lock-up before the ABS kicked in. Could be a related issue.

 

[Edmond]

In my opinion, the aftermarket booster works just as well as the original did. The only parts that I would say stay away from aftermarket are electrical parts. When it comes to electrical parts, go OEM and go new. Do not buy used electrical parts.

 

[Edmond]

Junkie,

Those are an extension of my body. How could you ask me to do that?:L

 

[tyrel]

Replacing the booster is not fun. The only way to do it is remove the drivers seat, lie on your back, and let the expletives fly as you try to remove the nuts.

 

[jsinga]

If you tweak the bracket on the one side the nut is easier to get to.
Shut off the engine and pull on the vacum hose, you can tell if the booster is holding. If not most of what's wrong is the diaphram has a hole in it. Those plastic boosters are held together by the 2 nuts under the studs the master cylinder came off. Be warned there is a BIG spring in there! Once the thing is opened up the diaphram is easy to change, the last one I changed was about $30 delivered.

JS

 

[Edmond]

Buy me a plane ticket from Chicago and I'll come out to change it for you.:L