Power Brakes

I have never encountered this before. Under high vacuum conditions, the power brakes work fine. If I gas it hard and then brake immediately, the power assist is gone until the vacuum comes up a second later. Any ideas?

RE: Power Brakes

[div class="dcquote"][strong]Quote[/strong]
I have never encountered this before. Under high vacuum conditions, the power brakes work fine. If I gas it hard and then brake immediately, the power assist is gone until the vacuum comes up a second later. Any ideas?
[/div]

Shouldn't take that long. I'd suspect a vacuum leak.

RE: Power Brakes

Sounds about normal to me but, I don't drive my car like that.

I'm curious, why would you do that?

RE: Power Brakes

Replace the vacuum check valve in the brake booster. Simple fix.

RE: Power Brakes

I have already replaced the check valve and no change.

RE: Power Brakes

what do you mean by "gas it hard"?

If you're doing a burnout and you pump the brakes a couple of times to creep forward and leave some nice stripes, it'll take a few seconds for brakes to come back.

If you're just running down the dragstrip WOT you should have brakes immediately, at least for the first pump or two.

Could be a booster or the check valve. Probably a vacuum leak somewhere, possibly internal to the booster.