brake problem

[86turbo]

Lately, if I stomp on the brakes or let the car idle for a while, the red "brake" light on the dash will come on, and the power brakes will quit, making the pedal stiff and hard to press. Any ideas? What should I check first?
Dan

[arium]

Have you checked to see how much vacuum your brake booster is getting. Sounds like either a leak or pump problems. At idle your pump is spinning a lot slower than it does with the car at speed. An inefficient pump may not be able to keep up with your vehicles vacuum needs at idle. I believe that there is also a check valve in the booster to prevent vacuum bleed off under these conditions. That allows you to press the pedal once or twice to let you stop the vehicle in the event of a failure. I'd check the pump, hoses and booster.