[V8] Is it the bomb?

[Gunter Lorberg]

Last week the brake pedal in one of my V8's began doing something odd.  I would get in the car to start up the engine.  Just prior to starting it I'd step on the brake pedal but it felt unually firm and lead-like.  Starting the engine made no difference, at least to begin with .  I really noticed that something was amiss when putting the car in reverse and backing the car out of the garage.....again, all within 10-15 seconds of starting the engine.  Once in the driveway, I'd step on the brake but it took excessive force to halt the car....like there was no brake assist hydraulic pressure.  The latter, however, would seemingly be restored after the engine had been idling for 15-20 seconds.  After that, the brakes funcitoned as they normally do....no perceptible change.  I immediately thought that it was likely the bomb.  However, the dashboard brake light was not lighting up to signal a problem (lights up otherwisewhen using the handbrake or briefly when
 turning on the ignition ).  I had to replace the bomb about 3 1/2 years ago.....at that time (prior to replacement) the brake light came on and stayed on for 20-30 seconds upon start-up before it turned off......since then I've driven about 80 000 miles........car has about 220 000 miles......

I think the bomb is going again but could this be something else, especially given that the bomb warning light is not signaling to me that something's wrong?  Anyone have any ideas?

Gunter
(2) 1990 Canadian V8's with automatics