Brake pressure problem '86 5KTQ

["Hale, Duane A WRAMC-Wash DC" <Duane.Hale@NA.AMEDD.ARMY.MIL>]

Odd happenigs in the brakes department:

Replaced the bomb (twice!), but the "brake" triangle light still flashes for
the first two minutes or so after start up, then goes away.  There's plenty
of Pentosin and brake fluid in the reservoirs.  Plus, the brakes feel
'un-assisted' for the first mile or so, then all of the sudden - they will
work fine (Also, the car will pull slightly to the left upon braking under
'non-assist' mode, then when the brakes suddenly return to normal, the car
straightens out).  Bad master cylinder?

Duane