Brake help?

[JAMES GAGER <TSUNAMIKID@domain.elided>]

Hi, I've been reading this site for a while and it has been interesting.
I'm  not sure I fit in with all the Scouts, Travelalls, ect. but with
all the apparent knowledge out there perhaps someone knows a solution to
my problem.
I have a 1939 IH 1/2 ton D-2 pickup and would like to upgrade the
braking system. I don't want to change the rear axel or the front
running gear ( other than new drums or discs ) unless I absolutely have
to. It probably should have a new master cylinder, ect.  Any help?
Where do I start?
Thanks .. Jim Gager.......