This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
Mushy / spongy brakes, especially after brake servicing: Have the brake
fluid bled *properly* (most mechanics will not do it the correct way). Jim
Murphy says that Chrysler has a new procedure involving pumping the brakes
to pressurize the system, then opening the bleed screw to allow the fluid
and air to rush out. The details:
1: Pump pedal three or four times and hold it down before bleeder
screw is opened
2: Push pedal toward floor and hold it while bleeder screw is opened
3: Release the pedal after the bleeder screw is closed
4: Repeat steps 1 through 3, four or five times, at each bleeder screw to
pass a sufficient amount of fluid to expel all the trapped air from
anywhere in the system. CAUTION: Just cracking the bleeder screw often
restricts fluid flow, and a slow weak fluid discharge will NOT get all the
air out. Open the screw at least one full turn.