Master Cylinder & Power Brake Unit Assembly Test
WARNING: This page is about a different car, the 1994 Eagle Vision, 1994 Dodge Intrepid, 1994 Chrysler New Yorker, 1994 Chrysler LHS, and 1994 Chrysler Concorde. However, it is still accessible from the selected car via links, so may be relevant.
- Start engine. Ensure there are no power brake unit vacuum hose leaks. Stop engine. Shift transmission to Neutral. Pump brake pedal until all vacuum reserve in power brake unit is depleted. Lightly press and hold brake pedal.
- If pedal does not hold firm (falls away), replace master cylinder. If pedal holds firm, start engine. If pedal falls away slightly under light foot pressure, then holds firm, go to next step. If no change in pedal occurs, replace check valve, and retest. If no change in pedal occurs, replace power brake unit.
- Release brake pedal. Start engine and operate at 1500 RPM. Release accelerator, and immediately turn off engine. This rebuilds power brake unit vacuum reserve.
- Wait at least 90 seconds. Press brake pedal. If power brake unit does not assist pedal application at least twice, test power brake unit and check valve. Refer to the POWER BRAKE UNIT TEST and the CHECK VALVE TEST .