Crown Victoria V8-4.6L SOHC VIN 6 (1996)
Parking Brake Release Motor: Testing and Inspection
Vacuum Release Parking Brake
Look closely at the operation of the release linkage as the parking brake pedal is depressed. Then, check the operation of the linkage when the
"PUSH" to release feature is activated. These checks will indicate whether the parking brake linkage is operating properly or requires service or
adjustment. Replacement or service of the system may be necessary if the parking brake is unable to prevent moderate vehicle movement. Perform
tests of the parking brake system and controls after making sure the linkage and manual release feature operate properly.
When testing a parking brake vacuum release system, a minimum of 37 kPa (11 in-Hg) should be available at all points where vacuum is applied.
This can be checked with a gauge, such as Rotunda Vacuum Tester 021-00014 or equivalent.
Failure to maintain 37 kPa (11 in-Hg) during vacuum system tests could be caused by a loose hose connection, resulting in a vacuum leak. When
checking for vacuum between two points, trace the hose along its entire routing to ensure it is not crossed with another hose or connected to the
wrong connection.
All of the vacuum parking brake control checks are to be performed with the engine running at idle speed.
To detect any leaks in the parking brake hoses or to find disconnected or improperly connected hoses, listen for a hissing sound along the hose
routing.
CAUTION: Do not apply air pressure to the vacuum system under any circumstances as damage to the actuator diaphragm in the parking brake
vacuum motor may occur.
1. Start engine and run it at idle speed. With the transmission shift control in neutral, depress parking brake pedal to apply parking brake. Move
transmission shift control to D range while using the service brake to prevent the vehicle from moving. Observe the parking brake sector to see if
the sector returns to its zero travel position when the parking brake releases. If parking brake releases, the parking vacuum control is working
properly.
NOTE: The parking brake vacuum release does not operate with transmission in REVERSE. It only releases in DRIVE.
2. If parking brake does not release, test for vacuum at the vacuum line connected to the parking brake release vacuum motor. This can be
accomplished by removing the hose from vacuum motor component and attaching it to the vacuum gauge.
NOTE: Vacuum will be available at the vacuum motor only when the transmission selector is in the D range. Connect two distributor tester
vacuum hose adapters together with a coupling as a connector attaching the gauge. A minimum of 37 kPa (11 in-Hg)is required to actuate the
parking brake vacuum motor. If a minimum reading is not present check system for leaks.
