Town Car V8-302 5.0L (1987)
Parking Brake Release Motor: Description and Operation
The vacuum power unit will release the parking brake automatically when the transmission selector lever is moved into any driving position with the
engine running. The brakes will not release automatically, however, when the selector lever is in neutral or park position with the engine running, or in
any other position with the engine off. The lower end of the release handle extends out for alternate manual release in the event of vacuum power
failure or for optional manual release at any time. To detect leaks in the vacuum release parking brake lines or to find disconnected or an improperly
connected line, listen for a hissing sound along the line routings. Do not apply compressed air to the vacuum system when conducting a leak test. The
actuator diaphragm in the parking brake vacuum motor may be damaged. Perform the following to detect leaks in the vacuum release system:
1.
Start and operate engine at idle. Position transmission gear shift lever into Neutral and apply parking brake.
2.
Position transmission gear shift lever into Drive and check parking brake sector to insure sector returns to its stop (zero travel position), when the
parking brake releases. The parking brake vacuum release does not operate with the transmission in Reverse.
3.
If parking brake does not release, disconnect vacuum line from parking brake release vacuum motor and connect a suitable vacuum gauge to the
line. A minimum of 10 inches Hg is required to actuate the parking brake vacuum motor. If a minimum reading is not present when checking each
of the above components, they must be replaced.
