The Hill-Holder, introduced on late model cars, is a device that prevents the car from drifting backwards when starting up an incline from a stop. The Hill-Holder holds the brake on, temporarily, until the clutch pedal is released and the car is in forward motion.
A Pressure Hold Valve (PHV) is connected to one of the service brake lines. A clutch connected cable opens or closes the valve. When the vehicle is stopped and the clutch depressed hydraulic pressure is maintained even when the brake pedal is released.
REMOVAL & INSTALLATION
To remove the Hill-Holder PHV:
- Drain the fluid from the master cylinder primary side.
- Remove the cable adjusting nut, clamp and cable mounting bracket from the engine mounting.
- Detach the PHV cable from the mounting clips.
- Separate the connector bracket from the PHV support.
- Disconnect the brake line from the PHV. Use a flare wrench to prevent damage to the line nut.
- Remove the PHV.
- Installation is the reverse of removal.
- Bleed the brake system after installing the PHV.
- Inspect the clutch pedal free play adjust as necessary.
- Test the Hill-Holder on a grade of 3° or higher.
- If the vehicle moves when the Hill-Holder is applied or the engine stalls when the Hill-Holder is released:
- Engine stalls: The Hill-Holder is releasing after the clutch. Loosen the adjusting nut gradually until smooth starting and no stalling is enabled.
- Vehicle slips backwards: The Hill-Holder is releasing before the clutch. Tighten the adjusting nut so that the Hill-Holder is released after the clutch engages.