Ford Mustang/Capri 1979-1988 Repair Guide

Self-Adjusting Clutch


The self-adjusting clutch control mechanism is automatically adjusted during normal operation by a device on the clutch pedal. The system consists of a spring-loaded gear quadrant, a spring-loaded pawl, and a clutch cable which is spring-loaded to preload the clutch release lever bearing to compensate for movement of the release lever, as the clutch disc wears. The spring-loaded pawl, located at the top of the clutch pedal, engages the gear quadrant when the clutch pedal is depressed, and pulls the cable through its continuously adjusted stroke. Clutch cable adjustments are not required because of this feature.


The self-adjusting feature should be checked every 5,000 miles. This is accomplished by insuring that the clutch pedal travels to the top of its upward position. Grasp the clutch pedal with your hand or put your foot under the clutch pedal, pull up on the pedal until it stops. Very little effort is required (about 10 lbs.) During the application of upward pressure, a click may be heard, which means an adjustment was necessary and has been accomplished.


The starter/clutch switch is designed to prevent starting the engine unless the clutch pedal is fully depressed. The switch is connected between the ignition switch and the starter motor relay coil and maintains an open circuit with the clutch pedal up (clutch engaged).

The switch is designed to self-adjust automatically the first time the clutch pedal is pressed to the floor. The self-adjuster consists of a two-piece clip snapped together over a serrated rod. When the plunger or rod is extended, the clip bottoms out on the switch body and allows the rod to ratchet over the serrations to a position determined by the clutch pedal travel limit. In this way, the switch is set to close the starter circuit when the clutch is pressed all the way to the floor (clutch disengaged).

Testing Continuity

See Figure 1

  1. Disconnect in-line wiring connector at jumper harness.
  3. Using a test lamp or continuity tester, check that switch is open with clutch pedal up (clutch engaged), and closed at approximately 1 in. (25.4mm) from the clutch pedal full down position (clutch disengaged).
  5. If switch does not operate, check to see if the self-adjusting clip is out of position on the rod. It should be near the end of the rod.
  7. If the self-adjusting clip is out of position, remove and reposition the clip to about 1 in. (25.4mm) from the end of the rod.
  9. Reset the switch by pressing the clutch pedal to the floor.
  11. Repeat Step 2. If the switch is damaged, replace it.

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Fig. Fig. 1: Starter/clutch interlock switch self-adjuster clip installation