Modulator Function Inspection

This inspection determines whether the basic brake system continues to operate normally when the modulator unit fluid pressure is low.

Fig. 11 Modulator Function Check:

1. Remove bleeder cap from maintenance bleeder on modulator unit, then attach wrench to maintenance bleeder, Fig. 11.
2. Connect suitable rubber tube to maintenance bleeder, then set other end of rubber tube in suitable container. Do not loosen maintenance bleeder too much. High-pressure brake fluid can burst out.
3. After fluid stops flowing out, loosen maintenance bleeder more to completely release pressure.
4. Torque maintenance bleeder to 8 ft. lbs.
5. Raise and support vehicle, then have an assistant depress brake pedal firmly. Wheels should not rotate.
6. Remove cap and fill reservoir to MAX level with fresh brake fluid. Pour brake fluid slowly so it does not foam, then wait for a few minutes.
7. Start engine and let idle for a minute, then stop engine.
8. Check brake fluid level in reservoir. It should be below MAX level line. Refill reservoir with fresh brake fluid to MAX level line again.
9. After inspection, start engine and make sure ABS indicator light goes off.