1996 Aerostar Abs Rabs Component Locations

1996 Ford Truck Aerostar AWD V6-245 4.0L

Copyright © 2008, ALLDATA

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Antilock Brakes / Traction Control Systems: Description and Operation

Location View Item 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Part Number 2B120 2078 2261 2267 2268 2262 2282 2C008 2B373 2234 2264 2078 2B121 2263 2140

Description Disc Brake Caliper (RH) Front Brake Hose (RH) Rear Wheel Cylinder Rear Brake Tube (RH) Rear Brake Tube (LH) Rear Wheel Cylinder (LH) Rear Brake Hose RABS Valve Output Tube RABS Valve RABS Valve Input Tube Front Brake Tube Front Brake Hose (LH) Front Disc Brake Caliper (LH) Front Brake Tube (RH) Brake Master Cylinder

16.

2005

Power Brake Booster

PURPOSE The Rear Anti-Lock Brake System II (RABS II) continuously monitors rear wheel rotation during braking and adjusts rear brake hydraulic pressure to prevent full rear wheel lock-up. OPERATION The (RABS II) continually monitors rear wheel speed with a sensor mounted on the rear axle housing (4010) while the brakes are applied. When the teeth on the speed sensor ring, mounted on the ring gear, pass the sensor pole piece, an AC voltage is induced in the sensor circuit with a frequency proportional to the average rear wheel speed. In the event of an impending lockup condition during braking, the RABS II modulates hydraulic pressure to the rear brake drums (1126). This inhibits rear wheel lockup. When the brake pedal (2455) is applied, the anti-lock brake control module (2B373) senses the drop in rear wheel speed. If the rate of deceleration is too great, indicating that wheel lockup is going to occur, the anti-lock brake control module activates the electro-hydraulic valve causing the isolation valve to close. With the isolation valve closed, the rear wheel cylinders (2261) are isolated from the brake master cylinder (2140) and the rear brake pressure cannot increase. If the rate of deceleration is still too great, the anti-lock brake control module will energize the dump solenoid with a series of rapid pulses to bleed off rear wheel cylinder fluid into an accumulator built into the RABS valve. This will reduce the rear wheel cylinder pressure and allow the rear wheels (1007) to spin back up to vehicle speed. Continuing under RABS II module control, the dump and isolation solenoids will be pulsed in a manner that will keep the rear wheels rotating while still maintaining high levels of

1996 Ford Truck Aerostar AWD V6-245 4.0L

Copyright © 2008, ALLDATA

9.90

Page 2

deceleration during braking. At the end of the stop, when the operator releases the brake pedal, the isolation valve de-energizes and any fluid in the accumulator is returned to the rear brake tube (2267) and up to the brake master cylinder. Normal brake operation is resumed. CONSTRUCTION The system consists of a Computer Module (ECU), Rear Anti-Lock Brake System (RABS) Valve, vehicle speed sensor (VSS) (9E731) and rear axle exciter ring.