BENDIX BW1837 manual Preventive Maintenance, General, ET-S& ET-S2TREADLE Removal, Disassembly

As the potentiometer rotates, its resistance changes. This way, the potentiometer can react to the driver’s request for engine power through the ET-S™or ET-S2™treadle by changing resistance. The resulting change of voltage is sensed by the electronic engine controller.

The electronic treadle receives its supply voltage from the engine control unit. If the driver does not request engine power, the treadle is in the idle position. This condition is also referred to as “Closed Throttle.” In this state, the potentiometer returns the minimum percentage of supply voltage to the engine control unit (see Figure 2).

As the driver depresses the treadle, the electronic treadle output voltage increases (see Figure 3). The potentiometer allows an increased amount of its supply voltage to return to the engine control unit, which in turn increases the engine’s speed.

In the full, or “Open Throttle” position, the driver has depressed the treadle to its furthest possible point. This is the state of least potentiometer resistance. The electronic treadle returns the maximum percentage of supply voltage to the engine control unit (see Figure 2).

PREVENTIVE MAINTENANCE

Important: Review the warranty policy before performing any intrusive maintenance procedures. An extended warranty may be voided if intrusive maintenance is performed during this period.

Because no two vehicles operate under identical conditions, maintenance intervals will vary. Experience is a valuable guide in determining the best maintenance interval for a vehicle.

GENERAL

Important: Visually check for physical damage to the electronic treadle such as broken or missing parts. Actuate the pedal five times from stop to stop, noting any binding or soft pedal response.

Important Note: DO NOT DISASSEMBLE THE ACTUATOR

BODY. Replace the ET-S™or ET-S2™treadle if there is any binding, soft pedal actuation or if the nylon washers or retaining rings indicated in Figure 4 are cracked or have signs of deterioration.

2

CAM FOLLOWER	RETAINING
DRIVE SHAFT	RINGS
POTENTIOMETER
MOUNTING PLATE
	NYLON
	WASHERS

FIGURE 4 - TOP SECTIONAL VIEW

Perform the inspections presented at the prescribed interval. If the electronic treadle fails to function as described, it should be repaired or replaced with a new or genuine Bendix remanu- factured unit, available at any authorized parts outlet.

Every 3 months, or 25,000 miles, or 900 operating hours:

1.Remove any accumulated contaminants and visually inspect the exterior of the electronic treadle assembly for physical damage or excessive corrosion.

2.Inspect electrical connections and cable assembly for signs of corrosion, wear, or physical damage. Replace as necessary.

3.Inspect treadle spring, sleeve bearing, nylon washer, rubber treadle cover (ET-S™treadle only) and retaining ring for cracks or deterioration. Replace as necessary.

ET-S™& ET-S2™TREADLE REMOVAL

1.Park the vehicle on a level surface and block the wheels.

2.Drain the air pressure from all vehicle reservoirs.

3.Disconnect the cable assembly of the potentiometer. Lift the lock tab and pull the connectors until they disengage.

4.Remove the electronic treadle from the vehicle, set aside the mounting hardware for reassembly.

DISASSEMBLY

Please note that the internal mechanism of the ET-S™and ET-S2™treadle are not field-serviceable and therefore individual parts or parts kits are not available for these components. Disassembly may lead to malfunction of the ET-S™or ET-S2™treadle.

The following instructions cover the maintenance and replacement of the potentiometer and treadle (with its bearing, spring etc.) only. The instructions provided with those items should be followed in lieu of the steps presented here. There are no other field-serviceable parts.