Ejector Supplement for the AD55 Underground Articulated Truck{7000} Caterpillar

Underground Articulated Truck:

AD55 (S/N: ANW1-UP; DNW1-UP)

Introduction

Illustration 1	g01051135

The supplemental product support literature should be used with the appropriate Service Manual and the appropriate Parts Manual that is available for each standard machine. This supplement is used to determine the difference between the custom modifications and a standard machine.

The Service Manual and the Parts Manual that is available for the standard machine should be used if the service information is not in this supplementary product support literature.

Operation and Maintenance

Safety Section

Safety Signs and Labels

There are several specific safety signs on this machine. The exact location of the hazards and the description of the hazards are reviewed in this section. Please become familiarized with all safety signs.

Make sure that all of the safety signs are legible. Clean the safety signs or replace the safety signs if you cannot read the words. Clean the safety signs or replace the safety signs if the illustrations are not legible. When you clean the safety signs, use a cloth, water and soap. Do not use solvent, gasoline, or other harsh chemicals to clean the safety signs. Solvent, gasoline, or harsh chemicals could loosen the adhesive that secures the safety sign. Loose adhesive will cause the safety sign to fall off the machine.

Replace any safety sign that is damaged, or missing. If a safety sign is attached to a part that is replaced, install a safety sign on the replacement part. Any AVSpare dealer can provide new safety signs.

Tailgate

Illustration 2	g01245507

This warning label is located on both sides of the ejector body tailgate.

Illustration 3	g00937680

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No clearance for person in this area when tailgate lowers. Severe injury or death from crushing could occur. Install tailgate safety pin before servicing machine in tailgate area. Remove safety pin and secure before resuming operation.

Operation

Only operate the machine while you are in a seat. The seat belt must be fastened while you operate the machine. Only operate the controls while the engine is running.

Before you move the machine, you must make sure that no one will be endangered.

While you operate the machine slowly in an open area, check for proper operation of all controls and all protective devices.

Do not allow riders on the machine unless the machine has the following equipment:

• Additional seat

• Additional seat belt

• Rollover Protective Structure (ROPS)

Note any needed repairs during machine operation. Report any needed repairs.

Avoid any conditions that can lead to tipping the machine. The machine can tip when you work on hills, on banks and on slopes. Also, the machine can tip when you cross ditches, ridges or other unexpected obstacles.

Avoid operating the machine across the slope. When possible, operate the machine up the slopes and down the slopes.

Maintain control of the machine. Do not load the machine beyond the machine capacity.

Never straddle a wire cable. Never allow other personnel to straddle a wire cable.

Know the maximum dimensions of your machine.

Always keep the Rollover Protective Structure (ROPS) installed during machine operation.

Always anticipate the grade and select the proper gear range for the grade.

For ejector body machines, retract the ejector plate completely before travel. Keep the hoist control in the HOLD position during travel.

When the machine is being loaded, stay in the operator station of the machine.

Obey all road signs.

A signalman should be present, when you move the machine in a building or out of a building.

Product Information Section

Model Views and Specifications

Illustration 4	g01233545
Right side view (1) Hydraulic tank (2) Engine air cleaner (3) Engine (4) Right side fuel tank (5) Final drives (6) Radiator

Illustration 5	g01233546
Left side view (7) Operator station (8) Left side fuel tank (9) Ejector body (10) Battery compartment (11) Steering frame lock (12) Tailgate

Basic machine specifications are listed below.

Table 1

AD55 Underground Articulated Truck with Ejector Body (29.3M3 SAE)
Empty Weight (approximate)	51170 kg (112810 lb)
Loaded Weight (approximate)	102000 kg (224850 lb)
Length (maximum)	11692 mm (460.3 inch)
Width (maximum)	3556 mm (140 inch)
Height (top of empty body)	3602 mm (141.8 inch)

Operation Section

Monitoring System and Operator Station Features

Indicators

Illustration 6	g00938103

Tailgate Down (1) - This indicator will be on when the tailgate is not completely raised. When the indicator is on, the transmission will be limited to a programmed gear limit.

This indicator will also be on if the tailgate position switch is out of calibration. Move the machine to a convenient place to park the machine and stop the engine. Find the cause immediately.

This indicator will be on for three seconds during powerup in order to permit the operator to know that the indicator is functioning properly. It is important for the operator to visually inspect this indicator. If the indicator does not come on during powerup, or if the indicator glows dimly during powerup, or if the indicator remains on and the tailgate is completely raised, find the cause immediately.

Machine Control and Operation

Changing Direction and Speed

Limiting Tailgate Down Gear

This function limits the gear of the machine while the ejector tailgate is down. The gear is limited until the tailgate control switch indicates to the transmission electronic control that the tailgate is up. The transmission electronic control prevents upshifting to any gear higher than the stored value. The value of the gear limit is programmable by the service personnel. Use the Electronic Technician (ET) service tool. The allowed range for this gear limit is first gear to third gear. The value of the factory setting for the gear limit is first gear.

Hoist Control

Illustration 7	g00938105
(1) RETRACT position (2) HOLD positions (3) EJECT position

RETRACT Position (1) - Hold the hoist control lever completely forward in order to retract the ejector body. When the hoist control lever is released, the hoist control lever will return to the HOLD position (2) .

HOLD Positions (2) - When the hoist control lever is in one of the two HOLD positions (2), the ejector plate will not move. The hoist control lever will stay in this position until the hoist control lever is manually moved.

EJECT Position (3) - Hold the hoist control lever completely backward in order to eject the ejector plate and empty the load. When the hoist control lever is released, the hoist control lever will return to HOLD position (2) .

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NOTICE
Do not use the hoist control when the tailgate safety pin is installed. Damage to the ejector body may occur.

Tailgate Safety Pin

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The tailgate may move suddenly and without warning, resulting in personal injury or death. When it is necessary to work under the tailgate with the tailgate raised, install the tailgate retaining pins through the pin bores in the tailgate and body.

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Illustration 8	g01245509

1. Pull rod (1) and remove tailgate safety pin (2) from the stored position.

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Illustration 9	g01245513

2. Ensure the ejector plate is in the fully retracted position and the tailgate is fully raised.

3. Place tailgate safety pin (2) in position as shown.

Note: The following steps are for the removal of the tailgate safety pin.

4. Remove tailgate safety pin (2) .

5. Pull rod (1) and replace tailgate safety pin (2) in the stored position. Release rod (1) to hold the tailgate safety pin in the stored position.

Operating Techniques

Dumping

Ejecting

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Illustration 10	g00938105
(1) RETRACT position (2) HOLD positions (3) EJECT position

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NOTICE
When ejecting, ensure the tailgate is fully lowered before the ejector plate starts moving. If the ejector plate starts moving before the tailgate is fully lowered, contact your local AVSpare dealer.

1. Check that the area around the machine is clear of personnel and of any obstructions before you eject the load. If a signalman is present, follow the signalman's directions.

2. Position the machine straight before ejecting the load. Ensure that all wheels are in contact with firm ground.

3. Move the parking brake control to the ENGAGED position. Move the transmission control to the NEUTRAL position.

4. Pull the hoist control backward to the EJECT position (3) in order to eject the load. Check that the tailgate is in the fully lowered position and the ejector plate is emptying the body. Hold the hoist control in the EJECT position until the desired load has been discharged. Release the hoist control. The hoist control will return to the HOLD position (2) .

5. Before moving the hoist control to the RETRACT position, move the machine away from the dumped load. Push the hoist control forward to the RETRACT position (1) in order to retract the ejector plate. Ensure that the ejector plate is fully retracted and the tailgate is in the fully raised position.

Note: Gears will be limited to a programmed gear limit if the tailgate is not in the fully raised position.

Maintenance Interval Schedule

Note: All safety information, warnings and instructions must be read and understood before you perform any operation or any maintenance procedure.

Before each consecutive interval is performed, all of the maintenance requirements from the previous intervals must be performed.

Table 2

Every 10 Service Hours or Daily
Hydraulic System Oil Level - Check
Ejector Cylinder Bearings - Lubricate
Tailgate and Tailgate Bearings - Lubricate
Every 250 Service Hours or Monthly
Frame and Body - Inspect

Hydraulic System Oil Level - Check

Illustration 11	g01233538

Illustration 12	g01010814
(4) "ADD COLD" mark

The hydraulic oil tank is located on the right side of the machine.

Check the hydraulic oil level with the machine on a level surface and the parking brake engaged.

1. When the ejector plate is fully retracted and the tailgate is fully raised, maintain the hydraulic oil level above the "ADD COLD" mark in upper sight gauge (2). When the ejector plate is fully extended, maintain the hydraulic oil level above the "ADD COLD" mark in lower sight gauge (1) .

2. Remove hydraulic tank filler cap (3) and add oil, if necessary.

3. Clean the hydraulic tank filler cap and install the hydraulic tank filler cap.

Ejector Cylinder Bearings - Lubricate

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NOTICE
Check that the lines attached to all remote grease fittings are undamaged. If the lines are split, grease will not reach the bearings or pins. Machine damage will result.

Wipe all fittings clean before lubricating.

Illustration 13	g00944888

1. Lubricate the left ejector cylinder bearing in the rod end of the ejector cylinder through remote mounted fitting (1) .

2. Lubricate the right ejector cylinder bearing in the rod end of the ejector cylinder through remote mounted fitting (2) .

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Illustration 14	g00945219

3. Move the ejector plate to the fully ejected position. Lubricate the ejector body cylinder bearings in the head end of the ejector cylinder through two fittings (3) (one on each side of the machine).

Tailgate and Tailgate Cylinder Bearings - Lubricate

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NOTICE
Check that the lines attached to all remote grease fittings are undamaged. If the lines are split, grease will not reach the bearings or pins. Machine damage will result.

Wipe all fittings clean before lubricating.

Illustration 15	g00945233
Typical location

1. Lubricate the tailgate pivot and cylinder bearings through three remote mounted fittings (1) on each side of the machine.

Frame and Body - Inspect

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The tailgate may move suddenly and without warning, resulting in personal injury or death. When it is necessary to work under the tailgate with the tailgate raised, install the tailgate retaining pins through the pin bores in the tailgate and body.

Illustration 16	g01245522

1. Ensure the ejector plate is in the fully retracted position and the tailgate is fully raised. Install the tailgate safety pin.

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Illustration 17	g01245525

2. Clean the ejector body with a wire brush or a scraper. Inspect the ejector body. If the body is damaged or worn, repair the body. If you find cracks, contact your AVSpare dealer for specific repair procedures.

3. Remove the tailgate safety pin. If the pin cannot be removed, raise the tailgate to release the tension. After lowering the tailgate, place the pin in the stored position in the body.

Specifications

Hydraulic System

Control Valve (Hoist)

Illustration 18	g00975783

Note: With the ejector body installed, the low pressure relief valve is replaced with a high pressure relief valve. Both relief valves are now the same.

(1) Pressure relief valve setting ... 16550 ± 345 kPa (2400 ± 50 psi)

(2) 2J-6089 Spring

Length under test force ... 36.25 mm (1.427 inch)

Test force ... 278 ± 14 N (62 ± 3 lb)

Free length after test ... 44.12 ± 0.50 mm (1.737 ± 0.020 inch)

Outside diameter ... 12.50 mm (0.492 inch)

(3) Torque for the nut ... 60 ± 10 N·m (44 ± 7 lb ft)

Ejector Cylinder

Illustration 19	g00945236

(1) Apply 155-0695 Thread Lock Compound (High Strength) to the bolt threads prior to assembly. Torque for the 12 bolts ... 115 ± 7 N·m (85.0 ± 5.0 lb ft)

(2) Bore of a new outer cylinder ... 184.15 + 0.1 - 0.0 mm (7.250 + 0.004 - 0.000 inch)

(3) Diameter of a new first stage cylinder ... 171.45 + 0.00 - 0.10 mm (6.750 + 0.000 - 0.004 inch)

(4) Bore of a new first stage cylinder ... 152.4 + 0.1 - 0.0 mm (6.00 + 0.004 - 0.000 inch)

(5) Diameter of a new second stage cylinder ... 139.71 + 0.0 - 0.1 mm (5.500 +0.000 - 0.004 inch)

(6) Bore of a new second stage cylinder ... 127.0 + 0.1 - 0.0 mm (5.00 + 0.004 - 0.000 inch)

(7) Diameter of a new third stage cylinder ... 114.3 + 0.00 - 0.10 mm (4.50 -0.000 + 0.004 inch)

(8) Bore of a new third stage cylinder ... 101.6 + 0.1 - 0.0 mm (4.00 + 0.004 - 0.000 inch)

(9) Diameter of a new fourth stage cylinder ... 88.9 + 0.0 - 0.1 mm (3.50 + 0.000 - 0.004 inch)

(10) Bore of a new outer stage bush ... 171.63 ± 0.05 mm (6.757 ± 0.002 inch)

(11) Bore of a new first stage bush ... 139.80 ± 0.05 mm (5.504 ± 0.002 inch)

(12) Bore of a new second stage bush ... 114.40 ± 0.05 mm (4.504 ± 0.002 inch)

(13) Bore of a new third stage bush ... 89.00 ± 0.05 mm (3.504 ± 0.002 inch)

(14) Apply 4C-9507 Retaining Compound to the threads prior to assembly. Torque for the tube end ... 1900 N·m (1400 lb ft)

Note: Tighten bolts (1) with the cylinder fully retracted.

Note: Lubricate the sealing lips lightly with the lubricant being sealed.

Note: Apply 5P-3931 Anti-Seize Compound (High Temperature) to the pins that hold the cylinders to the ejector body and the ejector plate prior to assembly.

Tailgate Cylinder

Illustration 20	g00945247

(1) Torque for the two check valves ... 48 ± 3 N·m (36 ± 2 lb ft)

(2) Torque for the two relief valves ... 48 ± 3 N·m (36 ± 2 lb ft)

(3) Torque for the four bolts ... 90 ± 5 N·m (67 ± 4 lb ft)

(4) Torque for the nut ... 460 ± 14 N·m (340 ± 10 lb ft)

(5) Bore of a new cylinder ... 88.9 + 0.1 - 0.0 mm (3.50 + 0.004 - 0.000 inch)

(6) Diameter of a new rod ... 44.45 + 0.00 - 0.05 mm (1.750 + 0.00 - 0.002 inch)

(7) Relief valve setting ... 19300 ± 170 kPa (2800 ± 25 psi)

(8) Diameter of a new bush ... 44.50 + 0.03 - 0.00 mm (1.752 + 0.001 - 0.000 inch)

Tailgate Mounting

Illustration 21	g00945554

(1) Inside diameter of a new bearing after assembly ... 95.385 ± 0.0838 mm (3.7553 ± 0.0033 inch)

(2) Pin diameter ... 95.22 ± 0.05 mm (3.749 ± 0.002 inch)

(3) Torque for the bolt ... 810 ± 100 N·m (600 ± 75 lb ft)

(4) Pin Length ... 194.8 mm (7.67 inch)

Note: For collet removal, use three 5P-5265 Forcing Bolts .

Note: Apply 5P-0960 Molybdenum Grease to the pin bores. Apply 5P-3931 Anti-Seize Compound (High Temperature) to the inside and to the outside diameters of all collets. Apply 5P-3931 Anti-Seize Compound (High Temperature) to all collet fastening bolts.

Procedure to Install the Tailgate Pin and Collet Assemblies

1. Clean the bores in the tailgate and body brackets. Apply 5P-0960 Molybdenum Grease to the pin bores before assembly.

2. Attach a hoist and suitable lifting chains to the tailgate. Position the tailgate so that the tailgate bores and the body bracket bores are aligned. The weight of the tailgate is 980 kg (2160 lb).

3. Clean the tailgate pins. Install the tailgate pins through the aligned bores. The pins must be positioned centrally in the bores.

4. Clean the inside and outside diameters of the collets. Apply 5P-3931 Anti-Seize Compound (High Temperature) to the inside and outside diameters of the collets. Position a collet on each end of the pins.

   Note: The threaded collets must be located inside the inner body brackets.

5. Apply 5P-3931 Anti-Seize Compound (High Temperature) to the threads of the bolts that secure the pin assemblies. Install a washer on each bolt and install the bolts through the pins.

6. Tighten bolt (3) as follows:

   1. Tighten the bolt to a torque of 1350 ± 160 N·m (1000 ± 120 lb ft).

   2. Strike each collet with a heavy hammer until the torque of the bolt is less than 680 N·m (500 lb ft).

   3. Tighten the bolt again to a torque of 1350 ± 160 N·m (1000 ± 120 lb ft).

   4. Strike each collet again with a heavy hammer until the torque of the bolt is less than 1020 N·m (750 lb ft).

   5. Tighten the bolt to a final torque of 1350 ± 160 N·m (1000 ± 120 lb ft).

      Note: 50 service hours after any pin and collet was installed, tighten the bolt in each collet to a torque of 1350 ± 160 N·m (1000 ± 120 lb ft).

Flow Control Valve (Retract)

Illustration 22	g00952209

(1) Torque to install the valve ... 465 to 500 N·m (345 to 370 lb ft)

(2) Torque to install the check valve ... 465 to 500 N·m (345 to 370 lb ft)

Sequence Valve (Ejector)

Illustration 23	g01675257

(1) Torque to install the check valve ... 200 to 215 N·m (150 to 160 lb ft)

(2) Torque to install the check valve ... 45 to 50 N·m (33 to 37 lb ft)

(3) Torque to install the check valve ... 200 to 215 N·m (150 to 160 lb ft)

(4) Torque to install the check valve ... 200 to 215 N·m (150 to 160 lb ft)

(5) Torque to install the eject circuit sequence valve ... 45 to 50 N·m (33 to 37 lb ft)

Ensure the tailgate is fully lowered before the ejector plate moves.

Maximum pressure to open the eject circuit sequence valve is relief valve pressure setting less ... 345 kPa (50 psi)

Minimum pressure to open the eject circuit sequence valve is ... 12400 kPa (1800 psi)

ReferenceFor the relief valve pressure setting, refer to Specifications, "Control Valve (Hoist)."

(6) Torque to install the retract circuit sequence valve ... 200 to 215 N·m (150 to 160 lb ft)

Ensure the ejector plate has retracted a minimum of half the length of the body before the tailgate raises.

Maximum pressure to open the retract circuit sequence valve is relief valve pressure setting less ... 345 kPa (50 psi)

ReferenceFor the relief valve pressure setting, refer to Specifications, "Control Valve (Hoist)."

(7) Torque to install the check valve ... 465 to 500 N·m (350 to 375 lb ft)

Ejector Body

Illustration 24	g00945900

Illustration 25	g00946136

(1) Clearance between ejector plate (2) and body (3)

new ... 12.0 mm (0.47 inch)

minimum ... 6.0 mm (0.24 inch)

Wear plate (4) must be replaced when clearance (1) is less than 6.0 mm (0.24 inch).

Note: Failure to replace wear plates (4) at this stage of wear may result in premature wear of the ejector cylinders.

Note: All other ejector body wear plates should be replaced when the plate is worn to within 6.0 mm (0.24 inch) of the parent metal.

(5) Locate this edge 5.0 mm (0.20 inch) short of the full extension of the ejector plate.

(6) Distance from bottom of ejector body stop plate to measuring point (7) ... 150 mm (6 inch)

(7) Stop plate width measured at point (6)

new ... 37 mm (1.46 inch)

minimum ... 33 mm (1.30 inch)

Stop plate thickness measured from body

new ... 20 mm (0.79 inch)

minimum ... 10 mm (0.39 inch)

Systems Operation Section

Hydraulic System

General Information

Illustration 26	g01235781
Ejector hydraulic system schematic (1) Retract flow control valve (2) Manifold (3) Ejector sequence valve (4) Ejector cylinder (5) Tailgate cylinder (6) Cross-line relief valve (7) Ejector cylinder rod end pressure tap (8) Ejector cylinder head end pressure tap (9) Hoist control valve (10) Retract pressure relief valve (11) Brake oil cooler relief valve (12) Stem (13) Eject pressure relief valve (14) Line to brake oil cooling (15) Line to the steering metering pump (16) Centering springs (17) Screen (18) Pilot system pressure tap (19) Main relief dump valve (20) Hoist proportioning solenoid for eject (21) Stem (22) Line to the parking brake control valve (23) Check valve (24) Hydraulic tank breather (25) Brake cooling and hoist section of the gear pump (26) Hoist proportioning solenoid for hold and retract (27) Check valve (28) Pilot oil pressure reducing valve (29) Hydraulic tank (30) Brake and pilot section of the gear pump (31) Pilot oil filters

Illustration 27	g01239568
(1) Retract flow control valve (3) Ejector sequence valve (4) Ejector cylinder (5) Tailgate cylinder (6) Cross-line relief valve (9) Hoist control valve (25) Brake cooling and hoist section of the gear pump (29) Hydraulic tank (30) Brake and pilot section of the gear pump

Hoist Control

Illustration 28	g00938105
Hoist Control (1) RETRACT Position (2) HOLD Positions (3) EJECT Position

The hoist control is located on the transmission shift console on the right side of the operator station. The hoist control has four positions; EJECT, RETRACT and two HOLD positions. The machine should normally be operated with the hoist control in one of the HOLD positions.

The hoist control is connected to the hoist control position sensor. The hoist control position sensor sends electrical signals to the Power Train/Chassis Electronic Control Module (Power Train/Chassis ECM).

When the hoist control is released a spring will move the hoist control from the EJECT position to a HOLD position, or from the RETRACT position to a HOLD position.

ReferenceFor more information on the hoist control position sensor, refer to Systems Operation, Testing and Adjusting, "Position Sensor (Hoist Control)".

Control Valve (Hoist)

Illustration 29	g01235731
(9) Hoist control valve (10) Retract pressure relief valve (11) Brake oil cooler relief valve (13) Eject pressure relief valve (20) Hoist proportioning solenoid for eject (26) Hoist proportioning solenoid for hold and retract (32) Actuator

Illustration 30	g01235752
(9) Hoist control valve (13) Eject pressure relief valve (16) Centering springs (20) Hoist proportioning solenoid for eject (21) Stem (26) Hoist proportioning solenoid for hold and retract (32) Actuator

Illustration 31	g01235770
(9) Hoist control valve (10) Retract pressure relief valve (11) Brake oil cooler relief valve (12) Stem (13) Eject pressure relief valve (19) Main relief dump valve

Oil flows from brake and pilot pump section (30) of the gear pump through check valve (27) to pilot oil pressure reducing valve (28). Pilot oil pressure reducing valve (28) maintains a constant pilot oil pressure to the parking brake, and to the steering and hydraulic pilot circuits. From the pilot oil pressure reducing valve, the pilot oil flows through pilot oil filter (31). This pilot oil flow is then divided.

Pilot oil flows to the steering metering pump through line (15) and to the parking brake circuit through check valve (23) and line (22). Also, pilot oil flows to hoist proportioning solenoids (20) and (26). Pilot oil is always present at both ends of stem (21) .

Hoist proportioning solenoids (20) and (26) are used to drain the pilot oil from the ends of stem (21), which then allows the stem to move.

Oil flows from hoist and brake cooling pump section (25) of the gear pump to hoist control valve (9). Hoist control valve (9) will direct pump oil to one of two locations. When the ejector body is being ejected or retracted, ejector cylinders (4) and tailgate cylinders (5) receive the oil. If the ejector is not being used, the oil flows to the oil cooling system for the brakes.

Brake oil cooler relief valve (11) limits the pressure in the brake oil cooling system. Brake oil cooler relief valve (11) will return oil to hydraulic tank (29) when brake oil cooling pressure is too high.

Retract pressure relief valve (10) limits the pressure to the rod end of ejector cylinders (4) when the body is being retracted. Retract pressure relief valve (10) will open when the pressure in the rod end of ejector cylinders (4) becomes too high. When retract pressure relief valve (10) opens, main relief dump valve (19) will open and oil will return to hydraulic tank (29) .

When the ejector body is being ejected, oil is sent to stem (12). Stem (12) will move against spring force. Eject pressure relief valve (13) will now limit the pressure to the head end of ejector cylinders (4). Eject pressure relief valve (13) will open when the pressure in the head end of ejector cylinders (4) becomes too high. When eject pressure relief valve (13) opens, main relief dump valve (19) will open and oil will return to hydraulic tank (29) .

HOLD Position

In the HOLD position, neither of the hoist proportioning solenoids are receiving current. The pilot oil is blocked by actuators (32). Centering springs (16) hold stem (21) so that oil in the head end of ejector cylinders (4) is blocked by stem (21) .

Stem (21) is in a position that allows all of the pump oil to flow to the brake cooling system through brake oil cooler relief valve (11). The maximum pressure in the brake cooling system is controlled by brake oil cooler relief valve (11). If brake oil cooler relief valve (11) opens, the oil will return to hydraulic tank (29) .

EJECT Position

In the EJECT position, hoist proportioning solenoid (20) is receiving a current of 1.9 amperes. Pilot oil in actuator (32) for hoist proportioning solenoid (20) is allowed to drain to hydraulic tank (29). Pilot oil in actuator (32) for hoist proportioning solenoid (26) will now push stem (21) towards hoist proportioning solenoid (20). When stem (21) moves, the pump oil from hoist and brake cooling pump (25) flows through hoist control valve (9) to ejector sequence valve (3), and the head end of tailgate cylinders (5) .

Some of the oil is also sent as signal oil to stem (12). The signal pressure moves stem (12) so that retract pressure relief valve (10) is blocked. This allows all of the pump oil that is flowing through main relief dump valve (19) to flow to eject pressure relief valve (13). If the oil pressure opens eject pressure relief valve (13), main relief dump valve (19) will open and the pump oil will be returned to hydraulic tank (29) .

RETRACT Position

In the RETRACT position, hoist proportioning solenoid (26) is receiving a current of 1.9 amperes. Pilot oil in actuator (32) for hoist proportioning solenoid (26) is allowed to drain to hydraulic tank (29). Pilot oil in actuator (32) for hoist proportioning solenoid (20) will now push stem (21) towards hoist proportioning solenoid (26). When stem (21) moves, the pump oil from hoist and brake cooling pump (25) flows through hoist control valve (9) to retract flow control valve (1), ejector sequence valve (3), and the rod end of ejector cylinders (4) .

Because no signal pressure is sent to stem (12), pump oil can flow to retract pressure relief valve (10). If retract pressure relief valve (10) opens, main relief dump valve (19) will open and the pump oil will return to hydraulic tank (29) .

Ejector Cylinder

Illustration 32	g00946842
(1) Cylinder head (2) Chamber (3) Cylinder (4) Cylinder (5) Cylinder (6) Cylinder (7) Cylinder (8) Cylinder rod (9) Oil inlet for eject oil (10) Oil inlet for retract oil (11) Passage (12) Chamber (13) Holes

The ejector cylinder is a four stage telescopic cylinder.

Two telescoping, hydraulic cylinders are used to move the ejector plate along the body. The cylinders have self-aligning bearings at both head and rod ends. The head ends of the cylinders are pin-mounted to the ejector plate and the rod ends of the cylinders are pin-mounted to the machine frame.

The ejector cylinders operate in tandem. When the hoist control lever is held in the EJECT position, the cylinders extend and the ejector plate moves rearwards to eject the load. When the hoist control lever is held in the RETRACT position, the cylinders retract and the ejector plate moves forward to the RETRACTED position. When the hoist control lever is released, the lever returns to the HOLD position and cylinder extension or retraction stops immediately.

The ejector cylinders operate in sequence with the tailgate cylinders. The ejector plate will only operate when the tailgate is in the fully DOWN position. The tailgate will only operate when the ejector plate has retracted.

The ejector cylinders extend in four stages. Pump oil goes into opening (9) and travels through the hollow center of rod (8) into chamber (2). The pressure of the pump oil in chamber (2) exerts force on head (1) to extend outer cylinder (3). When cylinder (3) reaches the end of its travel it acts to extend cylinder (4). This telescoping process continues until cylinder (6) reaches the end of its travel along cylinder (7) .

Maximum cylinder extension occurs when the ejector plate contacts stops welded to the body.

The ejector cylinders retract in four stages. Pump oil goes into opening (10) and travels through passages in rod end (11) into chamber (12). The oil then travels through holes (13) to fill the cavities between the cylinders. The pressure of the pump oil in these cavities causes the ejector cylinders to retract.

Tailgate Cylinder

Illustration 33	g00952204
(1) Manifold (2) Make up valve (3) Locknut (4) Adjusting screw (5) Cross-line relief valve for the head end of the tailgate cylinder (6) Make up valve (7) Cross-line relief valve for the rod end of the tailgate cylinder

The tailgate cylinders control the position of the tailgate. There is a tailgate cylinder on each side of the tailgate. The tailgate cylinders incorporate cross-line relief valves (5) and (7) for both the head and rod ends of each cylinder. Cross-line relief valve (5) is for the head end of the cylinder. Cross-line relief valve (7) is for the rod end of the cylinder. There is also make up valves (2) and (6) for the rod and head ends of each cylinder. The valves are located in manifold (1) on the ejector cylinder.

To lower the tailgate, oil pressure is directed to the head end of the tailgate cylinder. The cylinder is extended and the tailgate lowers. To raise the tailgate, oil pressure is directed to the rod end of the tailgate cylinder. The cylinder is retracted and the tailgate raises.

If an external force acts on the tailgate, the tailgate will attempt to move. The force is transferred to the cylinder and the oil pressure in the cylinder will increase. If the oil pressure becomes too high, cross-line relief valve (5) or (7) will open and allow oil to flow to the opposite end of the cylinder. If the amount of oil flowing to the opposite end of the cylinder is not sufficient, a decrease in pressure in the cylinder will cause make up valve (2) or (6) to open.

Oil from the hydraulic tank can now flow to the cylinder and prevent cavitation in the cylinder.

Cross-line relief valves (5) and (7) are adjusted by screw (4). To adjust the pressure setting of the relief valve, loosen locknut (3). Turn the screw clockwise for an increase in pressure and counter clockwise for a decrease in pressure.

ReferenceFor the cross-line relief valve pressure setting, refer to ""Specifications" ", ""Tailgate Cylinder" ".

Flow Control Valve (Retract)

Illustration 34	g01234535

The retract flow control valve is located in a manifold on the right side of the rear frame.

Illustration 35	g01184927
(1) Port (2) Retract flow control valve (3) Port (4) Port (5) Check valve

The retract flow control valve controls the oil flow from the hoist control valve to the ejector sequence valve when the hoist control valve is in the RETRACT position.

During the retract cycle, oil from the hoist control valve enters the manifold through port (3). Oil flow is regulated by retract flow control valve (2) before exiting through port (4) to the ejector sequence valve. As pressure increases, retract flow control valve (2) moves against spring force and allows excess oil to return to the hydraulic tank through port (1) .

Sequence Valve (Ejector)

Illustration 36	g01234549
Location of the ejector sequence valve

Ejector sequence valve (1) is located on the right side of the rear frame.

Illustration 37	g01241353
(1) Ejector sequence valve (2) Port for rod end of ejector cylinder (3) Port for eject circuit (4) Port for retract circuit (5) Port for rod end of ejector cylinder (6) Check valve (7) Port for head end of ejector cylinder (8) Pilot-to-open check valve (9) Port for return to tank oil (10) Pilot-to-close check valve (11) Retract sequence valve (12) Port for head end of ejector cylinder (13) Eject sequence valve (14) Port for return to tank oil (15) Port for tailgate cylinder (16) Pilot-to-open check valve (17) Pilot-to-open check valve (18) Port for tailgate cylinder (19) Pilot-to-open check valve

The sequence function of the ejector sequence valve controls the movement of the tailgate cylinders in relation to the ejector cylinders.

When the hoist control valve is moved to the EJECT position, oil will be directed to the tailgate cylinders to lower the tailgate fully. Only after the tailgate is fully lowered will oil be directed to the ejector cylinders to move the ejector plate and eject the load. This prevents damage to the tailgate.

When the hoist control valve is moved to the RETRACT position, oil is first directed to the ejector cylinders to retract the ejector plate. When the ejector plate is close to being fully retracted, oil will be directed to the tailgate cylinders to raise the tailgate.

Sequence Valve (Eject)

Illustration 38	g01240588
Ejector sequence valve schematic (1) Ejector sequence valve (2) Port for rod end of ejector cylinder (3) Port for eject circuit (4) Port for retract circuit (5) Port for rod end of ejector cylinder (6) Check valve (7) Port for head end of ejector cylinder (8) Pilot-to-open check valve (9) Port for return to tank oil (10) Pilot-to-close check valve (11) Retract sequence valve (12) Port for head end of ejector cylinder (13) Eject sequence valve (14) Port for return to tank oil (15) Port for tailgate cylinder (16) Pilot-to-open check valve (17) Pilot-to-open check valve (18) Port for tailgate cylinder (19) Pilot-to-open check valve (20) Check valve (21) Check valve (22) Orifice

Eject sequence valve (13) is located in ejector sequence valve (1) on the right side of the rear frame.

Eject sequence valve (13) is a direct acting valve that controls the eject circuit for the ejector cylinders and the tailgate cylinders.

When the hoist control valve stem moves to the EJECT position, oil will be directed to port (3) of ejector sequence valve (1). Pilot-to-open check valves (16) and (19) block oil flow to ports (7) and (12) and to the ejector cylinders. Oil from port (3) is free to flow to the head end of the tailgate cylinders through port (18). Orifice (22) restricts the flow of oil to port (18), controlling the speed of the tailgate cylinders.

Oil flow from the rod end of the tailgate cylinders enters ejector sequence valve (1) through port (15) and is blocked by pilot-to-open check valve (17). This will cause oil pressure in the eject circuit to increase. The pressure increase in the eject circuit will open pilot-to-open check valve (17) and allow oil from the tailgate cylinder to flow through check valve (21) to port (4). Oil from port (4) then returns through the hoist control valve to the brake cooling system.

When the tailgate is fully lowered there will be an increase in pressure in the eject circuit. The increase in pressure will open eject sequence valve (13). Oil will flow through eject sequence valve (13) and check valve (8) to pilot-to-open check valves (16) and (19). The oil at port (3) flows through pilot-to-open check valve (16) and (19), and through ports (7) and (12). The oil then flows to the head end of the ejector cylinders. The ejector cylinders extend and move the ejector plate to eject the load.

Oil from the rod end of the ejector cylinders enters ejector sequence valve (1) through ports (2) and (5). The oil flow is stopped by check valve (6). The oil flows through pilot-to-close check valve (10). This oil now supplements the oil flow to the head end of the ejector cylinders via ports (7) and (12) .

Port (9) returns drain oil from eject sequence valve (13) to the hydraulic tank.

ReferenceFor information on adjusting the eject sequence valve, refer to ""Testing and Adjusting Section" ", ""Eject Sequence Valve" ".

Sequence Valve (Retract)

Illustration 39	g01240588
Ejector sequence valve schematic (1) Ejector sequence valve (2) Port for rod end of ejector cylinder (3) Port for eject circuit (4) Port for retract circuit (5) Port for rod end of ejector cylinder (6) Check valve (7) Port for head end of ejector cylinder (8) Pilot-to-open check valve (9) Port for return to tank oil (10) Pilot-to-close check valve (11) Retract sequence valve (12) Port for head end of ejector cylinder (13) Eject sequence valve (14) Port for return to tank oil (15) Port for tailgate cylinder (16) Pilot-to-open check valve (17) Pilot-to-open check valve (18) Port for tailgate cylinder (19) Pilot-to-open check valve (20) Check valve (21) Check valve (22) Orifice

Retract sequence valve (11) is located in ejector sequence valve (1) on the right side of the rear frame.

Retract sequence valve (11) is a direct acting valve that controls the retract circuit for the ejector cylinders and the tailgate cylinders.

When the hoist control valve stem moves to the RETRACT position, oil will be directed to port (4). Retract sequence valve (11) and check valve (21) blocks oil flow to port (15) and the rod end of the tailgate cylinders. Oil flows through check valve (6) and ports (2) and (5) to the rod end of the ejector cylinders. Ejector cylinders begin to retract and move the ejector plate. Oil pressure in the retract circuit holds pilot-to-close check valve (10) in the closed position. Pilot-to-close check valve (10) blocks oil flow to port (3) .

When the ejector cylinders are close to being fully retracted, the pressure in the retract circuit increases. The pressure increase causes retract sequence valve (11) to open. Oil will flow through pilot-to-open check valve (17) and port (15) to the rod end of the tailgate cylinders. The tailgate will now close.

Oil from the head end of the ejector cylinders enters ejector sequence valve (1) through ports (7) and (12) and through pilot-to-open check valve (16) and (19). The oil then flows to port (3) and returns to the hydraulic tank.

Port (9) returns drain oil from retract sequence valve (11) to the hydraulic tank.

ReferenceFor information on adjusting the retract sequence valve, refer to ""Testing and Adjusting Section" ", ""Retract Sequence Valve" ".

Testing and Adjusting Section

Hydraulic System

Cylinder Operation Test

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine or release of oil pressure can cause injury to persons on or near the machine. To help prevent possible injury or death, refer to the information in Testing and Adjusting, "Machine Preparation for Troubleshooting".

The operation tests can be used to find leakage in the system. They can also be used to find a faulty valve or pump. The speed of rod movement when the cylinders move can be used to check the condition of the cylinders and the pump.

Eject and retract the body several times. Operate the hoist control until the cylinders are fully extended and retracted several times. Ensure the temperature of the oil is above 38 °C (100 °F).

(1) Watch the cylinders as they are extended and retracted. Movement must be smooth and regular.

(2) Check for noise from the brake cooling and hoist pump.

• Allow the cylinders to travel full stroke in each direction.

• Check the tailgate cylinders for excessive cylinder drift.

• Check for the sound of the relief valve opening. Refer to Testing and Adjusting, "Relief Valve (Hoist Control Valve) - Test" for the opening pressure of the relief valve.

Ejector Cylinder Speed Test

Start the engine and run the engine at high idle rpm. Move the hoist control lever to the EJECT position. Hold the hoist control lever in EJECT position for 5 seconds after the cylinders are fully extended, then retract the body. Repeat this cycle many times to get the temperature of the hydraulic oil to more than 38 °C (100 °F).

Retract the body fully with the tailgate raised. With the engine running at high idle speed, measure the time for the body to eject from the fully retracted position to the fully ejected position.

Refer to table 3 for the time for the cylinders to fully eject the body.

Table 3

Ejector Cylinder Speed
Time to fully eject	22.0 ± 5.0 Second
Time to fully retract	30.0 ± 5.0 Second

Tailgate Cylinder Drift Test

Start the engine and eject and retract the body many times to get an increase in the temperature of the hydraulic oil. The temperature of the hydraulic oil must be no less than 38 °C (100 °F)

Fully retract the ejector body, ensuring the tailgate is fully against the tailgate stop.

Shut off the engine and take measurements from the tailgate stop to the tailgate at 5 minute intervals. The maximum allowable cylinder drift is shown in table 4.

Table 4

Tailgate Cylinder Drift
Time Interval	Allowable Movement
5 Minutes	15.0 mm (0.60 inch)
10 Minutes	20.0 mm (0.80 inch)
15 Minutes	30.0 mm (1.20 inch)

Sequence Valve (Ejector) - Test and Adjust

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine or release of oil pressure can cause injury to persons on or near the machine. To help prevent possible injury or death, refer to the information in Testing and Adjusting, "Machine Preparation for Troubleshooting".

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "AVSpare Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on AVSpare products. Dispose of all fluids according to local regulations and mandates.

Eject Sequence Valve

When the eject sequence valve is correctly adjusted, the eject cycle will occur in the correct sequence. When the body is ejected from the fully retracted position, the tailgate should first open fully before the ejector plate starts to move.

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NOTICE
Damage to the ejector body or ejector body tailgate may occur if the eject cycle sequence is not correct.

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Illustration 40	g00953518
Location of the pressure tap (1) Pressure tap

1. Connect a hose assembly with a 0 to 41500 kPa (0 to 6000 psi) pressure gauge to pressure tap (1) on the manifold.

2. Start the engine and eject and retract the body many times to get the temperature of the hydraulic oil to more than 38 °C (100 °F). Fully retract the ejector body. The tailgate should be fully raised.

3. Move the hoist control lever in the operator station to the EJECT position and observe the gauge. The tailgate should start to lower.

4. When the tailgate is fully lowered, the pressure on the gauge at pressure tap (1) should increase to a maximum and then lower to approximately 3450 kPa (500 psi) as the ejector plate starts to move. The maximum pressure shown on the gauge is the eject sequence valve pressure. Refer to Table 5 for the correct eject sequence valve pressure setting.
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   Table 5

   Eject Circuit Sequence Valve Pressure
   Maximum pressure to open the eject circuit sequence valve	16200 kPa (2350 psi)
   Minimum pressure to open the eject circuit sequence valve	12400 kPa (1800 psi)

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Illustration 41	g00953898
Location of the ejector sequence valve (2) Eject sequence valve

5. If the sequence valve setting is not correct, adjust eject sequence valve (2). Loosen the locknut on the valve and turn the adjusting screw clockwise for an increase and counterclockwise for a decrease in the pressure setting. When the pressure setting is correct, tighten the locknut. Check the operation of the eject sequence. Ensure the tailgate is fully lowered before the ejector plate moves. If necessary, readjust the eject sequence valve within the minimum and maximum pressure settings.

Retract Sequence Valve

When the retract sequence valve is correctly adjusted, the retract cycle will occur in the correct sequence. When the body is retracted from the fully ejected position, the ejector plate should retract a minimum of half the length of the body before the tailgate starts to raise.

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NOTICE
Damage to the ejector body or ejector body tailgate may occur if the retract cycle sequence is not correct.

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Illustration 42	g00953902

1. Connect a hose assembly with a 0 to 41500 kPa (0 to 6000 psi) pressure gauge to pressure tap (3) on the manifold.

2. Start the engine and eject and retract the body many times to get the temperature of the hydraulic oil to more than 38 °C (100 °F). Fully eject the ejector body. The tailgate should be fully lowered.

3. Move the hoist control lever in the operator station to the RETRACT position and observe the gauge. The ejector body should start to retract. When the ejector body is near the fully retracted position, the pressure on the gauge at pressure tap (3) should increase to a maximum as the tailgate starts to raise. The maximum pressure shown on the gauge is the retract sequence valve pressure. Refer to Table 6 for the correct eject sequence valve pressure setting.
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   Table 6

   Retract Circuit Sequence Valve Pressure
   Maximum pressure to open the retract circuit sequence valve	16200 kPa (2350 psi)
   Minimum pressure to open the retract circuit sequence valve	10000 kPa (1450 psi)

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Illustration 43	g00953905
Location of the retract sequence valve (4) Retract sequence valve

4. If the sequence valve setting is not correct, adjust sequence valve (4). Loosen the locknut on the valve and turn the adjusting screw clockwise for an increase or counterclockwise for a decrease in the pressure setting. When the pressure setting is correct, tighten the locknut. Check the operation of the retract sequence. Ensure the ejector plate has retracted a minimum of half the length of the body before the tailgate raises. If necessary, readjust the retract sequence valve within the minimum and maximum pressure settings.