2009/10/16 Correction to Systems Operation Testing and Adjusting , "Pressure Reducing Valve (Pilot Oil) - Test and Adjust" {5117} Caterpillar

Underground Articulated Truck:

AD30 (S/N: DXR367-UP)

Systems Operation Testing and Adjusting, RENR8542, "AD30 Underground Articulated Truck Steering System", "Pressure Reducing Valve (Pilot Oil) - Test and Adjust". This module is part of Service Manual, RENR8520 Volume II.Systems Operation Testing and Adjusting, RENR8543, "AD30 Underground Articulated Truck Braking System", "Pressure Reducing Valve (Pilot Oil) - Test and Adjust". This module is part of Service Manual, RENR8520 Volume II.Systems Operation Testing and Adjusting, RENR8544, "AD30 Underground Articulated Truck Hydraulic System", "Pressure Reducing Valve (Pilot Oil) - Test and Adjust". This module is part of Service Manual, RENR8520 Volume II.

Additional information is available for the above modules. A new pilot oil pressure reducing valve is now used in AD30 (S/N: DXR367-UP). Add this information to the above modules.

Pressure Reducing Valve (Pilot Oil) - Test and Adjust

Table 1

Required Tools
Part Number	Part Description	Qty
177-7861	Hose As	1
6V-4143	Coupler	2
8T-0856	Pressure Gauge (0 to 6,000 kPa (0 to 870 psi))	1

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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

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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 machine. 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 Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in AVSpare machines. Dispose of all fluids according to local regulations and mandates.

Illustration 1	g00935397
Location of the pressure tap (1) Pressure tap for the pilot hydraulic system

1. Remove the protective cover from pressure tap (1). Connect a hose assembly with an 8T-0856 Pressure Gauge (0 to 6,000 kPa (0 to 870 psi)) to pressure tap (1) .

2. With the parking brake engaged, start the engine and maintain engine speed above 1500 rpm with the transmission in NEUTRAL.

3. Observe the pressure on the gauge. The pressure reading on the gauge with the oil at normal operating temperature should be 3620 ± 70 kPa (525 ± 10 psi).

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Illustration 2	g01176841
Location of the pilot oil pressure reducing valve (Typical example) (2) Pilot oil pressure reducing valve

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Illustration 3	g01972993
(2) Pilot oil pressure reducing valve (3) Locknut (4) Adjusting screw

4. If the pressure reading is not correct, stop the engine. Loosen locknut (3) and turn adjusting screw (4) on pilot oil pressure reducing valve (2). Turn adjusting screw (4) clockwise to increase the pressure, and counterclockwise to decrease the pressure. Tighten locknut (3) to 12 ± 2 N·m (9 ± 1.5 lb ft).

5. Repeat Step 2 through Step 4 until the correct pressure setting is obtained.

6. When this test is complete, stop the engine and remove the test equipment. Place the protective cover on the pressure tap.