2004/11/08 Caterpillar

Skid Steer Loader:

248B (S/N: SCL1-UP)

268B (S/N: LBA1-UP)

Testing and Adjusting, RENR8747, "248B and 268B Skid Steer Loader Machine Systems". This module is part of Service Manual, RENR8742.

Reference: Operation and Maintenance Manual, SEBU7731, "216B, 226B, 232B, 236B, 242B, 246B, 248B, 252B, 262B and 268B Skid Steer Loaders"

The following procedure for testing and adjusting the high flow XPS auxiliary hydraulic system pressure should be added to Testing and Adjusting, RENR8747.

High Flow XPS Auxiliary Hydraulic System Pressure - Test

Table 1

REQUIRED TOOLS
Part Number	Description	Qty
177-7861	Hose	2
6V-4143	Coupler Assemblies	2
8T-0860	Pressure Gauge (1)	1
6V-3989	Unvalved Nipple	1
1U-5793	Pressure Differential Gauge (2)	1

( 1 )	0 to 40000 kPa (5800 psi) Pressure Range
( 2 )	0 to 3500 kPa (508 psi) Pressure Range

Illustration 1	g01115237
(1) Pump load sense input (2) Margin pressure adjustment (3) XPS pressure adjustment (4) Pressure tap

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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 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, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

Margin Pressure

1. Raise the cab.

2. Install a 1U-5793 Pressure Differential Gauge between pressure tap (1) on the hydrostatic pump compensator and pressure tap (4) on the work tool control valve.

3. Lower the cab.

4. Start the machine. Run the engine at HIGH IDLE. Ensure that the hydraulic oil is at operating temperature.

5. Initiate the standard flow auxiliary hydraulic function. Record the pressure on the differential pressure gauge. The pressure should be 2400 ± 200 kPa (350 ± 30 psi).

6. If the pressure is not within the specification, use an allen wrench and adjust the pressure adjustment screw (2) .
   • To increase the margin pressure, turn the pressure adjustment screw inward.

   • To decrease the margin pressure, turn the pressure adjustment screw outward.

7. Recheck the margin pressure by repeating Step 4 through Step 6.

8. Reduce the engine speed to LOW IDLE. Stop the engine.

9. Release the auxiliary hydraulic system pressure.

10. Remove the differential pressure gauge.

High Pressure Cutoff

1. Raise the cab.

2. Install a 8T-0860 Pressure Gauge on pressure tap (4) on the work tool control valve.

3. Lower the cab.

4. Start the machine. Run the engine at HIGH IDLE. Ensure that the hydraulic oil is at operating temperature.

5. Initiate the XPS auxiliary hydraulic function. Record the pressure on the pressure gauge. The pressure should be 28000 ± 1000 kPa (4060 ± 145 psi).

6. If the pressure is not within the specification, use an allen wrench and adjust the pressure adjustment screw (3) .
   • To increase the high pressure cutoff, turn the pressure adjustment screw inward.

   • To decrease the high pressure cutoff, turn the pressure adjustment screw outward.

7. Recheck the high pressure cutoff by repeating Step 4 through Step 6.

8. Reduce the engine speed to LOW IDLE. Stop the engine.

9. Release the auxiliary hydraulic system pressure.

10. Remove the pressure gauge.