BLADE & EDGE GP 9U8088 - Caterpillar

Before any tests are performed, prepare the machine for troubleshooting. Refer to Testing and Adjusting, "Machine Preparation". Before any tests are performed, visually inspect the machine for oil leaks and damaged parts. Refer to Testing and Adjusting, "Visual Inspection". The pilot system pressure test determines the pressure to the joystick controls. The charge pump section of the gear pump supplies the pilot oil.
Engage the parking brake. Stop the engine.
Block the wheels of the machine.
Raise the cab. Refer to the Operation and Maintenance Manual, "Cab Support Operation".
Illustration 1 g01355400
(1) Charge pressure tap
Install a 6V-4143 Quick Connect Coupler to each end of 177-7861 Hose. Install the 6V-3989 Fitting to the 8T-0856 Pressure Gauge. Connect the pressure gauge to the charge pressure tap (1) by using the hose and coupler assembly.
Illustration 2 g01364317
(2) Supply line for the work tool joystick control
Install a 6V-3965 Fitting As to the end of supply line (2) by using the 7X-2444 Tee. Use a 6V-5049 O-Ring Seal when you install the tee. Use a 3J-1907 O-Ring Seal when you connect the fitting assembly to the tee. The supply line is for the pilot operated hydraulic control ( work tool).
Install a 6V-4143 Quick Connect Coupler to each end of the 177-7861 Hose As. Install the 6V-3989 Fitting to the 8T-0856 Pressure Gauge. Connect the pressure gauge to the pressure tap (2) on the pilot operated hydraulic control (work tool). Use the hose and coupler assembly.
Secure the three hydraulic lines so that the pressure gauges can be viewed by the operator during the test. The hoses should not be pinched when the cab is lowered.
Lower the cab.
Sit in the operator's seat. Fasten the seat belt and lower the armrest.
Start the engine. Disengage the parking brake.
Run the engine at LOW IDLE. Record the charge pressure and pilot pressure.
Table 2
248B/ 268B     Low Idle    
Charge Pressure    
3100 200 kPa (450 29 psi)    
Pilot Pressure    
3100 200 kPa (450 29 psi)    
For all machines, set the engine RPM to the specifications in the table below. Record the charge pressure and pilot pressure.
Table 3
Model     Engine RPM    
248B/ 268B     2300 25 RPM    
Table 4
248B/ 268B     2300 25 RPM    
Charge Pressure    
3225 200 kPa (468 29 psi)    
Pilot Pressure    
3225 200 kPa (468 29 psi)    
Reduce the engine to LOW IDLE. Stop the engine.
Raise the cab. Remove the test equipment.
Lower the cab. Refer to the Operation and Maintenance Manual, "Cab Support Operation". Remove the blocks.Brake Test
This test will determine if the brakes are functioning correctly. This test will check the solenoid valve ( brake) and the piston motor.
Raise the cab. Refer to Operation and Maintenance Manual, "Cab Support Operation".
Illustration 3 g00790186
Disconnect electrical connection (1) for brake solenoid (2) .
Illustration 4 g00790283
Install a 7X-2444 Tee (3) and a 6V-3965 Valved Nipple Assembly (4) in the hydraulic line that runs from the brake solenoid to the piston motors.
Install a 8T-0855