HOSE 3949781 - Caterpillar

Standard Tooling
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Table 2 provides a list of the required tools if standard tooling is used to perform the following test procedure.
Table 2
Required Tools (Standard Tooling)    
Tool    Item    Part Number    Description    Qty    
B     B1     177-7860     Hose As     1    
B2 6V-4143     Coupler     2    
C     C1     8T-0855     Pressure Gauge
0 - 4000 kPa (0 - 580 psi)     2    
6V-3989 Fitting 2    
C2 8T-0651     Pressure Gauge
0 - 60000 kPa (0 - 8700 psi)     2    
6V-3989 Fitting     2    
C3 177-7860     Hose As     2    
6V-4143 Coupler     4    
D     D1     6V-9507     Face Seal Plug     2    
D2 6V-9828     Cap As     2    Note: This test is performed on the axle propel pump. This test will need to be repeated for the drum propel pump.Before conducting the testing and adjusting on the servo valve, the following steps must be performed:
Apply the parking brake.
Place the propel control lever in NEUTRAL.
Place the machine in a position against a solid, stationary object such as a loading dock.Test Procedure
A combination of the 198-4240 Digital Pressure Indicator and Standard Tooling was used in the following test.
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Drum and Axle Propel Pumps (1) Pressure taps for axle propel pump (2) Balance lines (3) Pressure taps for the drum propel pump (4) Neutral adjustment screw for the servo piston
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(5) X1 and X2 test ports
Connect Tool (B) between the X1 and X2 ports (5). This makes equal oil pressure on each side of the servo piston.Note: If you use the gauges from the standard tooling, check the pressures in Step 2 with Tool (C2) .
Connect Tool (A) into each pressure tap (1) .
With the speed range switch in LOW SPEED range, start the engine and run the engine at 1200 50 rpm at low idle.
Look at the pressure readings. The pressures should be equal.
Stop the engine. If the pressures are equal, remove all tooling. If the pressures are not equal, the NEUTRAL position of the pump will need to be adjusted.Adjusting Procedure
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Servo Valve (Piston Pump) (6) Locknut
Stop the engine.
If it is necessary to adjust the neutral position of the piston, loosen locknut (6). Use an allen wrench to turn the neutral adjustment screw for the servo piston. Turn the screw clockwise or counterclockwise in order to adjust the mechanical center of the servo.
Start the engine. Check the pressure readings. The pressure on the gauges should change. Repeat steps 1 through 2 until the two pressures are equal.Note: If you use the gauges from the standard tooling, recheck your pressures with Tool (C1) .
Tighten locknut (6). Remove all of the test equipment.Note: Perform this procedure on the drum propel pump in the same manner as the axle propel pump. Read the measurements from the pressure taps that are on drum propel pump (3). The drum propel pump