938G Series II Wheel Loader and IT38G Series II Integrated Toolcarrier Hydraulic System Piston Pump (Hydraulic Fan) Caterpillar

Illustration 1	g00918716
Piston Pump

The rotation of the shaft is counterclockwise when the pump is viewed from the shaft end.

Pump displacement for one revolution ... 28 cc (1.71 in³)

(1) 194-9472 Spring

Free length ... 53 mm (2.1 inch)

Outside diameter ... 21.3 mm (0.84 inch)

(2) Tighten the plug to the approximate torque. ... 190 N·m (140 lb ft)

(3) 155-9117 Spring

Free length ... 58 mm (2.28 inch)

Outside diameter ... 28.1 mm (1.12 inch)

(4) Apply 9S-3263 Thread Lock to the threads before assembly.

(5) 6E-3276 spring

Free length ... 35.6 mm (1.40 inch)

Outside diameter ... 19.2 mm (0.76 inch)

Load at assembly ... 462 ± 71 N (104 ± 16 lb)

(6) 193-1036 Spring

Free length ... 31.1 mm (1.23 inch)

Outside diameter ... 8.3 mm (0.327 inch)

(7) 6E-3274 spring

Free length ... 15.9 mm (0.63 inch)

Outside diameter ... 7.7 mm (0.30 inch)

Load at assembly ... 81.7 ± 14.5 N (18 ± 3.26 lb)

(8) 6E-3275 spring

Free length ... 20.5 mm (0.81 inch)

Outside diameter ... 10.7 mm (0.42 inch)

Load at assembly ... 40.2 ± 2.8 N (9 ± 0.63 lb)

(9) Grind the spacer to the required thickness. The spacer must be ground parallel to less than 0.05 mm (0.002 inch).

(10) Tighten the nut to the approximate torque. ... 21 N·m (15 lb ft)

(11) Tighten the locking nut to the approximate torque. ... 21 N·m (15 lb ft)

Margin pressure ... 1400 ± 100 kPa (200 ± 15 psi)

Pressure cutoff ... 14500 ± 350 kPa (2100 ± 50 psi)

Bench Test

Note: Connect the load sense port to the pump discharge port before testing. The pressure at the load sense port will be equal to the discharge pressure.

Note: The pump output is for a new pump that is using SAE 10 at approximate temperature of 50 °C (125 °F).

Pump at 690 kPa (100 psi) discharge pressure.

Output ... 55 L/min (14.5 US gpm)

Pump speed ... 2000 rpm

Pump at 6900 kPa (1000 psi) discharge pressure.

Output ... 53 L/min (14 US gpm)

Pump speed ... 2000 rpm

Machine Test

Note: Disconnect the solenoid for the demand fan before testing. The pressure at the load sense port will be equal to the discharge pressure.

Note: The pump output is for a new pump that is using SAE 10 at approximate temperature of 50 °C (125 °F).

Fan speed ... 1215 ± 25 rpm

Pump output ... 44 L/min (11.6 US gpm)

Discharge pressure ... 14500 kPa (2100 psi)

Pump speed ... 1660 rpm

Engine speed ... 1660 rpm