797F and 797F XQ Off-Highway Truck Steering System Caterpillar

Illustration 1	g01948221
Top view

Rotation ... Counterclockwise when you view the pump from the drive end.

Maximum displacement per revolution for front pump ... 190.0 cc (11.6 cubic inch)

Maximum displacement per revolution for rear pump ... 190.0 cc (11.6 cubic inch)

Setting for pressure override valve for front pump ... 28200 ± 500 kPa (4090 ± 73 psi)

Setting for pressure override valve for rear pump ... 24500 ± 500 kPa (3553 ± 73 psi)

Bench test requirements with SAE 10W oil at 82 ± 4 °C (180 ± 7 °F) before the test is performed.

Test at Full Speed

Output ... 336.0 L/min (88.8 US gpm)

Test pressure ... 690 kPa (100 psi)

Test speed of the pump ... 1900

Test speed of the engine ... 1800

Output ... 334.0 L/min (88.2 US gpm)

Test pressure ... 6900 kPa (1001 psi)

Test speed of the pump ... 1900

Test speed of the engine ... 1800

Test at Half Speed

Output ... 166.0 L/min (43.9 US gpm)

Test pressure ... 690 kPa (100 psi)

Test speed of the pump ... 950

Test speed of the engine ... 900

Output ... 163.0 L/min (43.1 US gpm)

Test pressure ... 6900 kPa (1001 psi)

Test speed of the pump ... 950

Test speed of the engine ... 900

(1) Torque for eight bolts ... 620 N·m (457 lb ft)

Illustration 2	g01958079
Section A-A (2) Pump control valve group (3) Pump rotating group (4) Pump rotating group (5) Pump head group

(6) Torque for eight plug assemblies ... 10 N·m (89 lb in)

Illustration 3	g01958082
Detail C (7) Piston

(8) Use anyone of the following rod to obtain the dimension (E):

Dimension (E) ... 90 degrees

Length of the 145-3793 Rod ... 128.55 mm (5.061 inch)

Length of the 145-3794 Rod ... 127.95 mm (5.037 inch)

Length of the 179-6933 Rod ... 128.4 mm (5.06 inch)

Length of the 145-3792 Rod ... 128.25 mm (5.049 inch)

Illustration 4	g01958087
Pump head group

(9) Torque for two orifice plugs ... 6.5 N·m (57.5 lb in)

(10) Torque for two orifices ... 6.5 N·m (57.5 lb in)

215-6758 Pump Control Valve Gp (2)

Illustration 5	g01958090

(11) Torque for the nut ... 22 N·m (195 lb in)

(12) Torque for the plug ... 60 ± 4 N·m (44 ± 3 lb ft)

(13) 117-7522 Spring

Free length ... 16.75 mm (0.660 inch)

Outside diameter ... 14.7 mm (0.58 inch)

(14) 170-9822 Spring

Free length ... 12.2 mm (0.48 inch)

Outside diameter ... 14.9 mm (0.59 inch)

(15) 170-9821 Spring

Free length ... 47.0 mm (1.85 inch)

Outside diameter ... 21.4 mm (0.84 inch)

253-1551 Pump Rotating Gp (3)

Illustration 6	g01958092

(16) 179-6916 Spring

Free length ... 11.17 mm (0.440 inch)

Outside diameter ... 5.80 mm (0.228 inch)

(H) Dimension ... 145.85 to 146.10 mm (5.742 to 5.752 inch)

(17) As required, use the following shims in order to achieve the dimension (H). Use three 8.400 ± 0.010 mm (0.3307 ± 0.0004 inch) long pins in place of springs (16) to determine the shims that are required in order to achieve dimension (H).

179-6915 Shim

Thickness of the shim ... 0.50 mm (0.020 inch)

179-6914 Shim

Thickness of the shim ... 0.75 mm (0.030 inch)

(18) Torque for four bolts ... 10.4 N·m (92.0 lb in)

Note: Apply 4C-4030 Thread Lock Compound to the threads of bolts (19).

(19) Torque for four bolts ... 18 N·m (159 lb in)

253-1552 Pump Rotating Gp (4)

Illustration 7	g01958097

(20) 179-6916 Spring

Free length ... 11.17 mm (0.440 inch)

Outside diameter ... 5.80 mm (0.228 inch)

(J) Dimension ... 145.85 to 146.10 mm (5.742 to 5.752 inch)

(21) As required, use the following shims in order to achieve the dimension (J). Use 8.400 ± 0.010 mm (0.3307 ± 0.0004 inch) long pins in place of springs (20) to determine the shims that are required in order to achieve dimension (J).

179-6915 Shim

Thickness of the shim ... 0.50 mm (0.020 inch)

179-6914 Shim

Thickness of the shim ... 0.75 mm (0.030 inch)

Note: Apply 4C-4030 Thread Lock Compound to the threads of bolts (22).

(22) Torque for four bolts ... 18 N·m (159 lb in)