HARNESS AS-REAR 2511302 - Caterpillar

Image1.4.1
5. Measure the length L of the adjust screw protruding beyond the gland nut, as shown in Image 1.5.1
Image 1.5.1 - Cutoff Pressure Adjust Screw Length L
Image1.5.1
6. Place the control valve vertically in a vice, with the cutoff adjust screw pointing up, and remove the complete cutoff adjust screw assembly by loosening the gland nut using a 17 mm box wrench.
7. Install the new cutoff adjuster kit 315-1525 by putting Loctite 603 on the thread of gland nut and tightening it to 25 N.m (18 ft.lbs). While tightening the gland nut, look through port T to ensure that the tip of the adjust screw properly engages the spring retainer. The tip of the adjust screw should be completely seated in the bottom of the spring retainer.
8. Loosen the locknut with a 10 mm box wrench and turn the adjust screw with a 2.5 mm Allen wrench until the screw length protruding from the gland nut matches to length L measured on the old cutoff adjust screw. Then tighten the locknut to 10.4 N.m (7.5 ft.lbs).
: Adjust screw length L should never be shorter than 10.5 mm. Under 10.5 mm, the o-ring on the adjust screw will start to protrude into passage A (see Image 1.8.1).
With the adjust screw at a length of 10.5 mm, the cutoff pressure will be around 30000 kPa (4351 psi).
Image 1.8.1
(1) O-Ring
(2) Passage A
Image1.8.1
9. Refer to D8T or D9T Service Manual Disassembly and Assembly (D8T-RENR7480, D9T-RENR7470), section "Piston Pump (Hydraulic Fan) - Assemble", to install the rebuilt control valve on the pump, using 3 o-ring seals 9X-7680.
10. Adjust the fan pump cutoff and standby pressures to the new specifications shown in Image 1.10.1 using the D8T or D9T Service Manual Testing and Adjusting (D8T-RENR7527, D9T-RENR7532) sections "Test Procedure (Maximum Mechanical High Pressure)", "Adjustment Procedure (Maximum Mechanical High Pressure)", "Test Procedure (Minimum Pump Pressure)" and "Adjustment Procedure (Minimum Pump Pressure)".
: Verify that a fan with 26? blade pitch has been installed on the machine according to service letters PI31275 or PI31342 before adjusting cutoff pressure to the new specifications. The fan part number is stamped on front side of a blade near the tip.
: The cutoff pressure adjust screw is VERY sensitive. It has a 15000 kPa per turn ratio (2175 psi/turn). If the cutoff pressure reaches 30000 kPa (4351 psi), the adjust screw o-ring seal will protrude into passage A and it could get cut, leading to contamination and incorrect valve operation.
The standby adjust screw has a 1600 kPa per turn ratio (232 psi/turn).
Image 1.10.1
Image1.10.1