HOSE AS 3785730 - Caterpillar

--------------- END SUPPLEMENT ---------------Description of Change: The vibratory pump now used on the CS-573 and CS-583 single drum compactors includes updated components to improve service life. A new valve plate is used to minimize swashplate fatigue caused by pressure pulses from the rotary group. The shaft bearing is now a straight roller type for increased service life. The tapered shaft has improved metallurgical properties in the threaded area to increase strength. The swashplate maximum angle is now controlled with an internal stop. The former stops that were externally adjustable are no longer used.
Adaptable To: The new 112-9562 Pump Group replaces the former 1G-8239, 105-4847, and 107-9356 Pump Groups, which are canceled. The new pump is effective with CS-573 (8PK70) and CS-583 (8YJ142, 1EL184) Vibratory Compactors. The new pump is also adaptable to CS-573 (8PK1-69) and CS-583 (8YJ1-141, 1EL1-183) Vibratory Compactors.
Illustration 1. Vibratory pump. See chart for item descriptions.When rebuilding the former pumps, use the new parts listed in the chart and Illustration 1. Also, use the following procedure when disassembling and assembling the servo assembly. This procedure is not contained in the Service Manual.
Servo Piston Disassembly
All hydraulic hoses and pump adapters should be capped and plugged to minimize hydraulic oil leakage, and to prevent possible contamination of the vibratory closed loop circuit. Pump disassembly and reassembly should be performed in a clean environment to minimize contamination of pump components. Replace all seals and gaskets when assembling the pump.
Illustration 2. Servo piston. (A) Centering Screw. (B) Cover. (C) Half nut. (D) Nut. (E) Retaining ring. (F) Outer spring guide. (G) Servo spring. (H) Servo stop. (J) Inner spring guide.1. Unscrew the piston assembly from cover (B).2. Hold centering screw (A) from turning and tighten nut (D) (using a 9/16" wrench) to compress servo piston spring (G), and to relieve pressure on retaining ring (E).3. Remove the retaining ring from the piston using two screw drivers. Slide the centering spring assembly out of the servo piston.4. Remove half nut (C) and nut (D) from the centering screw. Remove outer spring guide (F), servo stop sleeve (H), servo spring (G), and inner spring guide (J) from the centering screw. Servo stop sleeve (H) serves as a maximum displacement stop.Servo Piston Assembly
1. Install inner spring guide (J), servo spring (G), servo stop sleeve (H), and outer spring guide (F) onto centering screw (A). Install nut (D) and half nut (C) onto the centering screw.2. Hold the centering screw from turning and tighten nut (D) to compress the servo piston spring.3. Slide the centering spring assembly into the servo piston. Install retaining ring (E) into the servo piston to retain the spring assembly. If the retaining ring cannot be installed, compress the spring assembly further by tightening nut (D) on the centering screw.4. Loosen nut (D) on the centering screw to seat the retaining ring, then tighten the nut until all axial looseness between centering screw (A) and the servo piston is eliminated. If the nut is too tight, the spring assembly will