Hitachi SERIES F manual Service, Disconnecting the Displacement Pump, Intake Valve Fig, Piston Fig

Service

Notes

DRepair Kit 223–439 is available to service the pump. For the best results, use all the kit parts. Parts included in the kit are marked with an asterisk in the text, for example (15*).

DIf possible, have all the necessary replacement parts available before you begin the repair, to reduce down time.

DWhen replacing the displacement rod (36) or the cylinder (38), always replace all of the pump pack- ings, seals, and glands, to ensure proper sealing.

Disconnecting the Displacement Pump

WARNING

To reduce the risk of serious injury whenever you are instructed to relieve pressure, always follow the Pressure Relief Procedure on page 5.

1.Solvent flush the pump if possible. Then, relieve the pressure.

2.Disconnect the hoses from the pump. Remove the pump from its mounting and clamp it in a vise.

3.Disconnect the displacement pump from the motor as explained in your separate pump manual.

Intake Valve (Fig. 1)

1.Remove the hex nuts (13) and washers (14) from the tie rods (32). Unscrew the tie rods from the intake valve (42). Remove the intake valve from the pump.

2.Disassemble the intake valve. Take note of which set of holes the ball stop pin (28) is in.

3.Clean all parts thoroughly, and inspect them for wear or damage. Replace parts as needed.

4.Reassemble the valve. Place the ball stop pin (28) in the same holes from which it was removed. If you want to change the fluid flow through the pump, place the pin in a different set of holes. Refer to Check Valve Adjustment.

5.If no further service is needed, reinstall the intake valve on the pump. Torque the hex nuts (13) evenly to 50–60 ft-lb (68–81 NSm), using a criss- cross tightening pattern.

Piston (Fig. 1)

1.Remove the intake valve as explained in Intake Valve.

2.Pull the cylinder (38) down, off the piston assem- bly.

3.Unscrew the piston retainer screws (25). Remove the piston parts from the displacement rod (36).

4.Clean all parts thoroughly, and inspect them for wear or damage. Replace parts as needed.

5.Place the gasket (49) and ball (16) on the piston retainer (43). Install these parts in the displace- ment rod.

NOTE: The piston retainer (43) must not obstruct the ports in the displacement rod (36).

6.Install one cup packing (31*) on the displacement rod (36). Be sure the lips of the packing face up.

7.Install the packing spacer (30). Position one cup packing (31*) on the displacement rod so the lips of the packing face down.

8.Install the piston guide (35). Install the four screws

(25)through the piston assembly and screw them into the displacement rod (36). Torque the screws evenly to 30–40 ft-lb (41–54 NSm), using a criss- cross tightening pattern.

9.If no further service is needed, go to Throat Pack- ings. If no further service is needed, slide the cylinder (38) and gaskets (24*) over the piston assembly. Install the intake valve. Torque the nuts

(13)evenly to 50–60 ft-lb (68–81 NSm).

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