Hitachi 222104 Service, Intake Valve, Relieve the pressure, Air Motor, Displacement Pump

Service

NOTE: Clean and inspect all parts for wear or damage when disassembled. Replace parts as needed. Repair Kit 247431 is available. For the best results, use all the parts in the kit. Parts included in the kit are marked with an asterisk in the text, figures, Parts Drawing, and Parts List.

Intake Valve

See the Parts Drawing on page 13.

1.Relieve the pressure.

WARNING

To reduce the risk of serious injury whenever you are instructed to relieve pressure, always follow the Pressure Relief Procedure on page 8.

2.Unscrew the valve housing (21). Remove the o-ring (22*), ball (23), and retainer (20).

3.Inspect the parts for wear or damage. If the ball is nicked, replace it. Apply liquid sealant to the male threads, and reassemble.

Air Motor

See Fig. 3.

1.Relieve the pressure.

WARNING

To reduce the risk of serious injury whenever you are instructed to relieve pressure, always follow the Pressure Relief Procedure on page 8.

2.Remove the air hose and fluid hoses.

3.Place the air motor base (5) in a vise.

WARNING

To reduce the risk of injury from trapped air pres- sure when servicing the air motor, always remove air cap (2) from air cylinder (4) before removing air cylinder from base (5).

4.Remove the air cap (2). Gently pry the coils of the spring (17) to remove the spring. Check the spring for wear or damage, and replace as needed.

5.Use a strap wrench to unscrew the air cylinder (4) from the base (5).

6.Unscrew the air piston assembly (15) from the piston rod (10). Use pliers on the air exhaust plate (15c*) and a wrench on the piston rod. See the Piston Detail in Fig. 3.

10 307906

NOTE: Old, cured thread sealant on the piston rod threads makes it necessary that you use tools to remove the air piston assembly from the piston rod. Do not use these tools when you screw the air piston assembly onto the piston rod.

7.Disassemble the air piston assembly (15). See the Piston Detail in Fig. 3. Clean all parts, and inspect them for wear or damage. If any valve plate spacers are damaged, replace all three in order to maintain the correct clearance between the valve plates and seals.

8.Check the spring (8) for wear or damage, and replace as needed.

9.Apply sealant, such as LoctiteR green, to the threads of the screws. Assemble the parts as shown in the Piston Detail in Fig. 3. Torque the screws to 10 to 14 in-lb (1.3 to 1.6 N-m).

Displacement Pump

See Fig. 3, and see the Parts Drawing on page 13.

WARNING

Do not cycle the pump with any parts disassemb- led. See the Moving Parts Hazard on page 4.

1.Use a strap wrench on the fluid cylinder (24) to unscrew it from the motor base (5). Pull down on the piston rod (10) until you have access to the fluid piston assembly (19).

2.Stand the fluid piston assembly (19) in a vise, and remove the piston rod (10).

3.Unscrew the fluid piston (19) from the piston rod (10), and be careful not to drop the ball (18). Remove the piston rod the rest of the way from the base.

4.Remove the shaft seal (16*), wiper ring (11*), and the gasket (9*) from the top of the motor base (5).

5.Reach inside the opening of the air motor base (5) to remove the o-ring (26*). Carefully remove the wiper ring (11*) and the seal (12*) from the motor base.

6.Carefully inspect the smooth inner surface of the fluid cylinder (24) for scoring or irregular surfaces. Such damage causes premature packing wear and leaking, so replace the part if needed.

7.Lubricate and install the new shaft seal (16*), wiper ring (11*), and gasket (9*), seal (12*), wiper ring (11*), and o-ring (26*) into the base.

8.Lubricate the new seal (19b*), and install it on the fluid piston (19c).

9.Install washer (19a) onto fluid piston (19c).