Usage:
Plug the four port holes and clean the exterior of the unit thoroughly. Then remove the plugs.
1. Remove Dirt Seal (2) and discard.
2. To prevent possible distortion of damage to unit if placed directly in vise, the following procedure should be used. Insert "o" ring tube fitting, with tube nut or fitting cap attached, into one of the four threaded ports in the housing. Clamp the fitting in a vise in a manner which will locate the seven end cover bolts in an upright position. (See figure HGA-7).
Figure HGA-7
3. Unscrew the seven special bolts (39) from the end cover (38). Note: Special care should be used in the following steps to insure protection of the ground and lapped faces of the components. Avoid scratching or nicking of finished surfaces.
4. Remove end cover (38) by bumping it sideways with a soft hammer to loosen it from the rotor seal (36) and seal retainer (35), and lift from unit. Caution: The washer (37) and commutator (34) may adhere to the end cover, and may be removed with the end cover. Do not attempt to remove pin because pin is press fit in the plate and is non-serviceable. (See Figure HGA-8).
5. Remove the rotor seal (36) and seal retainer (35) by bumping the retainer sideways with a soft hammer to loosen it from the valve body and lift off the rotor seal and seal retainer. Discard rotor seal.
6. If the wear washer (37) and commutator (34) were not removed with the end cover (38), remove these parts from the HGA unit.
Figure HGA-8
7. Remove the commutator ring (33) from the manifold (32), by a sliding and lifting motion. Care should be used in the handling of this fragile component.
8. Remove the manifold (32) from the rotor set (31) by sliding and lifting motion.
9. Remove the rotor set (31), spacer (29) and drive link (30) as an assembly by grasping the spacer and removing the assembly with a sliding and lifting motion. (See figure HGA-9).
Figure HGA-9
10. Separate drive link (30) by sliding the rotor set (31) on the spacer (29), allowing the drive link teeth to clear the spacer hole. Remove drive link and separate rotor set from spacer. Use extreme caution to keep vanes (31D) and springs (31C) from falling out. When handling the rotor set, pressure should be applied to the rotor (31B) by gripping the rotor set between the fingers and urging the rotor into contact with the stator (31A). (See figure HGA-10)
Carefully protect against damage to side faces.
NOTE: The rotor (31B) and the stator (31A) must be kept in a matched set.
Figure HGA-10
11. Reverse the HGA unit in the vise to place the input shaft (16) in a vertical position. Using a prick or center punch, mark the upper cover flange (7) in relation to a similar mark placed on the port face of the housing (25) to facilitate reassembly. (See figure HGA-11).
Figure HGA-11
12. Remove the four special cap screws (6) by using a 5/16-12 point socket.
13. Grasp the input shaft (16) and with a smooth upward motion, remove the input shaft (16), upper cover (7) and spool (22) assembly from the housing (25). Note: Avoid applying side forces to the spool which would cause binding of the closely fitted assembly. Never use excessive force to remove the spool from the housing.
14. Remove and discard "o" ring.
15. Remove the upper cover (7) with shaft seal package (Items 3 thru 5) intact. Remove spacer item (15).
16. Remove shims (9) from either upper cover (7) cavity or from face of thrust washer (11). Count and record the number of shims to aid in reassembly of unit.
17. Remove retaining ring (3), using proper snap ring pliers. Remove and discard backup washer (4). Remove and discard seal (5). Note: Seal item (5) can be removed by plugging three of the four ports in the Hydraguide unit, then pressurize the other port with air pressure to force the two ports out.
18. Remove the retaining ring (10), thrust washer (11), thrust bearing (12), thrust washer (13) and spring washer (14) from input shaft (16).
19. Remove the needle roller (17) by using a pin punch of .120 max. diameter for a minimum of .625 length. The input shaft (16) should be placed on a block of wood (to avoid shaft damage) and the needle pin removed by impact, using light hammer blows. (See figure HGA-12)
Figure HGA-12
20. Remove the torsion bar (20) and spacer (19) by inverting the spool assembly and allowing the parts to fall free. Do not remove pin from torsion bar. (See figure HGA-13).
Figure HGA-13
21. Remove the drive ring (18) by placing the end of the spool (22) on a table surface. Rotate the input shaft (16) to extremes of travel until the drive ring falls free. (See figure HGA-14).
Figure HGA-14
22. With the spool assembly in the same position as the step above, rotate the input shaft (16) in a clockwise direction until the actuator ball (23) disengages from the helical groove in the input shaft. Lift out input shaft. Caution: The actuator ball may fall free and care should be used to not lose it.
23. Do not remove the ball retainer spring (24) unless replacement is required. If necessary to remove this spring, grasp the flattened end of retainer spring with pliers and lift the flattened end over the shoulder on the spool (22). Continue with a pulling motion, to progressively remove the retainer spring.
A screwdriver may be used to assist in the prying of the spring over the shoulder of the spool. Care must be used to avoid scratching or nicking of the spool outside diameter and control edges.
(The following standard procedure is optional).
24. Return to the housing (25) which is mounted in the vise. Remove the plug and roll pin assembly (28). A steel ball is captivated by the plug and roll pin assembly. Care must be used to avoid the loss of the ball. Remove ball by shaking after housing is removed from the vise. Discard "O" ring (27).
This completes the disassembly of the HGA unit.