Disassembly and Assembly
DISASSEMBLYFig. 1 Exploded View Of Manual Steering Gear Assembly:
1. Drain lubricant from gearbox through filler plug hole, Fig. 1.
2. Clamp steering gear in a suitable vise.
3. Remove adjust screw locknut, turn adjust screw counterclockwise removing sector gear and ball nut rack preload. Remove top cover bolts.
Fig. 2 Gearbox Top Cover Removal:
4. Hold the top cover stationary while turning the adjust screw clockwise to raise and free the cover, then remove the cover, Fig. 2.
Fig. 3 Selector Shaft Removal:
5. Bring worm shaft into straight ahead position and remove top cover and sector shaft from the gearbox, Fig. 3. Hold the sector shaft in straight ahead position when removing from gearbox. Do not drive the sector shaft out with a hammer or other impact tools.
Fig. 4 End Cover Locknut Removal:
6. Using locknut removal tool No. J-29753, or equivalent, loosen the locknut securing the end cover, Fig. 4.
Fig. 5 End Cover Removal:
7. Using removal tool No. J-7624, or equivalent, remove end cover, Fig. 5.
Fig. 6 Ball Screw & Nut Assembly Replacement:
8. Remove the ball screw and nut assembly from the gearbox, Fig. 6. Remove the lower bearing. Keep worm and ball nut assembly in horizontal position. Avoid holding vertically, as ball nut will fall onto end of worm gear and cause damage to ball tubes.
ASSEMBLY
1. Inspect and replace seals if necessary.
2. Install lower bearing and ball screw and nut assembly into gearbox, keeping it horizontal. Apply gear oil to the bearings, Fig. 6.
Fig. 7 Worm Shaft Bearing Preload Measurement:
3. Clean end cover and gearbox mating surfaces and fit new O-ring into the cover. Apply gear oil to oil seal and O-ring. Fit the cover over the worm shaft, being careful not to damage the seal (taping the worm shaft spline may help). Screw in the end cover, until torque required to rotate the worm shaft is 1.64-5.15 inch lbs., Fig. 7.
Fig. 8 End Cover Locknut Installation:
4. Install and tighten locknut to specifications, Fig. 8.
Fig. 9 Sector Shaft Endplay Measurement:
5. Install the adjust screw with adjusting shim into sector shaft T slot. Check that no clearance is provided between the adjust screw head and sector shaft and the adjust screw slides freely in the slot. If the adjust screw and sector shaft clearance is in excess of .004 inch, it must be adjusted by means of shims, Fig. 9. Shims are available in the following sizes: 0.0596-0.0604 inch, 0.060-0.0616 inch, 0.0620-0.0627 inch, 0.0631-0.0639 inch and 0.0643-0.0651 inch. When reassembling the adjusting shim, turn the face of the shim with chamfer on the inner edge to the adjust screw head. Apply grease to the T slot in the sector shaft, before reassembling the adjust screw.
Fig. 10 Sector Shaft Installation:
6. Apply grease to the bushing and oil seal in the gearbox. Install the sector shaft as shown in Fig. 10.
7. Apply a suitable sealing compound to gearbox top cover mounting surface and to thread holes. Install gasket in top cover.
8. Thread the adjust screw into top cover turning the screw counterclockwise until the top cover contacts the gearbox, continue turning for two or more turns and install the bolts and washers. Tighten bolts to specification.
9. Holding the relative parts in a straight ahead position, rotate the worm shaft with an inch-pound wrench. Adjustment of backlash is made by turning in the adjust screw, so that starting torque checked at straight ahead position is 4.3-8.7 inch lbs. Tighten adjust screw locknut.
10. Install pitman arm. Tighten bolts to specification.
11. Install coupling on the worm. Tighten bolts to specification.
12. Add 7 oz. of GL-5 lubricant to gearbox.