Overhaul
Steering Gearbox Overhaul
Special Tools Required
^ Cylinder end seal remover attachment 07NAD-SR3020A
^ Valve seal ring sizing tool 07NAG-SR3090A
^ Ball joint boot clip guide 07974-SA50800
^ Sleeve seal ring sizing tool 07974-SA5020A or 07974-SA50200
^ Attachment, 32 x 35 mm 07746-0010100
^ Attachment, 24 x 26 mm 07746-0010700
^ Driver 07749-0010000
^ Piston seal ring guide 07HAG-SF10100
^ Piston seal ring sizing tool 07HAG-SF1020A or 07HAG-SF10200
^ Cylinder end seal slider 07ZAG-S5A0300
^ Pincers Oetiker 1098 or equivalent, commercially available
NOTE: Refer to the Exploded View as needed during this procedure.
Removal
1. Remove the steering gearbox.
Disassembly
2. Remove the boot bands (A) and tie-rod clips (B). Pull the boot away from the ends of the steering gearbox.
3. Unbend the lock washers (A).
4. Hold the flat surface sections (A) of the steering rack with a wrench (B), and unscrew both rack ends (C) with another wrench (D). Be careful not to damage the rack surface with the wrench.
5. Remove the lock washer (E) and rubber stop (F).
6. Loosen the locknut (A), then remove the rack guide screw (B).
7. Remove the spring (C) and the rack guide (D) from the gearbox housing.
8. Remove the cylinder lines from the gearbox.
NOTE: Use a second wrench when loosening the cylinder lines to avoid damage to the fittings on the steering gearbox. Do not loosen the A and B connectors.
9. Drain the fluid from the cylinder fittings by slowly moving the steering rack back and forth.
10. Remove the stepping valve motor (A), then remove the connector holder mounting bolt (B) on the valve housing.
11. Remove the end plug (A) from the gearbox housing, then remove the nut (B) from the pinion shaft end.
12. Remove the flange bolt, the valve body unit (A), and gasket (B) from the gearbox. Check that the valve turns smoothly by turning the pinion shaft. If any play or roughness is felt, replace the valve body unit with a new part if necessary. Do not try to disassemble the valve body unit.
13. Slide the steering rack all the way to the left.
14. Drill a 3 mm (0.12 in.) diameter hole about 2.5 - 3.0 mm (0.10 - 0.12 in.) in depth in the staked point (A) on the cylinder. Do not allow metal shavings to enter the cylinder housing. After removing the cylinder end (B), remove any burrs at the staked point.
15. Hold the gearbox housing using a C-clamp (commercially available) (A) and the wooden blocks (B) as shown. Do not clamp the cylinder part of the gearbox housing in the vise. Then remove the cylinder end (C).
16. Install a commercially available bearing separator (A) in the gearbox housing as shown.
17. Place an appropriate size extension (B) on the steering rack (C).
18. Set the steering gearbox in a press so the gearbox housing side points upward, then press the cylinder end seal (D) and steering rack out of the gearbox. Hold the steering rack to keep it from falling when pressed clear. Be careful not to damage the inner surface of the cylinder housing with the tool.
19. Install the cylinder end seal remover attachment (A) so it will fit through the rack guide hole of the gearbox housing. Insert a 24" long, 3/8" drive extension (B), and install it on the Cylinder end seal remover attachment. Make sure the cylinder end seal remover attachment is securely positioned on the backup ring edges. Be careful not to damage the inner surface of the cylinder with the Cylinder end seal remover attachment.
20. Place the steering gearbox in a press, then remove the cylinder end seal (A) and backup ring (B) from the gearbox by pressing on the 24" long, 3/8" drive extension.
Note these items when pressing the cylinder end seal:
^ Keep the tool straight to avoid damaging the cylinder wall. Check the tool angle, and correct it if necessary, when removing the cylinder end seal.
^ Use a press to remove the cylinder end seal. Do not try to remove the seal by striking the tool; striking the tool could break the backup ring, and the cylinder end seal would remain in the gearbox.
21. Carefully pry the piston seal ring (A) and O-ring (B) off the rack piston. Be careful not to damage the inside of the seal ring groove and piston edges when removing the seal ring.
22. Before removing the valve housing (A), apply vinyl tape (B) to the splines on the pinion shaft.
23. Separate the valve housing (A) from the pinion shaft/valve (B) using a press, then remove the pinion oil seal (C).
24. With your finger, check the inner wall of the valve housing where the seal ring slides. If there is a step in the wall, the housing is worn. Replace it.
NOTE: There may be sliding marks from the seal ring on the wall of the valve housing. Replace the valve housing only if the wall is stepped.
25. Check for wear, burrs, and other damage to the edges of the grooves in the sleeve.
NOTE: The pinion shaft and sleeve are a precision matched set. If either the pinion shaft or sleeve must be replaced, replace both parts as a set.
26. Remove the snap ring (A) and sleeve (B) from the pinion shaft.
27. Using a cutter or an equivalent tool, cut and remove the four seal rings from the sleeve. Be careful not to damage the edges of the sleeve grooves and outer surface when removing the seal rings.
28. Remove the O-ring (A). Be careful not to damage the edges of the pinion shaft groove and outer surface when removing the O-ring.
29. Press the valve oil seal (A) and ball bearing (B) out of the valve housing using a hydraulic press, driver and attachment, 24 x 26 mm.
30. Clean the disassembled parts with solvent, and dry them with compressed air. Do not dip rubber parts in the solvent.
Reassembly
31. Apply power steering fluid to the surface of the ball joint boot clip guide. Slip two new seal rings (A) over the ball joint boot clip guide from the smaller diameter end, and expand them. Install only two rings at a time from each end of the pinion shaft sleeve (B).
Note these items when installing the seal ring:
^ Do not over-expand the seal ring. Install the resin seal rings with care so as not to damage them. After installation, make sure you contract the seal rings using the sleeve seal ring sizing tool.
^ There are two types of sleeve seal rings: black and brown. Do not mix the different types of rings as they are not compatible.
32. Align the ball joint boot clip guide with each groove in the sleeve, and slide a sleeve seal ring into each groove. After installation, compress the seal rings with your fingers temporarily.
33. Apply power steering fluid to the seal rings on the sleeve, and to the entire inside surface of the sleeve seal ring sizing tool, then slowly insert the sleeve into the sleeve seal ring sizing tool.
34. Move the sleeve back and forth several times to make the seal rings snugly fit in the sleeve. Make sure the seal rings are not twisted.
35. Apply power steering fluid to the surface of the pinion shaft (A). Slide the sleeve (B) onto the pinion shaft by aligning the locating pin (C) on the inside of the sleeve with the cutout (D) in the shaft. Then install the new snap ring (E) securely in the pinion shaft groove. Be careful not to damage the valve seal ring when inserting the sleeve.
36. Apply power steering fluid to the seal ring lip of the new valve oil seal (A), then install the seal in the valve housing (B) using a hydraulic press, driver and attachment, 32 x 35 mm. Install the seal with its grooved side facing the tool.
37. Press the ball bearing (C) into the valve housing with a hydraulic press and special tools.
38. Apply vinyl tape (A) to the pinion shaft, then coat the vinyl tape with power steering fluid.
39. Insert the pinion shaft into the valve housing (B). Be careful not to damage the valve seal rings (C) and valve oil seal sealing lip (D).
40. Install the pinion oil seal (E) onto the pinion shaft with its grooved side (F).
41. Remove the vinyl tape from the pinion shaft, then remove any residue from the tape adhesive.
42. Press the pinion shaft/sleeve into the valve housing with a hydraulic press. Check that the pinion shaft/sleeve turns smoothly by hand after installing it.
43. Coat the piston seal ring guide with power steering fluid, then slide it onto the rack, big end first.
44. Position the new O-ring (A) and new piston seal ring (B) on the piston seal ring guide, then slide them down toward the big end of the tool.
Note these items during reassembly:
^ Do not over expand the resin seal rings. Install the resin seal rings with care so as not to damage them. After installation, make sure you contract the seal ring using the piston seal ring sizing tool.
^ Replace the piston's O-ring and seal ring as a set.
45. Pull the O-ring off into the piston groove, then pull the piston seal ring off into the piston groove on top of the O-ring.
46. Coat the piston seal ring (A) and the inside of the piston seal ring sizing tool with power steering fluid, then carefully slide the tool onto the rack and over the piston seal ring.
47. Move the piston seal ring sizing tool back and forth several times to make sure the piston seal ring fits snugly in the piston.
48. Coat the sliding surface of the cylinder end seal slider (A) and new cylinder end seal (B) with power steering fluid. Place the seal on the cylinder end seal slider with its grooved side (C) facing opposite the cylinder end seal slider.
49. Coat the surface of the steering rack (A) with power steering fluid.
50. Install the cylinder end seal (B) onto the steering rack with its grooved side (C) toward the piston (D).
51. Separate the cylinder end seal from the special tool, then remove the special tool.
52. Install the new backup ring (A) on the steering rack, then place the backup ring and cylinder end seal (B) against the piston (C).
53. Apply multipurpose grease to the steering rack teeth, then insert the steering rack into the gearbox housing. Be careful not to damage the inner surface of the cylinder wall with the rack edges.
54. Insert an appropriate size deep socket wrench (A) onto the steering rack as shown.
55. Install the cylinder end seal (B) into the bottom of the cylinder by pressing on the tool with a press. Do not push on the tool with excessive force as it may damage the cylinder end seal.
56. Remove the tool, and center the steering rack.
57. Coat the sliding surface of the cylinder end seal slider (A) and new cylinder end seal (B) with power steering fluid. Place the seal on the cylinder end seal slider with its grooved side (C) facing opposite the cylinder end seal slider.
58. Coat the inside surface of the cylinder end seal slider and steering rack with power steering fluid, then install the cylinder end seal (A) onto the steering rack with its grooved side toward the cylinder.
59. Separate the cylinder end seal from the cylinder end seal slider, then remove the cylinder end seal slider.
60. Push in the cylinder end seal with your finger. Be careful not to damage the face of the seal with the threads and burrs at the staked position of the cylinder housing.
61. Hold the gearbox housing using a C-clamp (commercially available) (A) and the wooden blocks (B). Do not clamp the cylinder part of the gearbox housing in the vise.
62. Coat the inside surface of the cylinder end (A) with power steering fluid, then install the cylinder end by screwing it into the cylinder (B). Tighten the cylinder end to the specified torque.
63. Stake (C) the point of the cylinder shown (opposite from where the stake was removed during disassembly).
64. Apply multipurpose grease to the bearing (A) in the gearbox housing, and install the valve body unit (B) and new gasket (C) by engaging the gears. Note the valve body unit installation position (direction of line connections). Then loosely install the two flange bolts.
65. Install the new self-locking nut (A) onto the pinion shaft end, and tighten to the specified torque.
66. Tighten the flange bolts to the specified torque.
67. Apply new sealant (Loctite 565) all the way around the threads on the end plug (B), install the end plug onto the gearbox housing, and tighten it to the specified torque.
68. After tightening, use a drift to stake (A) the end plug shoulder against the gearbox housing.
69. Install the stepping valve motor (A), with coat the new O-ring (B) with multipurpose grease.
70. Tighten the flange bolts (C) to the specified torque.
71. Before installing the cylinder lines, coat the new O-rings with power steering fluid, then install the lines.
Note these items during reassembly:
^ Thoroughly clean the joints of the cylinder lines. The joints must be free of foreign material.
^ Install the cylinder lines by tightening the flare nuts by hand first, then tighten the flare nuts to the specified torque.
NOTE: Use a second wrench when tightening the cylinder lines to avoid damaging to the fittings on the steering gearbox.
72. Apply multipurpose grease to the sliding surface of the rack guide (A), and install it onto the gearbox housing.
73. Apply new sealant (Three Bond 1141) all the way around the first three threads of the rack guide screw (B), then install the spring (C), rack guide screw, and locknut (D).
74. Adjust the rack guide screw. After adjusting, check that the rack moves smoothly by sliding it right and left.
75. Install the new rubber stop (A) and lock washer (B). Align the lock washer tabs (C) with the slots (D). Install the rack end (E) while holding the lock washer in place. Repeat this step for the other side of the rack.
76. Hold the flat surface sections of the steering rack with a wrench, and tighten both rack ends. Be careful not to damage the rack surface with the wrench.
77. Bend the lock washer (A) back against the flat spots on the rack end joint housing.
78. Apply multipurpose grease to the circumference of the rack end joint housing (A).
79. Apply a light coat of silicone grease to the boot grooves (B) on the rack ends.
80. Center the steering rack within its stroke.
81. Clean off any grease or contamination from the boot installation grooves (A) and around the gearbox housing. Install the boots (B) on the rack ends with the tie-rod clips (C), and fit the boot end in the installation grooves in the housing properly.
82. After installing the boots, wipe any grease off the threaded section (D) of the rack end.
83. Install the new boot bands by aligning the tabs (A) with the holes (B) of the band.
84. Close the ear portion (A) of the band (B) with commercially available pincers, Oetiker 1098 or equivalent (C).
85. Slide the rack right and left to be certain that the boots are not deformed or twisted.