Steering Gearbox Overhaul

Exploded View


 

Special Tools Required
Cylinder end seal remover attachment (  07NAD-SR30200)
 

Driver, 27 mm (  07ZAF-S5A0100)
 
Valve seal ring sizing tool (  07NAG-SR30900)
 
Sleeve seal ring guide (  07YAG-S2X0100)
 
Sleeve seal ring sizing tool (  07ZAG-SA50100)
 
Attachment, 32 x 35 mm (  07746-0010100)
 
Driver (  07749-0010000)
 
Piston seal ring guide, 42 mm (  07ZAG-S7A0100)
 
Piston seal ring sizing tool, 42 mm (  07ZAG-S7A0200)
 
Locknut wrench (  07ZAA-S5A0100)
 
Driver handle (  07NAD-SR30101)
 
Cylinder end seal slider, 23 mm (  07974-6890801)
 
Valve seal ring guide (  07ZAG-S5A0200)
 
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 cylinder lines (A) and return line joint (B) from the gearbox.

 

3.Drain the fluid from the cylinder fittings by slowly moving the steering rack back and forth.

4.Unbend the lock washer (A).

 

5.Hold the bracket (A) with one wrench, and unscrew both rack ends (B) with another wrench. Remove the lock washers.

 

6.Remove the stop washer (A), the 12 mm flange bolts (B), O-rings (C), and bracket (D) from the steering gearbox.

 

7.Remove the boot guard (A) by removing the 8 mm flange bolt (B) on the rack end.

 

8.Remove the boot band (C) and clip (D). Pull the boot (E) away from the end of the steering gearbox. Remove the rack end plug (F).

9.Loosen the locknut (A), then remove the rack guide screw (B), spring (C), and rack guide (D) from the steering gearbox.

 

10.Remove the snap ring (A) and backup ring (B) from the cylinder housing.

 

11.Remove the valve body unit (A) from the steering gearbox. Remove the O-ring (B) and discard it.

 

12.Remove the two boot bands (B) from boot A. Compress boot A by hand, and apply vinyl tape (C) so the boots stay collapsed and pulled back.

 

13.Hold the gearbox housing using a C-clamp (commercially available) (A) and the wooden blocks (B) as shown. Do not clamp the cylinder housing or gearbox housing in the vise.

 

14.Install the special tool (A) on the lock screw (B), then loosen and remove the lock screw from inside of the gearbox housing (C).

 

15.Remove the special tool.

16.Pull on the cylinder to remove it from the gearbox housing. Remove boot A and the slider guide (B) from the cylinder.

 

17.Check the slider guide for damage and cracks. Use vernier calipers to measure the thickness of the slider guide. If the thickness is less than the service limit, replace the slider guide.

 

18.Remove and discard the stop ring (A) on the cylinder by expanding it with snap ring pliers. Remove and discard the lock screw (B).

 

19.Set the cylinder housing (A) in a press so the cylinder side points downward, then press the cylinder end seal (B) and steering rack (C) out of the cylinder. Hold the rack to keep it from falling when pressed clear.

 

20.Remove the cylinder end seal from the steering rack.

21.Insert the special tools into the cylinder.
Make sure the attachment (A) of the special tools is securely positioned on the bushing edges (B).

 

22.Place the cylinder in a press, then remove the cylinder end seal (C), backup ring (D), and bushing (B) from the cylinder by pressing on the special tool end.

Note the items when pressing the cylinder end seal:
  • Keep 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 would break the cylinder end seal, and the seal would remain in the cylinder.

23.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.

 

24.Before removing the valve housing (A), apply vinyl tape (B) to the splines on the pinion shaft.

 

25.Separate the valve housing from the pinion shaft/valve using a press.

26.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.

 

27.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.

 

28.Remove the snap ring (A) and sleeve (B) from the pinion shaft.

 

29.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 the outer surface when removing the seal rings.

 

30.Using a cutter or an equivalent tool, cut the valve seal ring (A) and O-ring (B) at the groove (C) in the pinion shaft. Remove the valve seal ring and O-ring. Be careful not to damage the edges of the pinion shaft groove and outer surface when removing the valve seal ring and O-ring.

 

31.Remove the valve oil seal (A) and wave washer (B) from the pinion shaft.

Note these items during disassembly:
  • Inspect the ball bearing (C) by rotating the outer race slowly. If there is any excessive play, replace the pinion shaft and sleeve as an assembly.
  • The pinion shaft and sleeve are a precise fit; do not intermix old and new pinion shafts and sleeves.

 

32.Press the valve oil seal (A) and roller bearing (B) out of the valve housing using a hydraulic press and special tool.

 

Reassembly


33.Apply vinyl tape (A) to the stepped portion of the pinion shaft, and coat the surface of the vinyl tape with the power steering fluid.

 

34.Install the wave washer (B). Coat the inside surface of the new valve oil seal (C) with power steering fluid, and install the seal with its grooved side facing opposite the bearing, then slide it over the pinion shaft, being careful not to damage its sealing lip (D). Remove the vinyl tape.

35.Install the special tool over the pinion, and coat the surface of the tool with the power steering fluid. Slip the new O-ring (A) and new valve seal ring (B) over the special tool, and expand them.

 

36.Fit the O-ring and in the groove of the pinion shaft. Then slide the valve seal ring over the shaft and in the groove on the pinion shaft.

37.Remove the special tool, and apply power steering fluid to the surface of the valve seal ring (A).

 

38.Apply power steering fluid to the inside of the special tool. Set the larger diameter end of the special tool over the valve seal ring, and move the special tool up and down several times to make the valve seal ring fit in the pinion shaft groove.

39.Remove the special tool, turn it over, slide the smaller diameter end over the valve seal ring. Move it up and down several times to make the valve seal ring fit snugly in the pinion shaft groove.

40.Apply power steering fluid to the surface of the special tool. Slip two new seal rings (A) over the special tool 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, be sure to contract the seal rings using the special tool (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.

 

41.Align the special tool 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.

42.Apply power steering fluid to the seal rings on the sleeve, and to the entire inside surface of the special tool, then slowly insert the sleeve into the special tool.

 

43.Move the sleeve back and forth several times to make the seal rings snugly fit in the sleeve. Be sure that the seal rings are not twisted.

44.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.

 

45.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 and special tools. Install the seal with its grooved side facing the tool.

 

46.Press the roller bearing (C) into the valve housing with a hydraulic press and special tool.

47.Apply vinyl tape (A) to the pinion shaft, then coat the vinyl tape with power steering fluid.

 

48.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).

49.Remove the vinyl tape from the pinion shaft, then remove any residue from the tape adhesive.

50.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.

 

51.Coat the special tool with power steering fluid, then slide it onto the rack, big end first.

52.Position the new O-ring (A) and new piston seal ring (B) on the special tool, 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, be sure to contract the seal ring using the special tool (sizing tool).
  • Replace piston's O-ring and seal ring as a set.

 

53.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.

54.Coat the piston seal ring (A) and the inside of the special tool with power steering fluid, then carefully slide the tool onto the rack and over the piston seal ring.

55.Move the special tool back and forth several times to make the piston seal ring fit snugly in the piston.

 

56.Set the new bushing (A) on the special tool, and insert the special tools into the cylinder housing (B).

 

57.Set the cylinder in a press, and install the bushing (A) into the bottom of the cylinder by pressing on the tool with press. Do not push on the tool with excessive force as it may damage the new bushing.

58.Coat the sliding surface of the special tool (A) and new cylinder end seal (B) with power steering fluid. Place the seal on the special tool with its grooved side (C) facing opposite the special tool.

 

59.Apply a thin coat of grease to the inside of the special tool.

60.Install the cylinder end seal (A) onto the steering rack (B) with its grooved side (C) toward the piston (D). Make sure the gap is special tool is opposite of rack teeth.

 

61.Separate the cylinder end seal from the special tool, then remove the special tool.

 

62.Install the new backup ring (A) on the steering rack, then place the backup ring and cylinder end seal (B) against the piston (C).

 

63.Mark (A) a position on the steering rack surface with a felt-tip marker, 7.7 mm (0.3 in.) from the rack end edges.

 

64.Grease the steering rack teeth, then insert the steering rack (A) into the cylinder (B). Be careful not to damage to inner surface of the cylinder wall and bushing with the rack edges.

 

65.Set the cylinder (A) in a press, then press the cylinder end seal (B) into the bottom of the cylinder until the mark (C) on the rack meets the edges (D) of the cylinder.

 

66.Coat the inside and outside surfaces of the new cylinder end seal (A) with power steering fluid.

 

67.Install the cylinder end seal onto the steering rack (B) with its grooved side (C) toward the piston. Push in the cylinder end seal with your finger.

68.Place the backup ring (D) on the cylinder end seal with its flat side facing upward. Then drive the backup ring in with the appropriate size socket wrench until the its surface is below the snap ring groove (E). Install the snap ring (F) in the groove.

69.Install the new lock screw (A) on the cylinder.

 

70.Install the new stop ring (B) in the groove (C) on the cylinder by expanding it with snap ring pliers. Be careful not to scratch or damage on the cylinder surface with the stop ring edges.

71.Coat the housing surface with multipurpose grease as shown.

 

72.Set the new boot bands (B) on the band installation grooves of boot A by aligning the tabs (C) with the holes (D) of the band. Do not close the ear portion of the boot band yet.

 

73.Compress boot A by hand, and apply vinyl tape (E) to the bellows so the boots stay collapsed and pulled back. Pass boot A over the cylinder so the smaller diameter end of the boot faces the gearbox housing.

74.Apply multipurpose grease to the sliding surface of the slider guide (A). Keep grease off of the rack-to-slider guide matching surfaces and the boot-to-slider guide matching surfaces.
Slide the steering rack all the way to left, and place the slider guide on the steering rack by aligning the bolt holes (B).

 

75.Hold the gearbox housing using a C-clamp (A) and the wooden block (B) as shown.

 

76.Push the cylinder (A) into the gearbox housing (B) so the notch (C) is aligned with the pin (D) inside of the gearbox housing.

 

77.Tighten the lock screw (A) by hand first, then install the special tool (B) on the lock screw. Lightly tighten the lock screw. Do not tighten the lock screw to specified torque yet.

 

78.Remove the special tool.

79.Coat the new O-ring (A) with grease, and carefully fit it on the valve housing.

 

80.Apply grease to the needle bearing (B) in the gearbox housing, then install the valve body unit (C) by engaging the gears. Note the valve body unit installation position (direction of the line connections). Tighten the flange bolts (D) to the specified torque.

81.Grease the sliding surface and circumference of the rack guide (A), and install it onto the gearbox housing. Wipe the grease off the threaded section of the housing.

 

82.Install the spring (B). Apply sealant to the middle of the threads on the rack guide screw (C), then install and tighten it to 25 N·m (2.5 kgf·m, 18 lbf·ft). Loosely install the locknut (D).

83.Center the steering rack within its stroke, and align the slider guide (B) with the holes (C) in boot A. Fit the slider guide to boot A by pressing around the edges of the holes securely.

 

84.Before installing the bracket (D), clean the mating surface of the 12 mm flange bolts (E) and bracket. Coat the new O-rings (F) with grease, and install them on the 12 mm flange bolts.

85.Loosely install the bracket on the steering rack by tightening the 12 mm flange bolts to 25 N·m (2.5 kgf·m, 18 lbf·ft).

86.Hold the gearbox housing using a C-clamp, then install the special tool on the lock screw (A). Retighten the lock screw to specified torque values.
Remove the special tool.

 

87.Retighten the 12 mm flange bolts (A) to specified torque values.

 

88.After tightening the 12 mm flange bolts, install a new stop washer (B) over one of bolt the heads (C). Be sure the tabs (D) of the stop washer are aligned with the flat surfaces (E) of the bolt head.

89.Clean off any grease or contamination from the boot installation grooves around on the housing.

90.Expand boot (A) by removing the vinyl tape, and fit the boot ends (B) in the installation grooves on the cylinder housing.

 

91.Close the ear portion (A) of the bands (B) with a commercially available pincers, Oetiker 1098 or equivalent (C).

 

92.Install the rack end plug (A).

 

93.Clean off any grease or contamination from the boot installation grooves (C) around on the housing.

94.Slide the steering rack, and adjust the distance between the cylinder housing end and the rack end plug end in the dimension to 70.5 mm (2.8 in.).
Install boot B, and set the boot end in the installation grooves in the cylinder housing and rack end plug properly. Install the clip (D) and boot guard (E). Install the new boot band (F) in the band grooves of boot B by aligning the tabs (G) with the holes (H) in the band.

95.Close the ear poriton (A) of the band (B) with a commercially available pincers, Oetiker 1098 or equivalent (C). Slide the rack right and left to be certain that the boots are not deformed or twisted.

 

96.Install a new lock washer (A) on the tie-rod (B) with the radiused side of the washer toward the tie-rod, and screw the tie-rod on the bracket (C). Repeat this step for the other tie-rod. Hold the bracket with one wrench, and tighten both tie-rods to the specified torque with another wrench.

 

97.Bend the lock washer against the flat spots on the bracket with a large pair of pliers.

 

98.Install the cylinder lines (A) and return line joint (B).

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.

 

99.Adjust the rack guide screw. After adjusting, check that the rack moves smoothly by sliding it right and left.