Overhaul

Steering Gear

WARNING: Wear safety glasses while removing and reinstalling circlips and retaining ring.

NOTE: Absolute cleanliness is essential when overhauling the power steering gear.

NOTE: This procedure is for the Adwest steering gear only.



Disassembly

1. Remove steering gear from vehicle. Mark drop arm and steering gear for realignment on assembly. Remove drop arm using extractor tool No. LRT-57-012. Loosen drop arm securing nut, but do not remove before using extractor. Remove dirt excluder from output shaft.






2. Drain oil, remove blanking plugs and bleed screw. Hold steering gear over drain tin, turn input shaft from lock to lock, until oil is drained. Refit bleed screw.
3. Rotate retainer ring until one end is 12 mm from extractor hole. Using a drift through hole in cylinder, lift retaining ring from groove in cylinder bore.
4. Remove retainer ring, using a screwdriver.
5. Turn input shaft left to lock on LH drive, right to lock on RH drive, until piston pushes out cover. Turn input shaft fully in opposite direction, applying pressure to piston.






6. Remove set screw retaining rack pad adjuster.
7. Remove rack adjuster and pad.
8. Remove sector shaft adjuster locknut.
9. Remove four bolts from sector shaft cover.
10. Screw in sector shaft adjuster until cover is removed.
11. Slide out sector shaft.






12. Remove piston, a bolt screwed into piston will assist removal.
13. Remove input shaft dirt excluder.
14. Remove worm adjuster locknut using "C" wrench tool No. LRT-57-007.
15. Remove worm adjuster using wrench tool No. LRT-57-006.






16. Tap splined end of shaft to free bearing.
17. Remove bearing cup and caged ball bearing assembly.
18. Remove valve and worm assembly.

NOTE: If difficulty is experienced, warm the casing and bearing assembly. Cool bearing cap using a mandrel and tap steering gear on a bench.

19. Remove inner bearing cage, cup and shim washers. Retain shims for reassembly.






CAUTION: Do not remove sector shaft bearings from casing. Replacement parts are not available. If sector shaft bearings are worn, install a new steering gear.

20. Remove circlip and seal from sector shaft housing bore.

CAUTION: The use of a seal puller is recommended to prevent damage to casing, and possible oil leaks.

21. Remove dirt excluder, circlip and seal from input shaft housing bore.






22. Discard all rubber seals and provide replacements.

Rubber Seals:

NOTE: A rubber seal is installed behind plastic ring on rack piston. Discard seal and plastic ring.

23. Examine piston bore for scoring and wear.
24. Examine feed tube.
25. Install a new feed tube if damaged. Tighten union to: 20 Nm (15 ft. lbs.).

Steering Gear Case:

26. Check there is no side play on roller.
27. If side play on roller exists install a new sector shaft.
28. Check condition of adjuster screw threads. Check adjuster end float. Install new adjuster if end float exceeds 0.15 mm, 0.006 inch.
29. Examine bearing areas on shaft for excessive wear.
30. Examine gear teeth for uneven or excessive wear.
31. Inspect cover and bearing. If worn or damaged, install a new steering gear.
32. The locknut is also a fluid seal. Install new nut at overhaul.







33. Examine bearing areas for wear. The areas must be smooth and not indented.
34. Examine worm track which must be smooth and not indented.

NOTE: Any sign of wear makes it essential to fit new valve and worm assembly.

35. Check for wear on torsion bar assembly pin. No free movement should exist between input shaft and torsion bar or between torsion bar and worm.






NOTE: Any sign of wear makes it essential to install new valve and worm assembly.

36. Examine valve rings for cuts, scratches and grooves. The valve rings should be free to rotate in grooves. Renew the valve and worm assembly if any faults are found.
37. Examine ball races and cups for wear and general condition.
38. If ball cage has worn against bearing cup, fit replacements.
39. Bearing balls must be retained by cage.
40. Bearing and cage repair is carried out by complete replacement of assembly.






41. Examine thrust pad for scores.
42. Examine adjuster for wear in pad seat.
43. Install new sealing ring to rack adjuster.






44. Examine for excessive wear on rack teeth.
45. Ensure thrust pad bearing surface is free from scores and wear.
46. Ensure piston outer diameters are free from burrs and damage.
47. Examine seal and ring groove for scores and damage.






Assembly

1. Install new ring to piston. Warm nylon seal and install to piston.
2. Slide piston assembly into cylinder with rack tube outwards.

NOTE: When installing replacement oil seals lubricate with recommended fluid and ensure absolute cleanliness.

3. Install oil seal, lip side first.
4. Install extrusion washer.
5. Install dust seal, lipped side last.
6. Install circlip.






7. Reinstall original shims and inner bearing cup. Use Petroleum Jelly to aid assembly.

NOTE: If original shims are not used, install shims of 0.76 mm, (0.030 inch) thickness.

8. Install inner cage and bearings assembly.
9. Install valve and worm assembly.
10. Install outer cage and bearings assembly.
11. Install outer bearing cup.





12. Install new worm adjuster sealing ring.
13. Loosely screw adjuster into casing.
14. Install locknut, do not tighten.
15. Turn in worm adjuster until end float is almost eliminated. Ensure bearing cages are seated correctly.
16. Measure maximum rolling torque of valve and worm assembly, using a torque wrench and spline socket tool No. LRT-57-025.






17. Turn in worm adjuster while rotating shaft to increase figure measured to 0.56 Nm (0.41 ft. lbs.).
18. Back off worm adjuster 1/4 turn. Turn in worm adjuster to increase reading found in step 14 by 0.21-0.34 Nm (0.15-0.25 ft. lbs.) with locknut tight, 100 Nm (74 ft. lbs.) Use worm adjusting wrench tool No. LRT-57-006 and locknut wrench tool No. LRT-57-028.
19. Screw slave bolt into piston to aid assembly.
20. Install piston and rack so piston is 70 mm (2.75 inch) from outer end of bore.
21. Install sector shaft using seal saver tool No. LRT-57-021. Align roller with cut out in casing. Push in sector shaft while rotating input shaft to allow sector roller to engage worm.






22. Install rack adjuster and thrust pad to engage rack. Back off half turn on adjuster.
23. Loosely install new nylon pad and adjuster set screw assembly.






24. Install new sealing ring to cover.
25. Align cover with casing.
26. Screw cover assembly fully on to sector shaft adjuster screw.
27. If necessary back off sector shaft adjuster screw. Tap cover in place to allow cover to joint fully with casing.

NOTE: Before tightening fixings, rotate input shaft to ensure sector shaft roller is free to move in valve worm. If initial resistance is left, turn adjuster screw approximately two turns in a clockwise direction.

28. Install cover bolts. Tighten to 75 Nm (55 ft. lbs.).






29. Install new square section seal to cover.
30. Remove slave bolt from piston. Press cover into cylinder just to clear retainer ring groove.
31. Install retaining ring to groove with one end of ring positioned 12 mm (0.472 inch) from extractor hole.






NOTE: Reinstall drop arm and tighten nut sufficiently to ensure that no backlash exists between drop arm and sector shaft.

32. To set worm on center, rotate input shaft to full inner-lock full right lock for a left hand drive vehicle, full left lock for a right hand drive vehicle. Rotate input shaft back towards center two full turns.
33. The box is now on center and can be adjusted.
34. Hold input shaft and rock pitman arm to establish backlash is present.
- Continue rocking and slowly turn sector shaft adjusting screw clockwise. Continue rotating adjuster screw until backlash has almost been eliminated.
35. Reinstall locknut and tighten.

NOTE: It is important steering gear is centralized before any adjustments are made.

36. Check maximum rolling torque one and a quarter turns either side of center position, using a torque wrench and spline socket tool No. LRT-57-025. Rotate adjuster screw to obtain across center, torque of 0.34 Nm, (0.25 ft. lbs.) plus torque figure measured at one and a quarter turns. Tighten adjuster locknut to 60 Nm, (44 ft. lbs.).
36. Turn in rack adjuster to increase figure measured in previous instruction by: 0.23-0.34 Nm (0.17-0.25 ft. lbs.). The final figure may be less, but must not exceed 1.35 Nm (1.0 ft. lbs.).
37. Lock rack adjuster in position with grub screw. Tighten to: 5 Nm, (4 ft. lbs.).
^ With input shaft rotated from lock to lock, rolling torque figures should be greatest across center position and equally disposed about center position.
^ The condition depends on value of shimming installed between valve and worm assembly inner bearing cup and casing.
^ The original shim washer value will give correct torque peak position unless major components have been replaced.






38. With input coupling shaft toward the operator, turn shaft fully counter-clockwise.
39. Check torque figures obtained from lock to lock using torque wrench and spline socket.






40. Check also for equal engagement either side of center.
41. Note where greatest figures are recorded relative to steering position. If greatest figures are not recorded across center of travel (steering straight-ahead), adjust as follows:
^ If torque peak occurs before center position, add to shim washer value.
^ If torque peak occurs after center position, subtract from shim washer value, refer to installing valve and worm assembly.
^ Shim washers are available as follows: 0.03mm, (0.001 inch), 0.07mm, (0.003inch), 0.12mm, (0.004 inch) and 0.24mm, (0.008inch).

NOTE: Adjustment of 0.07mm, 0.003 inch to shim value will move torque peak area by 1/4 turn on the shaft.

CAUTION: When reshimming valve and worm, extreme caution must be exercised to prevent seal damage during reassembly.


42. Install seal, lip side first, into housing.
- Use seal saver tool No. LRT-57-016 and seal installer tool No. LRT-57-026. Note that seal is installed to a depth of 4.75-5.00 mm, (0.19-0.20 inch) from face of box.
43. Secure seal with circlip.
44. Smear inner lip of dirt excluder with grease. Install dirt excluder (94) using installer tool No. LRT-57-027. When installed correctly outer shoulder of excluder is 4.00-4.50 mm, (0.16-0.18 inch) from face of box, dimension -X-.





45. Remove drop arm. Smear inner lip of dirt excluder with PTFE, or equivalent, grease and reinstall, ensuring outer lip is flush with casing.
46. With input shaft on center, align assembly marks on pitman arm and steering gear.
^ Install pitman arm to steering gear using a new tab washer.
^ Tighten nut to: (175 Nm, 130 ft. lbs.) bend over tab.
46. Install steering gear.