GM Storm/Spectrum 1985-1993 Repair Guide

Power Rack and Pinion

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DISASSEMBLY



Spectrum
  1. Insert the steering unit into a vise, placing a piece of wood or soft metal between the unit and the jaws of the vise.
  2.  
  3. Remove the tie-rod end and the boot.
  4.  
  5. Straighten the bent part of the locking washer between the inner tie-rod and the rack. A new washer should be used when reassembled.
  6.  
  7. Remove the tie-rod from the rack.
  8.  
  9. Disconnect the right and left pipe assemblies between the valve housing and the cylinder.
  10.  
  11. Loosen the adjusting plug nut, remove the spring and rack bearing.
  12.  
  13. Rotate the pinion gear shaft until the pinion flat is parallel or aligned with the rack. Then measure the length of the rack exposed from the assembly. This measurement will be used to reassemble the unit.
  14.  
  15. Remove the valve/pinion housing assembly.
  16.  
  17. Remove the adjusting shims.
  18.  
  19. Remove retaining ring from the right side.
  20.  
  21. Withdraw the rack assembly, on the right side, and the seal holder together. Carefully remove the rack from the housing to avoid damaging the inner housing face.
  22.  
  23. Remove the inner rack seal and the shock dampener.
  24.  
  25. Remove the piston and the O-ring seals from the rack.
  26.  
  27. With a soft head hammer, drive the valve assembly from the housing.
  28.  
  29. Drive the bearing and seal from the valve housing with tool J 33997, or the equivalent.
  30.  
  31. Remove the snapring from the spool end of the valve assembly, then slide the spool, seals and spacer. Do not remove the teflon seals. The valve is serviced as an assembly.
  32.  

Storm
  1. Insert the steering unit into a vise, placing a piece of wood or soft metal between the unit and the jaws of the vise.
  2.  
  3. Retaining ring and dust boot from the rack.
  4.  
  5. Remove the clamps from the tie rod boots. Separate the boots from the rack and slide them down the tie rods. Unstake the locking washers between inner tie rods and the rack.
  6.  
  7. Remove the right tie rod assembly from the rack.
  8.  
  9. Remove the left tie rod assembly from the rack.
  10.  
  11. Loosen the adjusting plug nut, remove the spring and rack plunger.
  12.  
  13. Rotate the pinion gear shaft until the pinion flat is parallel or aligned with the rack. Then measure the length of the rack exposed from the assembly. This measurement will be used to reassemble the unit.
  14.  
  15. Remove the valve plug.
  16.  
  17. Remove the pinion fixing nut.
  18.  
  19. Remove pinion retaining snapring.
  20.  
  21. Remove the pinion valve assembly from the rack.
  22.  
  23. Remove the retaining ring from the right side of the rack housing.
  24.  
  25. Withdraw the rack from the housing.
  26.  
  27. Using the inner rack seal remover J 38304-5 or the equivalent, remove the inner rack seal and the shock dampener.
  28.  
  29. Remove the lower pinion bearing from the rack housing.
  30.  
  31. Using the J38304-1 lower pinion valve housing seal and bearing remover or the equivalent, remove the bearing and seal from the valve housing.
  32.  

ASSEMBLY



Storm
  1. Install the inner rack seal onto J 33997-3 rack seal ring installer, using a J 33997-2 rack seal ring expander. Install inner rack seal into the rack, using a J 33997-3 rack seal ring installer.
  2.  
  3. Install the upper bearing and seal into the pinion valve housing, using a J 38304-4 lower pinion valve housing seal and bearing installer.
  4.  
  5. Install the rack into the housing and seat the inner rack seal, using the rack piston ring installer J 38304-7 and the inner rack seal installer J 38304-6, or equivalents.
  6.  
  7. Insert the seal holder into the housing.
  8.  
  9. Install the retaining ring on the seal holder.
  10.  
  11. Install the pinion valve assembly into the housing using J 38304-8 pinion ring compressor.
  12.  
  13. Install the lower bearing on the pinion valve.
  14.  
  15. Install the pinion fixed nut and tighten it to 29 ft. lbs. (39 Nm).
  16.  
  17. Install the cap on the bottom of the pinion valve housing.
  18.  
  19. Install the rack plunger and the plunger plug. Tighten the rack plunger adjusting plug to 44 in. lbs. (5 Nm). Loosen the plug and tighten again to 44 in. lbs. (5 Nm), then back the nut off 26 degrees and tighten the locking nut.
  20.  
  21. Install the upper pinion valve seal.
  22.  
  23. Install the retaining ring on the upper pinion valve seal.
  24.  
  25. Install the left tie rod assembly. Tighten the inner tie rod to 65 ft. lbs. (88 Nm). Peen the stake washer.
  26.  
  27. Install the left tie rod boot.
  28.  
  29. Install the right tie rod assembly. Tighten the inner tie rod to 65 ft. lbs. (88 Nm). Peen the stake washer.
  30.  
  31. Install the right tie rod boot.
  32.  

Valve/Pinion Assembly
SPECTRUM
  1. Install the spacer. With tool J33997-7 or equivalent, slide the oil seal onto the shaft, with the flat side of the seal toward the spacer.
  2.  
  3. Install the valve spool. Do not force the spool onto the pinion shaft. If it does not slide onto the pinion shaft, use tool J 33997-4 or equivalent to compress the seal ring, then install the spool.
  4.  
  5. Install the snapring on the shaft at the spool.
  6.  
  7. Use a press to install the upper bearing and, using tool J33997-4 or equivalent, install the seal into the valve housing with the flat side toward the bearing.
  8.  
  9. Use tool J33997-8 or equivalent to compress the seal rings onto the spool housing and install pinion/valve assembly into the valve housing.
  10.  
  11. Place tool J 33997-9 on the upper pinion shaft. Install the pinion/valve assembly into the valve housing.
  12.  

Rack Piston
SPECTRUM
  1. Use tool J 33997-6 or equivalent to compress the seal ring. Install the seal onto the rack piston.
  2.  
  3. Apply grease to the rack gear surfaces. Install the seal into the seal holder with the flat end of the seal first. Install the seal holder assembly using the seal protector tool J 33997-9 or equivalent.
  4.  
  5. Install the shock damper ring using tools J 35527 and J 7079-2 or equivalents.
  6.  
  7. Install inner rack seal on the gear side of the rack. The shim stock should be used to protect the seal from the rack gear surface. The flat end of the seal should be away from the rack piston.
  8.  
  9. Install the rack assembly and push the seal holder into the housing. Install the retaining ring.
  10.  
  11. Move the rack assembly into the housing as far as possible and measure the distance between the end of the holder and the tip of the rack shaft. The seals are positioned correctly when the distance is 10mm or more.
  12.  

Valve/Housing Adjustment
SPECTRUM
  1. Center the rack. Measure the distance between the end of the seal holder and the end of the rack. It should be adjusted to 2.5 in. (63.5 mm).
  2.  
  3. Apply grease to the pinion gear teeth and the pinion ball bearings.
  4.  
  5. Using the valve assembly repair kit, install all seven adjusting shims.
  6.  
  7. Install the pinion/valve assembly to the housing and carefully snug the two bolts, 1/4 turn each until snug.
  8.  
  9. Using a feeler gauge, measure the clearance between the valve and gear housings. Remove one shim for each 0.002 in. (0.05 mm) of clearance. The final clearance should be less than 0.002 in. (0.05 mm).
  10.  
  11. Set the rack to the dimension recorded during removal. Install the pinion with the flat side parallel to the rack.
  12.  
  13. Use RTV No. 1052366 or equivalent to seal the mating surfaces of the valve and the steering housing, and tighten to 18 ft. lbs. (25 Nm).
  14.  
  15. Lubricate the rack plunger well and install. Install the spring, adjusting plug and the locknut.
  16.  
  17. Tighten the adjusting plug to 3.6 ft. lbs. (5.0 Nm).
  18.  
  19. Loosen the plug and repeat Step 9.
  20.  
  21. Back off the adjusting plug 30-35 degrees. Tighten the locknut.
  22.  
  23. Measure the pinion shaft preload. If the preload is not between 0.4-1.2 ft. lbs. (0.6-1.6 Nm), loosen the locknut and readjust the plug torque. When the acceptable preload is achieved, apply liquid thread lock to the locknut and tighten the locknut to 49 ft. lbs. (66 Nm).
  24.  

Rack Unit Assembly
SPECTRUM
  1. Install the right and left cylinder pipes. Tighten the fittings to 14 ft. lbs. (20 Nm).
  2.  
  3. Install the inner tie-rod and a new locking washer to the rack end. Tighten to 65 ft. lbs. (88 Nm). Protect the rack from the vise. Stake the locking washer to the flat of the inner tie-rod. Apply grease to the inner surface of the small opening in the boot.
  4.  
  5. Install a new boot over the inner tie-rod. Install a new boot clamp and wire.
  6.  
  7. Install the tie-rod nut and attach the tie-rod end.
  8.  
  9. Adjust the tie-rod so the length from the outer side of the boot clamp to the outer side of the locknut is 7.5 in. (190.4 mm).
  10.  
  11. Tighten the tie-rod locking nut to 40 ft. lbs. (54 Nm).
  12.  

 
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