GM Service Manual Online
For 1990-2009 cars only

Special Tools

J 34993 Cylinder Alignment Rods

Removal Procedure


    Object Number: 1252013  Size: SH
  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging.
  2. Discharge the A/C system. Refer to Refrigerant Recovery and Recharging.
  3. Remove the compressor. Refer to Air Conditioning Compressor Replacement.
  4. Drain the oil from compressor into a suitable container. Measure and record the amount of oil drained from the compressor. Discard the used oil.
  5. Remove the clutch plate and hub assembly. Refer to Compressor Clutch Plate/Hub Assembly Replacement.
  6. Remove the clutch rotor and bearing. Refer to Clutch Rotor and/or Bearing Replacement.
  7. Remove the clutch coil. Refer to Air Conditioning Clutch Coil Replacement.
  8. Remove the compressor through-bolts. Remove and discard the gaskets.
  9. Using a wooden block and a plastic-headed hammer, tap around the edge of the rear head to disengage the head from the compressor cylinder. Separate the rear head, the head gasket, the rear valve plate, the suction reed plate, and the cylinder-to-rear head O-ring. Discard the head gasket and the O-ring.

Installation Procedure


    Object Number: 1256093  Size: SH
  1. Place the rear head on a clean, flat surface. Position the head with the control valve at the 6 o'clock position.
  2. Install the J 34993  (1) in the mounting holes at the 11 o'clock and the 5 o'clock positions.
  3. Install the head gasket over the J 34993 with the elongated hole at the upper left pin, the 11 o'clock position.
  4. Install the rear head valve plate over the guide pins with the elongated hole at the upper left pin. Lower the rear head valve plate into place.
  5. Install the suction reed plate over the J 34993 . Remove the alignment rod at the 5 o'clock position.
  6. Lubricate the cylinder to the new rear head O-ring with clean polyalkaline glycol (PAG) refrigerant oil.
  7. Install the O-ring in the cylinder O-ring groove. The O-ring seal surface of the head may be lubricated to ease assembly.
  8. With the O-ring in place on the rear of the cylinder assembly, locate the relief boss for the compressor guide pin at the 6 o'clock position, directly above the hole in the side of the rear head. Carefully lower the cylinder and the front head assembly over the guide pin to the rear head.
  9. Press the cylinder and the compressor housing assembly down onto the rear head using both hands.
  10. Caution: Refer to Fastener Caution in the Preface section.

  11. Add the new through-bolt gasket to the through-bolts and install it into the compressor assembly. Four of the through-bolts must thread into the rear head before removing the alignment rod. Alternately tighten the through-bolts in progressive torque sequence to 10 N·m (89 lb in).
  12. Add new PAG refrigerant oil as determined in step 1 of the removal procedure.
  13. Place the shaft nut on the shaft and rotate the compressor shaft several times.
  14. Perform a leak test on the compressor. Refer to Leak Testing.
  15. Install the clutch coil. Refer to Air Conditioning Clutch Coil Replacement.
  16. Install the clutch rotor and bearing. Refer to Clutch Rotor and/or Bearing Replacement.
  17. Install the clutch plate and hub assembly. Refer to Compressor Clutch Plate/Hub Assembly Replacement.
  18. Install the compressor. Refer to Air Conditioning Compressor Replacement.
  19. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging.