GM Corvette 1984-1996 Repair Guide

Rear Main Seal

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REMOVAL & INSTALLATION



5.7L (VIN 8, P and 5) Engine

The rear main seal on 1984-85 vehicles is a 2-piece seal. On 1986-91 vehicles, the rear main seal is a 1-piece seal.

1984-85 vehicles

See Figures 1, 2, 3 and 4

Always replace the upper and lower seal as a unit. On these vehicles, both halves of the seal can be replaced without removing the crankshaft. Be very careful when installing the seal to protect the sealing bead located in the channel on the outer diameter of the seal. There is an installation tool which can be used to protect the seal during positioning.

  1. Remove the oil pan and oil pump.
  2.  
  3. Remove the oil seal from the bearing cap by carefully prying it from the bottom with a small prytool.
  4.  



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Fig. Fig. 1: Carefully pry the lower half of the seal out of the bearing cap

  1. To remove the upper half of the seal, use a small hammer to tap a brass punch on one end of the seal until it protrudes far enough to be removed with pliers.
  2.  



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Fig. Fig. 2: Tap the upper half of the seal with a hammer and drift, then remove the seal with pliers

  1. Use a non abrasive cleaner to removal all of the sealant and foreign material from the cylinder case bearing cap and crankshaft.
  2.  
  3. Inspect the components for nicks, scratches, burrs and/or machining defects at all sealing surfaces, case assembly and crankshaft.
  4.  
  5. Coat the seal lips and seal bead with light engine oil, but keep the oil off the seal mating ends.
  6.  
  7. Position the tip of the installation tool between the crankshaft and seal seat in the cylinder case.
  8.  



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Fig. Fig. 3: Oil seal installation tool

  1. Place the seal between the crankshaft and tip of the tool so the seal bead contacts the tip of the tool. Make sure the oil seal lip is positioned toward the front of the engine.
  2.  



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Fig. Fig. 4: During installation, make sure the oil seal lip is toward the front of the engine

  1. Roll the seal around the crankshaft, using the tool as a "shoe horn" to protect the seal bead from the sharp corner of the seal seat surface in the cylinder case. The tool must remain in position until the seal is properly positioned with both ends flush with the block.
  2.  
  3. Remove the tool, being careful not to withdraw the seal.
  4.  
  5. Instlal the seal half in the bearing cap, again using the tool as a "shoe horn", feeding the seal into the cap using light pressure with your thumb and finger.
  6.  
  7. Instlal the bearing cap to the case with sealant applied to the cap-to-case interface, being careful to keep the sealant off the seal split line.
  8.  
  9. Install the rear main bearing cap (with new seal) and tighten to 10-12 ft. lbs. (14-16 Nm). Tap the end of the crankshaft rearward then forward with a lead hammer. This will line up the thrust surfaces.
  10.  

1986-96 vehicles

See Figures 5, 6 and 7

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the transmission assembly.
  4.  
  5. For manual transmission vehicles, remove the clutch cover and disc assembly.
  6.  
  7. Remove the flywheel bolts and remove the flywheel from the vehicle.
  8.  
  9. Using the notches provided in the seal retainer and a small suitable tool, pry the old seal from the engine. Be careful not to nick the crankshaft sealing surface when removing the seal.
  10.  



Click image to see an enlarged view

Fig. Fig. 5: Rear main seal removal-1986-91 vehicles, except 5.7L (VIN J) engine

To install:


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Fig. Fig. 6: Exploded view of the rear main seal and related components

  1. Lubricate the inside and outside of a new seal with clean engine oil.
  2.  
  3. Install the seal on tool J-35621 or equivalent rear main seal installer.
  4.  



Click image to see an enlarged view

Fig. Fig. 7: Use the proper tool to install the rear main seal

  1. Thread the screws of the tool into the rear of the crankshaft and tighten the screws snugly to assure proper seal alignment and installation.
  2.  
  3. Tighten the tool wingnut until it bottoms and then remove the tool.
  4.  
  5. Install the flywheel and tighten the bolts to 74 ft. lbs. (100 Nm).
  6.  
  7. If equipped, install the clutch cover and disc assembly.
  8.  
  9. Install the transmission assembly.
  10.  
  11. Lower the vehicle and connect the negative battery cable.
  12.  

5.7L (VIN J) Engine

See Figure 8

  1. Disconnect the negative battery cable.
  2.  
  3. Remove transmission assembly.
  4.  
  5. Remove the clutch cover and disc assembly.
  6.  
  7. Remove the flywheel bolts and flywheel.
  8.  
  9. Remove the screws attaching the crankshaft rear main oil seal/housing assembly to the cylinder case.
  10.  
  11. Remove the retaining screws, then remove the seal/housing assembly from the engine.
  12.  
  13. Remove the seal from the housing.
  14.  



Click image to see an enlarged view

Fig. Fig. 8: Location of the crankshaft rear main seal-5.7L (VIN J) engine

To install:
  1. Lubricate the seal lip with engine oil.
  2.  
  3. Install seal into housing using crankshaft rear seal tool J-37312 or equivalent. Make sure the seal is installed 1.0-1.5mm below the housing surface.
  4.  
  5. Install the housing and tighten the bolts to 89 inch lbs. (10 Nm).
  6.  
  7. Apply Loctite® 242 or equivalent, to the bolts threads, then install the flywheel and tighten the bolts to 74 ft. lbs. (100 Nm).
  8.  
  9. Install the clutch cover and disc assembly.
  10.  
  11. Install the transmission assembly.
  12.  
  13. Connect the negative battery cable.
  14.  

 
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