Chevrolet Full-size Cars 1968-1978 Repair Guide

Rear Main Oil Seal

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REMOVAL & INSTALLATION





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Fig. Fig. 1 Removing the lower half of the rear main seal



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Fig. Fig. 2 Removing the upper half of the rear main seal-crankshaft installed



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Fig. Fig. 3 Dimensions for making an oil seal installation tool



V8 Engines
 

  1. Refer to the Oil Pan Removal and Installation procedures in this information and remove the oil pan.
  2.  
  3. Remove the oil pump and the rear main bearing cap.
  4.  
  5. Using a small prybar, pry the oil seal from the rear main bearing cap.
  6.  
  7. Using a small hammer and a brass pin punch, drive the top half of the oil seal from the rear main bearing. Drive it out far enough, so it may be removed with a pair of pliers.
  8.  
  9. Using a non-abrasive cleaner, clean the rear main bearing cap and the crankshaft.
  10.  
  11. Fabricate an oil seal installation tool from 0.004 in. shim stock, shape the end to 1 / 2 in. long by 11 / 64 in. wide.
  12.  
  13. Coat the new oil seal with engine oil; DO NOT coat the ends of the seal.
  14.  
  15. Position the fabricated tool between the crankshaft and the seal seat in the cylinder case.
  16.  
  17. Position the new half seal between the crankshaft and the top of the tool, so that the seal bead contacts the tip of the tool.
  18.  

Make sure that the seal lip is positioned toward the front of the engine.

  1. Using the fabricated tool as a shoe horn, to protect the seal's bead from the sharp edge of the seal seat surface in the cylinder case, roll the seal around the crankshaft, when the seal's ends are flush with the engine block, remove the installation.
  2.  
  3. Using the same manner of installation, install the lower half onto the lower half of the rear main bearing cap.
  4.  
  5. Apply sealant to the cap-to-case mating surfaces and install the lower rear main bearing half to the engine; keep the sealant off of the seal's mating line.
  6.  
  7. Install the rear main bearing cap bolts and torque to 10-12 ft. lbs. Using a lead hammer, tap the crankshaft forward and rearward, to line up the thrust surfaces. Torque the main bearing bolts to specification.
  8.  
  9. Install the oil pan. Fill the engine with oil. Start the engine and check for leaks.
  10.  

 
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