GM Caprice 1990-1993 Repair Guide

Rear Main Oil Seal

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REMOVAL AND INSTALLATION



The Oldsmobile produced 5.0L (VIN Y) engine came equipped with either a 2-piece neoprene seal or a rope seal. All other Chevrolet produced engines come equipped with a new 1-piece neoprene seal.

1-Piece Neoprene Seal

See Figures 1 and 2



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Fig. Fig. 1: Rear main 1-piece oil seal removal



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Fig. Fig. 2: Rear main 1-piece oil seal tool and installation

The rear main seal is a one piece unit. It can be removed or installed without removing the oil pan or crankshaft.

  1. Jack up your vehicle and support it with jackstands.
  2.  
  3. Remove the transmission assembly.
  4.  
  5. Remove the flywheel and block plate assembly.
  6.  
  7. Using a suitable tool, pry the old seal out.
  8.  
  9. Inspect the crankshaft for nicks or burrs, correct as required.
  10.  
  11. To install, clean the area and coat the seal with engine oil. Install the seal onto tool J-34686 or equivalent. Install the seal into the engine.
  12.  
  13. Install the flywheel and block plate. Torque to specification.
  14.  
  15. Install the transmission.
  16.  
  17. Check the fluid levels, start the engine and check for leaks.
  18.  

2-piece Neoprene Seal

See Figures 3, 4, 5 and 6



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Fig. Fig. 3: Rear main 2-piece oil seal lower half removal



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Fig. Fig. 4: Rear main 2-piece oil seal upper half removal



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Fig. Fig. 5: Applying sealer to main bearing cap



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Fig. Fig. 6: Fabricated oil seal installation tool

Both halves of the rear main oil seal can be replaced without removing the crankshaft. Always replace the upper and lower seal together. The lip should face the front of the engine. Be very careful that you do not break the sealing bead in the channel on the outside portion of the seal while installing it. An installation tool can be fabricated to protect the seal bead.

  1. Remove the oil pan, oil pump and rear main bearing cap.
  2.  
  3. Remove the oil seal from the bearing cap by prying it out.
  4.  
  5. Remove the upper half of the seal with a small punch. Drive it around far enough to be gripped with pliers.
  6.  
  7. Clean the crankshaft and bearing cap.
  8.  
  9. Coat the lips and bead of the seal with light engine oil, keeping oil from the ends of the seal.
  10.  
  11. Position the fabricated tool between the crankshaft and seal seat.
  12.  
  13. Position the seal between the crankshaft and tip of the tool so that the seal bead contacts the tip of the tool. The oil seal lip should face THE front of the engine.
  14.  
  15. Roll the seal around the crankshaft using the tool to protect the seal bead from the sharp corners of the crankcase.
  16.  
  17. The installation tool should be left installed until the seal is properly positioned with both ends flush with the block.
  18.  
  19. Remove the tool.
  20.  
  21. Install the other half of the seal in the bearing cap using the tool in the same manner as before. Light thumb pressure should install the seal.
  22.  
  23. Install the bearing cap with sealant applied to the mating areas of the cap and block. Keep sealant from the ends of the seal.
  24.  
  25. Torque the rear main bearing cap to specifications.
  26.  
  27. Install the oil pump and oil pan.
  28.  
  29. Fill the engine with engine oil, start the engine and check for leaks.
  30.  

Rope Seal

See Figures 5, 7, 8 and 9



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Fig. Fig. 7: Using the rope seal packing tool



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Fig. Fig. 8: Using the rope seal guide tool



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Fig. Fig. 9: Install the rope seal in the cap using tool J-29590 and cut the seal ends flush with the main cap

The following procedure is only to be used as an oil seal repair while the engine is in the vehicle. Whenever possible the crankshaft should be removed and a new complete rope seal installed.

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the engine oil and remove the oil pan.
  4.  
  5. Remove the rear main bearing cap.
  6.  
  7. Insert packing tool J-29114-2 or equivalent, against 1 end of the seal in the cylinder block. Drive the old seal gently into the groove until it is packed tight. This will vary from 1 / 4 inch to 3 / 4 inch depending on the amount of pack required.
  8.  
  9. Repeat the procedure on the other end of the seal.
  10.  
  11. Measure the amount the seal was driven up on one side and add 1 / 16 inch. Using a suitable cutting tool, cut that length from the old seal removed from the rear main bearing cap. Repeat the procedure for the other side. Use the rear main bearing cap as a holding fixture when cutting the seal.
  12.  
  13. Install guide tool J-29114-1 or equivalent, onto the cylinder block.
  14.  
  15. Using the packing tool, work the short pieces cut in Step 6 into the guide tool and then pack into the cylinder block. The guide tool and packing tool are machined to provide a built in stop. Use this procedure for both sides. It may help to use oil on the short pieces of the rope seal when packing them into the cylinder block.
  16.  
  17. Remove the guide tool.
  18.  
  19. Apply Loctite 414 or equivalent, to the seal groove in the rear main bearing cap. Within 1 minute, insert a new seal into the groove and push into place with tool J-29590 until the seal is flush with the block. Cut the excess seal material with a sharp cutting tool at the bearing cap parting line.
  20.  
  21. Apply a thin film of chassis grease to the rope seal. Apply a thin film of RTV sealant on the bearing cap mating surface around the seal groove. Use the sealer sparingly.
  22.  
  23. Plastigage the rear main bearing cap as outlined in MEASURING REAR MAIN CLEARANCE in this Section and check with specification. If out of specification, check for fraying of the rope seal which may be causing the cap to not seat properly.
  24.  
  25. Install all remaining components and inspect for leaks.
  26.  

 
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