Roadmaster 1992

Rear Main Seal

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Removal & Installation



1-Piece Neoprene Seal

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

  1. Before servicing the vehicle, refer to the Precautions Section.
    NOTE
    Disconnecting the negative battery cable on some vehicles may interfere with the functions of the on-board computer systems and may require the computer to undergo a relearning process, once the negative battery cable is reconnected.


    NOTE
    If working near and/or around the SRS system and components, be sure to properly disable the SRS system. See disarming/arming the SRS system.

  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Raise and safely support the vehicle.
  6.  
  7. Remove the transmission.
  8.  
  9. Remove the flexplate.
  10.  
  11. Using a suitable tool, pry the old seal out.
  12.  
  13. Inspect the crankshaft for nicks or burrs, correct as required.

    Click image to see an enlarged view

    Fig. Rear main 1-piece oil seal removal-1991-1993



    Click image to see an enlarged view

    Fig. Rear main 1-piece oil seal tool and installation-1991-1993

  14.  

To install:


NOTE
Be sure to use new fasteners, as required.


NOTE
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread sealer are identified. Do not use paints, lubricants or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners.

  1. 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.
  2.  
  3. Install the flexplate. Torque bolts to specification.
  4.  
  5. Install the transmission.
  6.  
  7. Check the fluid levels, start the engine and check for leaks.
  8.  
  9. Using the GM diagnostic scan tool or aftermarket equivalent reprogram the necessary systems and components. Be sure to follow the scan tool manufacturer-s directions.
  10.  

2-Piece Neoprene Seal

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. Before servicing the vehicle, refer to the Precautions Section.
    NOTE
    Disconnecting the negative battery cable on some vehicles may interfere with the functions of the on-board computer systems and may require the computer to undergo a relearning process, once the negative battery cable is reconnected.

  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Raise and safely support the vehicle.
  6.  
  7. Drain the engine oil. Be sure to properly dispose of used oil.
  8.  
  9. Remove the oil pan, oil pump and rear main bearing cap.
  10.  
  11. Remove the oil seal from the bearing cap by prying it out.
  12.  
  13. Remove the upper half of the seal with a small punch. Drive it around far enough to be gripped with pliers.

    Click image to see an enlarged view

    Fig. Rear main 2-piece oil seal lower half removal-1991-1993



    Click image to see an enlarged view

    Fig. Rear main 2-piece oil seal upper half removal-1991-1993



    Click image to see an enlarged view

    Fig. Applying sealer to main bearing cap-1991-1993



    Click image to see an enlarged view

    Fig. Fabricated oil seal installation tool-1991-1993

  14.  

To install:


NOTE
Be sure to use new fasteners, as required.


NOTE
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread sealer are identified. Do not use paints, lubricants or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners.

  1. Clean the crankshaft and bearing cap.
  2.  
  3. Coat the lips and bead of the seal with light engine oil, keeping oil from the ends of the seal.
  4.  
  5. Position the fabricated tool between the crankshaft and seal seat.
  6.  
  7. 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.
  8.  
  9. Roll the seal around the crankshaft using the tool to protect the seal bead from the sharp corners of the crankcase.
  10.  
  11. The installation tool should be left installed until the seal is properly positioned with both ends flush with the block.
  12.  
  13. Remove the tool.
  14.  
  15. 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.
  16.  
  17. Install the bearing cap with sealant applied to the mating areas of the cap and block.
    NOTE
    Keep sealant from the ends of the seal.

  18.  
  19. Torque the rear main bearing cap to specifications.
  20.  
  21. Install the oil pump and oil pan.
  22.  
  23. Fill the engine with engine oil, start the engine and check for leaks.
  24.  
  25. Using the GM diagnostic scan tool or aftermarket equivalent reprogram the necessary systems and components. Be sure to follow the scan tool manufacturer-s directions.
  26.  

Rope Seal

NOTE
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. Before servicing the vehicle, refer to the Precautions Section.
    NOTE
    Disconnecting the negative battery cable on some vehicles may interfere with the functions of the on-board computer systems and may require the computer to undergo a relearning process, once the negative battery cable is reconnected.

  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Raise and safely support the vehicle.
  6.  
  7. Drain the engine oil. Remove the oil pan.
  8.  
  9. Remove the rear main bearing cap.
  10.  
  11. 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.
  12.  
  13. Repeat the procedure on the other end of the seal.

    Click image to see an enlarged view

    Fig. Using the rope seal packing tool-1991-1993



    Click image to see an enlarged view

    Fig. Using the rope seal guide tool-1991-1993



    Click image to see an enlarged view

    Fig. Install the rope seal in the cap using tool J-29590 and cut the seal ends flush with the main cap-1991-1993

  14.  

To install:


NOTE
Be sure to use new fasteners, as required.


NOTE
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread sealer are identified. Do not use paints, lubricants or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners.

  1. 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.
  2.  
  3. Install guide tool J-29114-1 or equivalent, onto the cylinder block.
  4.  
  5. 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.
  6.  
  7. Remove the guide tool.
  8.  
  9. 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.
  10.  
  11. 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.
  12.  
  13. 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.
  14.  
  15. Install all remaining components and inspect for leaks.
  16.  
  17. Using the GM diagnostic scan tool or aftermarket equivalent reprogram the necessary systems and components. Be sure to follow the scan tool manufacturer-s directions.
  18.  

 
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