GM Bonneville/Eighty Eight/LeSabre 1986-1999

Rear Main Oil Seal

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REMOVAL & INSTALLATION



1987-90 Vehicles
ROPE SEAL REPAIR

See Figures 1, 2 and 3

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the vehicle safely.
  4.  
  5. Drain the engine oil into a suitable container.
  6.  
  7. Remove the oil pan, as outlined earlier in this section.
  8.  
  9. Remove the rear main bearing cap. Remove the oil seal from the bearing cap.
  10.  
  11. Insert packing tool J-21526-2 or equivalent against one end of the seal in the cylinder block. Pack the old seal in until it is tight. Pack the other end of seal in the same manner.
  12.  



Click image to see an enlarged view

Fig. Fig. 1: Use a special tool to pack the seal into the block

  1. Measure the amount the seal was driven up into the block on one side and add approximately 1 / 16 inch (2mm). With a single edge razor blade, cut this amount off of the old lower seal. The bearing cap can be used as a holding fixture.
  2.  

A small amount of oil on the pieces of seal may be helpful when packing into the cylinder block.

  1. Install the packing guide tool J-21526-1 or equivalent, onto the cylinder block.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: Installed view of the packing guide tool

  1. Using the packing tool, work the short pieces of the seal into the guide tool and pack into the cylinder block, until the tool hits the built-in stop. Repeat this step on the other side.
  2.  



Click image to see an enlarged view

Fig. Fig. 3: Pack the short seal pieces into the block with the tool, until the tool hits the built-in stop

  1. Remove the guide tool.
  2.  
  3. Install a new rope seal in the bearing cap and install the cap. Tighten the retaining bolts to 90 ft. lbs. (122 ft. lbs. )
  4.  
  5. Install the oil pan, then carefully lower the vehicle.
  6.  
  7. Fill the crankcase with the proper type and amount of engine oil.
  8.  
  9. Connect the negative battery cable.
  10.  

ROPE HALF-SEAL REPLACEMENT

See Figures 4 and 5

  1. Remove the engine from the vehicle.
  2.  
  3. Remove the oil pan. Remove the rear main bearing cap-to-engine bolts and the cap.
  4.  
  5. Remove the old seal from the bearing cap. Clean the remains of sealer and adhesive from the upper and lower bearing groove, and clean the mating surfaces of the bearing cap.
  6.  

To install:
  1. Using suitable sealant, apply it to the main bearing cap seal groove and, then perform the following steps within 1 minute.
  2.  
  3. Using a new rope seal and a wooden dowel or hammer handle, roll the new seal into the cap so both ends project above the parting surface of the cap; force the seal into the groove by rubbing it down, until the seal projects above the groove not more than 1 / 16 inch.
  4.  



Click image to see an enlarged view

Fig. Fig. 4: Use a wooden dowel or equivalent tool to seat the seal in the cap

  1. Using a sharp razor blade, cut the ends off flush with the surface of the cap.
  2.  
  3. Using chassis grease, apply a thin coat to the seals surface.
  4.  
  5. To install the neoprene sealing strips (side seals), perform the following procedures:
  6.  
  7. Using light oil or kerosene, soak the strips for 5 minutes.
  8.  

The neoprene composition seals will swell up once exposed to the oil and heat. It is normal for the seals to leak for a short time, until they become properly seated. The seals must not be cut to fit.

  1. Place the sealing strips in the grooves on the sides of the bearing cap.
  2.  
  3. Apply a suitable sealer it to the main bearing cap mating surface; do not apply sealer to the bolt holes.
  4.  



Click image to see an enlarged view

Fig. Fig. 5: Apply sealer sparingly to the areas shown, but avoid the bolt threads

  1. Install the main bearing cap. Torque the main bearing cap-to-engine bolts to 90 ft. lbs. (122 Nm).
  2.  
  3. Install the oil pan.
  4.  
  5. Lower the vehicle.
  6.  
  7. Refill the crankcase.
  8.  
  9. The engine must be operated at low rpm when first started, after a new seal is installed.
  10.  

1991-99 3.8L (VIN C, L and 1) Engine

ONE PIECE LIP-TYPE SEAL

See Figures 6, 7 and 8

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Remove the transaxle, as outlined in Drive Train of this repair guide.
  6.  
  7. Remove the flywheel, as outlined later in this section.
  8.  
  9. Confirm that the rear main seal is leaking.
  10.  


WARNING
Use care when prying out the seal to avoid damage to the OD and chamfer of the crankshaft.

  1. Insert a suitable prying tool through the dust lip at the angle shown in the accompanying figure. Pry the seal out by moving the handle of the tool toward the end of the crankshaft pilot. Repeat the process, as required, around the seal until it is removed.
  2.  



Click image to see an enlarged view

Fig. Fig. 6: Insert a small prytool through the rear main seal dust lip at the angle shown

To install:
  1. Apply engine oil to the ID and OD of the new seal. Slide the new seal over the mandrel until the back of the seal bottoms squarely against the collar of the tool.
  2.  



Click image to see an enlarged view

Fig. Fig. 7: Slide a new, lubricated seal over the mandrel of the tool until the back of the seal bottoms squarely against the collar of the tool

  1. Align the dowel pin of the installation tool with the dowel pin in the crankshaft and attach the tool to the crankshaft by hand or by tightening the attaching screw to 60 inch lbs. (5 Nm).
  2.  



Click image to see an enlarged view

Fig. Fig. 8: Exploded view of the rear main seal and installation tool

  1. Turn the T-handle of the tool so the collar pushes the seal into the bore. Continue turning until the collar is tight against the case. This will ensure that the seal is seated properly.
  2.  
  3. Loosen the T-handle of the tool until it comes to a stop. This will ensure that the collar will be in the proper position for install another new seal.
  4.  
  5. Remove the attaching screws.
  6.  
  7. Install the flywheel, as outlined later this section.
  8.  
  9. Install the transaxle, as outlined in Drive Train .
  10.  
  11. Carefully lower the vehicle, then connect the negative battery cable.
  12.  

1995-99 3.8L (VIN K) Engine

REAR MAIN SEAL CARRIER

See Figure 9

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle. Drain the engine oil into a suitable container.
  4.  
  5. Remove the transaxle, as outlined in Drive Train of this repair guide.
  6.  
  7. Remove the flywheel, as outlined later in this section.
  8.  
  9. Remove the oil pan.
  10.  
  11. Unfasten the rear main seal carrier attaching bolts.
  12.  
  13. Remove the rear main seal carrier plate.
  14.  
  15. Carefully pry the rear main seal from the carrier.
  16.  



Click image to see an enlarged view

Fig. Fig. 9: The 3.8L (VIN K) engine uses a rear main seal carrier plate

To install:

Proper alignment of the plate is crucial to the sealability of the rear main seal and oil pan. Take care when installing the plate to ensure the plate is properly aligned. In order to properly align the plate, use a suitable rear cover aligning tool, J 41349 or equivalent installed to the rear of the crankshaft. Check that you have equal distance between each side of the plate crank seal surface. Failure to do this may result in oil leaks.

  1. Make sure the oil seal is removed from the housing.
  2.  
  3. Install the housing and finger-tighten all of the bolt (loose enough to adjust the housing) to hold the housing in place.
  4.  
  5. Wipe a thin film of clean engine oil on both sides of the rear cover alignment tool to help in installing and removing from the crankshaft.
  6.  
  7. Install the rear cover alignment tool over the crankshaft; twisting or turning the tool helps in sliding it from the crankshaft.
  8.  
  9. Install the housing bolts and tighten to 22 ft. lbs. (30 Nm). Remove the alignment tool.
  10.  
  11. Place straight edge on the cylinder block oil pan flange and the housing flange. Use a feeler gauge to make sure there is no more than 0.004 in. step, high or low. If beyond specifications, repeat the preceding 4 steps and measure again. If excessive clearance is still present, replace the housing.
  12.  
  13. Install a new oil seal using rear main installer tool, J 38196 or equivalent.
  14.  
  15. Install the oil pan.
  16.  
  17. Install the flywheel.
  18.  
  19. Install the transaxle, as outlined in Drive Train .
  20.  
  21. Carefully lower the vehicle, then connect the negative battery cable.
  22.  

 
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