Mazda Trucks 1972-1986 Repair Guide

Rear Main Oil Seal

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REPLACEMENT 1,586cc, 1,796cc and 1,970cc Engines



See Figures 1 and 2

Click image to see an enlarged view

Fig. Fig. 1: Removing the rear main seal on the 1,586cc, 1,796cc and 1,970cc engines using sheet metal screwspry outward on both screws at the same time to remove the seal



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Fig. Fig. 2: Installing the rear main seal on 1,586cc, 1,796, and 1,970cc engines using a seal installer tool

If the rear main oil seal is being replaced independently of any other parts, it can be done with the engine in place. If the rear main oil seal and the rear main bearing are being replaced, together, the engine must be removed from the truck.

  1. Remove the transmission.
  2.  
  3. On trucks with a manual transmission, remove the clutch disc, pressure plate and flywheel. On trucks with an automatic transmission, remove the drive plate.
  4.  
  5. Using an awl, punch two holes in the crankshaft rear oil seal. They should be punched on opposite sides of the crankshaft, just above the bearing cap-to-cylinder block split line.
  6.  
  7. Install a sheet metal screw in each hole. Pry against both screws at the same time to remove the oil seal. Do not scratch the oil seal surface on the crankshaft.
  8.  
  9. Clean the oil recess in the cylinder block and bearing cap. Clean the oil seal surface on the crankshaft.
  10.  
  11. Coat the oil seal surfaces with oil. Coat the oil surface and the seal surface on the crankshaft with Lubriplate. Install the oil seal and be sure that it is not cocked. Be sure that the seal surface was not damaged.
  12.  
  13. Install the flywheel. Coat the threads of the flywheel or drive plate attaching bolts with oil resistant sealer. Torque the bolts to specifications in sequence across from each other.

    Flywheel:
     

  14.  

Gasoline engine 115-120 ft. lbs.

Diesel engine100-140 ft. lbs.



Drive plate: 60-69 ft. lbs.
 

  1. Install the clutch, pressure plate and transmission.
  2.  

1,998cc Engine See Figures 3 and 4



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Fig. Fig. 3: Installing the rear main seal on a 1,998cc engine using a press



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Fig. Fig. 4: View of the 1,998cc engine rear cover installation

  1. Remove the transmission.
  2.  
  3. Remove the clutch assembly.
  4.  
  5. Remove the flywheel.
  6.  
  7. Remove the end plate.
  8.  
  9. The seal is located in the rear cover. Remove the rear cover. Discard the gasket.
  10.  
  11. Drive the old seal from the rear cover.
  12.  
  13. Apply clean engine oil to the outer rim of the new seal and the seal bore in the rear cover. Press the new seal into place.
  14.  
  15. Coat the seal lip with clean engine oil. Install the rear cover and new gasket. Torque the bolts to 72-102 in. lbs. (6-8.5 ft. lbs.).
  16.  
  17. Using a sharp knife, cut away the part of the gasket that projects below the rear cover.
  18.  
  19. Install the end plate. Torque the bolts to 14-22 ft. lbs.
  20.  
  21. Install the flywheel.
  22.  
  23. Install the clutch assembly. See General Information And Maintenance .
  24.  
  25. Install the transmission.
  26.  

2,209cc Diesel Engine

  1. Remove the transmission.
  2.  
  3. Remove the clutch assembly.
  4.  
  5. Remove the flywheel.
  6.  
  7. Remove the rear main seal housing.
  8.  
  9. Drive the old seal from the housing.
  10.  
  11. Clean the housing bore thoroughly.
  12.  
  13. Coat the outer edge of the new seal with gasket sealer.
  14.  
  15. Drive the new seal into the housing until it bottoms.
  16.  
  17. Coat the seal lip with clean engine oil and install the housing onto the engine. Torque the bolts, in a criss-cross pattern, to 10-14 ft. lbs.
  18.  
  19. Install all other parts in reverse of removal.
  20.