BMW Coupes and Sedans 1970-1988 Repair Guide

Rear Main Seal



See Figure 1

The rear main bearing oil seal can be replaced after the transmission, and clutch/flywheel or the converter/flywheel has been removed from the engine.

Removal and installation, after the seal is exposed, is as follows.

  1. Drain the engine oil and loosen the oil pan bolts. Carefully use a knife to separate the oil pan gasket from the lower surface of the end cover housing.

The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer. You should make every effort to minimize your exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

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Fig. Fig. 1: Remove the retaining bolts on the rear main seal-3 Series model

  1. Remove the 2 rear oil pan bolts.
  3. Remove the bolts around the outside of the cover housing and remove the end cover housing from the engine block. Remove the gasket from the block surface.
  5. Remove the seal from the housing. Coat the sealing lips of the new seal with oil. Install a new seal into the end cover housing with a special seal installer BMW Tool No. 11 1 260 backed up by a mandrel, Tool No. 00 5 500 or equivalent. Press the seal in until it is about 0.039-0.079 inches (1.00-2.00mm) deeper than the standard seal, which was installed flush.
  7. While the cover is off, check the plug in the rear end of the main oil gallery. If the plug shows signs of leakage, replace it with another, coating it with Loctite® 270® or equivalent to keep it in place.
  9. Coat the mating surface between the oil pan and end cover with sealer. Using a new gasket, install the end cover on the engine block and bolt it into place. Be careful to protect the lips of the seal from sharp edges while placing it over the end of the crankshaft. Tighten the grade M6 bolts to 6-7 ft. lbs. (8-0 Nm) and the grade M8 bolts to 15-17 ft. lbs. (20-24 Nm).
  11. Reverse the removal procedure to complete the installation. If the oil pan gasket has been damaged, replace it.