Jeep 4621939AB Seal-Rear Main CRANKSHAFT

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Do not rotate the camshaft(s) or crankshaft when the timing belt is removed or damage to the engine may occur. Begin by removing the timing belt. Measure the installed depth of the crankshaft sprocket in relation to the end of the crankshaft or the front of the engine, as this is important for proper timing belt alignment. Use a bolt-type gear puller to remove the crankshaft sprocket, and then take out the Woodruff key. Wrap the tip of a small screwdriver with tape and, working from below the right inner fender, pry the seal out of its bore, taking care to avoid damaging the oil pump assembly, crankshaft, and seal bore. Clean and inspect the seal bore and sealing surface on the crankshaft, removing minor imperfections with emery cloth; if a groove is worn in the sealing surface, a new seal may not stop the leak. Lubricate the new seal with engine oil and drive it into place using a hammer and an appropriately sized socket. The remaining steps involve reversing the removal process. The crankshaft sprocket depth is set to a factory specification to ensure correct timing belt alignment. If available, use the special factory tool with a built-in setting to install the crankshaft sprocket or carefully push it on until it is in the same position as previously measured. Position the crankshaft sprocket with the word FRONT facing out before installing it onto the crankshaft. Finally, reinstall the timing belt(s) and covers, then run the engine and check for oil leaks.

The one-piece rear Crankshaft Seal is pressed into a bore machined into the rear main bearing cap and engine block. Begin by removing the trans axle, clutch components if equipped, and the flywheel or drive plate. Ensure the Crankshaft Seal is installed flush with the outer surface of the block, and carefully pry out the old seal using a 3/16-inch flat blade screwdriver, taking care not to nick or scratch the crankshaft or seal bore. To prevent an oil leak after installing the new seal, avoid scratching or damaging the crankshaft sealing surface or the bore in the engine block. Clean the crankshaft and seal bore thoroughly, degreasing these areas with a rag soaked in lacquer thinner or acetone, and do not lubricate the lip or outer diameter of the new seal as it must be installed as it comes from the manufacturer. Position the new seal onto the crankshaft, ensuring that if marked, the words THIS SIDE OUT face out toward the rear of the engine. Using an appropriately sized driver and pilot tool, drive the seal into the cylinder block until it is flush with the outer surface; avoid driving it past flush to prevent an oil leak. The remainder of the installation follows the reverse order of removal.

Thoroughly clean the seal bore in the seal housing with a shop towel, removing all traces of oil and dirt.

The one-piece rear main oil seal is designed to prevent oil leaks from the rear main bearing cap and engine block.

The first step is to remove the timing belt.

Drive the seal into place using a seal driver or a large deep socket and gently tap it with a hammer, ensuring the seal enters the bore squarely.

Begin by removing the driveplate, ensuring that the oil seal is installed flush with the outer surface of the block.

Thoroughly clean the crankshaft and seal bore in the block, de-greasing them with a rag soaked in lacquer thinner or acetone.

Install the Woodruff key and the crankshaft timing belt sprocket with the word "FRONT" facing out on the crankshaft.

Remove the crankshaft pulley.

Carefully pry the oil seal out of the cover with a seal puller or a large screwdriver, taking care not to damage the crankshaft surface.

Check the engine oil level and add oil if necessary. Start the engine, let it warm up, and check for leaks.

Lay the retainer on a clean, flat surface and carefully drive in the seal with a block of wood and a hammer.

Bolt the housing to the block and tighten the housing bolts gradually until they are all snug.

You should be able to slide the crankshaft sprocket off by hand. If it is stuck, use two screwdrivers to carefully pry it off.

Position the crankshaft sprocket with the word "FRONT" facing out and install it onto the crankshaft.