Chevrolet Repair: main bearing, main bearing cap, main bearings

Question
do they make a tool to replace main bearings in my 4 cyl. s-10 pickup? i only need the rear and dont really want to pull the enjine to do this .  i am an above knowledgeable mechanic and can do what has to be done.thank you. george

Answer
Hi George,

They may make a tool to do this, but I never used one.  Are you sure the rear main seal is not associated with the main bearing cap?  If so, is yours a split seal, or a solid one.  If solid, are you going to seal up when done with the bearing cap?  Sometimes these rear seals are rope.  

If you decide to change the seal, you need to back off the transmission, or disconnect the engine.  You won't have to take the engine all the way out, but it will hang from a puller so you have enough room to get at the seal.  Probably, easier to pull the trans, when you consider the exhaust, radiator, pullys and accessories, and everything.  

If you decide to not change the rear main seal:

To change the main bearing(s) without pulling the motor, you have to pull the oil pan off.  You probably have to raise the motor up, by pulling the motor mount bolts and using a floor jack under the oil pan...piece of wood between the jack and pan for cushion.  Once the engine is raised up as far as it will go, put 2x4's between the mounts on the motor and the other half left on the frame.  Drop the motor onto these pieces of wood and remove the jack.  

To pull the pan, you need to move everything in the way (exhaust, front drive shaft if there is one, starter, support brackets, etc).  To drop the pan, you need to disconnect the oil pump.  Drop the pan from the engine, leaving enough room for you to unbolt the pump.  Drop the pump into the pan and pull them out together.  

Loosen all of the main bearing caps.  Remove the desired ones.   Once all the caps are loose, the rods will hold the crank, but allow it to drop slightly.  The old and new bearings have a notch in them.  Push the upper bearing out by pressing on the edge without the notch.  It will start feeding around the crank until it is 180 degrees around.  Now it should just drop off.  Put the new one in place the same way.  Start the side without the notch in, and feed until the notch seats in the hole.  Then replace the one in the cap, and reinstall the cap.  Once all the ones you want to replace are done (I would do them all), re-torque the bolts.  

Hope this helps.

C J S