I was wondering how hard would it be and what would it take to change out a rear main seal in my 89 f150.

 

If you are OK with removing the trans and flywheel, then the rest is easy. A helper is recommended for the trans R&R.

 

for sure have some help on the trans. as they are heavy and it's unsafe to do it by yourself. The rear main seal itself is easy to replace once the tranny and flywheel are out of the way.

 

As I Will Be Doing This My Self, And Of Course With Help, But What I Need To Know Is Do I Just Take The Tranny Loose And Drop It And Then Replace It, Or Will I Need To Mess With The Motor.

 

Once the flywheel is off, you will be looking at the flange of the crank to which the flywheel is bolted. The seal is one piece like a big wheel bearing seal, and is pressed in to the block, surrounding the seal surface behind the flange. Observe how it is oriented, and how it is pressed in about flush with the block.

Clean everything off so you can see what's what. Drill a small hole into the metal part of the seal so you can screw a small sheet metal screw in there. Then with a pair of vice grips or something, pull the seal out. It will be tight. Be careful to drill straight so you don't nick the crank. You need to do this because there is really no other way to get a purchase on the thing. I don't recommend jamming a screwdriver between the seal body and the block.

Clean it up again, and then get some fine emery cloth at the hardware store. Cut a strip, and polish the seal surface on the crankshaft. If there are grooves deep enough to hang up a fingernail, this may take a while. Don't worry too much about getting it perfect, but do a good job.

Make sure everything is clean before re-installation. I like to put a thin coating of RTV around the outside of the metal seal body for extra sealing, but it's probably overkill. Do be sure and put a light coating of engine oil on the rubber surface of the seal so it doesn't run dry the first time you start the engine.

Now you need to press the seal in so it it is nice a square to the block. This can be done carefully with a plastic mallet or a small ball peen hammer if you are gentle. Try not to dent the metal seal body as you drive it home. Just work carefully, gently tapping all the way around until it is seated.

Now except for the little task of reinstalling the tranny etc, you are good to go.

 

I do it almost the same exact way but I do use a small screwdriver to remove the old seal but with caution not to marr the crank flange. Hope that answers your question. do make sure that the surface is clean before installing the new seal.

 

I Appreciate All Of Your Help, Please Dont Go Anywhere Because I Am 100% Positive That I Will Need More Answers After I Get This Project Started.