need info on rear main change

Hello to all. As the name implys I am jebears son. He has talked about this site many times and all the people he has gotten to know. A phone call last night let me know that his boat has a rear main that is leaking. This seemed like the best place to get info quick. I'm an experanced mechanic and will have no problem doing the job but the boat is in FL and I'm in TN. want to be ready when it gets here. After that long winded account my question is, can i get by just pulling the tranny or do i have to pull it all? Also, is a 1980 a two piece or one piece seal. that will proberly answer hiw much I pull. Thanks in advance for any replies.

Dennis, I too can't help you on that one but I'd also like to welcome you to the home of a bunch a Correct Craft Fanatics. I had the pleasure of having lunch with them when they stopped on the way to Tenn last summer and hanging out with them at the river run. You've got a great set of parents. Hope we can help you and your Dad out the best we can. I'm sure he'll chime it along with the motor experts to help solve your dilemma. Welcome "Jr."

Dennis,
Welcome! When I first saw your posting nick name I thought your dad had a issue with old man palsy with the extra letters on the tail end of jbear!! I'm glad to find out it's just a simple case of you being his son.

I don't feel pulling the engine will be required. The tail end can be lifted after disconnecting the aft mounts and loosening the forward mounts. If a engine hoist isn't available then a couple small hydraulic bottle jacks can be placed under the exhaust manifolds.

Yes, you might as well put a new seal in the front end of the trans as long as you're in there. Also a good time for a new dampner plate. They are around $100.

Billy's # is 318 386 2825

Welcome Dennis,
If you are your fathers son, you are already a step ahead... John is a good man and you can never know enough of those...

I pulled the motor out of my 80 last year to find my oil leak. I thought that it was the rear seal but turned out to be a pin hole in the rear of the oil pan. My pan was rusting thru and my son welded it until I can get a new one in.
I suspect that Johns is a split seal just as mine is.
Two things to be aware of. Need to make sure that the seal is a reverse rotation seal because the grooves on the new seal need to be going the correct way. Make sure that the grooves on the new seal go the same way as the one you take out.
If the grooves are in the Crank, then the seal will be smooth with no groves.
Sometimes it may take a while to get it. Up to 2 weeks. Skidim has them but I think Reid got one at Advance or Auto Zone in Charlotte.

To replace it, you will need to remove the rear main cap. Then loosen the next 2 main bearing caps to give you some room. The crank needs to lower just a bit to get the old upper seal out. It will not seperate much as the front main and timing chain will still be holding it up. The lower seal half is in the main bearing cap that you removed so it is easy to get out.

If you are lucky, whoever replaced the last seal last left it offset from the main cap gap and you can just pull it out.

If not, to get the upper seal out, you can use a small flat blade screwdriver to ease the old seal away from the block. Then you can use a small punch to work the old seal around the gap. There is a small round piece of steel molded in the seal. use the punch on this piece to tap in. When the other side is sticking out, you can pull it on around and out.

When you put the new seal in, put the tip of the screwdriver against the gap in the block on the inserting side. This keeps the gap edge from cutting away the back of the seal as you work it in.

Then put the rear main cap back on and tighten and torque the mains back down. I tighten them all and then torque, Main cap 3, then 2, then 4.
I hope that this helps a bit..

Again, welcome.

David,

Thanks for the Part # listing.

If you loosen the Rods, then you have to re-torque them. I did not loosen my Rods as you really only have to get the crank pressure off the seal to be able to get it out. There is enough slack that I did not have to loosen the Rods.

I think the torque for the Mains was 95-100 ftlbs and the Rods were 40-45. But it has been a year since I did it.

This is a good online book....
How to rebuild your Ford V8

First let me say, WOW. I didn't exepct such a responce so fast with so much info. You guys really give a warm welcome. I had to go out of town Monday morning and haven't had a chance to check e-mail till just now.
But anyway. Down to business. I did get a chance to go down to the garage and look at the standard truck 351 I have on a stand. Everyone has one in their garage, right. sits right next to the big block. OK mabey I'm not normal. anyway, That one takes a one piece seal. Ive never had a 351 marine apart, but i have changed rear main seals without tacking the caps off. I no longer run my own auto repair garage, so I'll be doining this in the gravel drive. Suporting the back of the motor and pulling the trans sounds much easier. By the way. Mechanical ability seems to have skiped a generation. Dad will have the job of watching and running to the tool box so I don't have to keep getting out of the boat.

After looking through manuels and making phone calls I realized I was comparing a 1980 motor to a 1989 motor. Different rear mains.I stand corrected. parts lists are coming together, plan comming together, Dads roll in all of this might be to just watch me work and pay for it.I know from past projects that he is good at both of these.

Thanks to all for the warm C/CFAN welcome for Dennis. I think Tim Morfoot has it right "best bunch of friends a guy could ask for"....

As we all know on here I am a little challenged under the motor box. Thats why it has always been cool to have a son that could take apart anything, figure out how it worked, and put it back together with no pieces left over. Used to drive his Mom crazy when he was a kid. He always had something of hers up in the bedroom "working" on it. Ran a bike shop outa our garage before he went in the Navy. Worked on some big stuff there before getting out and running his own garage. Bet he will relate well with the boat dr and eric.

Sounds like you guys have him goin' in the right direction. I am gonna have fun running to the tool box and the cooler.

Thanks again guys...what a great bunch of friends!

john