1968 300 Rear Main Seal Leak

[mgm1986]

Fellow enthusiasts, looking for input from those who have done it before. I have been driving my 300 for probably a hundred or so miles now, just local back road running. I am very happy how well it runs and very surprised how much gas it burns cause I can't stay out of the secondaries!

What I don't love is the rear main seal is leaking. I can confirm it is not the oil pressure switch or the valve covers which leads me to the rear main seal. I have seen a few videos, read through the FSM and crawled under the car to inspect. I am not looking forward to this task but I also hate leaving oil everywhere I park. Although the undercarriage is mostly rust free being so coated in oil.

Remove the steering linkage to get the oil pan off (half the pan bolts aren't even screwed all the way), remove the two bolts holding the cap on and work out the old seal and replace with new.

Is it feasible to do this job without a lift laying under the car or am I going to need better access to do it the right way?

440BB, no idea if it's original to the car. Thanks in advance for your sage advice!

 

[commando1]

I know people who have rebuilt their engines lying on their back in February. Could I do it? Absolutely no way. For me the engine needs to be out of the car or up on the lift.
I suggest unbolting the engine mounts, raise the engine and pulling the entire pan off. I don't see the need to touch the steering gear at all.
After all is said and done, it might still leak, lol.

 

[3175375]

I have replaced the rear main seal in our 65 Ranchero. It wasn’t too bad. I botched the first seal, so I had to replace it and ended up boogering the oil pan gasket on removing it, so I had to replace that too. Nonetheless, with patience and attention to detail, I am confident that you can do this.

 

[mgm1986]

It seems like one of those jobs that is only difficult because you have to remove so much other stuff. And if it leaks you're pulling the oil pan off again.

I'll plan on getting it as high off the ground as I can and take a crack at it.

Thanks for the motivation

 

[mgm1986]

I know people who have rebuilt their engines lying on their back in February. Could I do it? Absolutely no way. For me the engine needs to be out of the car or up on the lift.
I suggest unbolting the engine mounts, raise the engine and pulling the entire pan off. I don't see the need to touch the steering gear at all.
After all is said and done, it might still leak, lol.

I will definitely remove the entire pan but I'm thinking the steering linkage is gonna need to get taken apart to get the pan off. If I could jack the engine high enough to get the pan off that would be awesome but I just did the motor mounts and it didn't look like an option.

 

[CBODY67]

You might check the Chrysler factory service manual to see about removing the oil pan "in car". Seems like there is something about manually turning the engine to get crankshaft counterweights out of the way?

Work safely!
CBODY67

 

[65Port]

My advice is to drive it some more and keep track of the leak amount. My 383 will leak a tiny bit (2-3 small drops) after a winter slumber then stop completely.. Seeing you have only driven 100 miles, maybe give it a little more time/mileage to see what you are up against. I've seen too many people go nuts replacing rear main seals and then... drip drip.. (as commando said above). You might get lucky but.. are you feeling lucky?

Good luck..

 

[mgm1986]

Finally decided to tackle the rear main seal leak. I removed the steering linkage and was able to lift the engine a couple inches to remove the oil pan.

After removing the rear main seal retainer I found the bolts used were too long which cracked the retainer on both sides. Now I am trying to figure out how to remove the old rope seal from the engine. Doing some research it seems I may need to loosen some of the caps to lower the crank but I am going to ask here before I start loosening those bolts.

I have tried to tap it through with a dowel. I also tried using a screw to pull it out (like a corkscrew). My next thought seemed dangerous to try; set the thing on fire and let it burn itself out!

Any suggestions or wisdom on removing an old rope seal while the engine is still in the car?

 

[3175375]

I found this post:

Help Removing a Rear Main Rope Seal - Ford Truck Enthusiasts Forums

It references a sneaky Pete:

Lisle 27000 Sneaky Pete | Removes and Installs Upper Rear Main Seals | eBay


Let us know how it turns out…

 

[mgm1986]

Dang, guess my google search skills need work! I ordered the sneaky pete, will be here in a couple of weeks. Will report back with my results. Cleaning it all up once the seal is out will be another fun challenge!

 

[mgm1986]

Unfortunately the Sneaky Pete did not work to remove the upper half of the rear main seal (it is a rope seal). It would only screw in about half way before seemingly bottoming out. I removed the rear crank cap to improve access but still unable to get the old seal out.

I am now planning to remove the engine and transmission to finish the job. I half everything except the drive shaft and exhaust manifolds disconnected. Once those are apart it looks like it will slide out fairly easily.

With the engine out I am going to give the engine bay a good clean, re-gasket the engine and give it a coat of paint. My first engine removal so hopefully it goes back together as easy as it comes apart!

 

[3175375]

Unfortunately the Sneaky Pete did not work to remove the upper half of the rear main seal (it is a rope seal). It would only screw in about half way before seemingly bottoming out. I removed the rear crank cap to improve access but still unable to get the old seal out.

I am now planning to remove the engine and transmission to finish the job. I half everything except the drive shaft and exhaust manifolds disconnected. Once those are apart it looks like it will slide out fairly easily.

With the engine out I am going to give the engine bay a good clean, re-gasket the engine and give it a coat of paint. My first engine removal so hopefully it goes back together as easy as it comes apart!

Sorry to hear about that. You’ll get there.

 

[detmatt]

I’d replace the rope seal with another rope seal. I can almost guarantee a lip seal will leak as much or worse…

 

[mgm1986]

Finally had time this morning to pull the engine. I did not remove the transmission cross member but I should have and will before dropping it back in. With a little luck I'll have everything cleaned up and the front suspension rebuilt before spring.