Rear main seal

[Terrell460]

Soon after i did a ckutch job on my ford the rear main seal began leaking. when i go to napa they have it listed as a two piece and chiltons says its a one piece. any one know which one it raely is?

The truck is a 1990 ford F-250 and has a 460. i just would like to see what it has so i can determine if i can replace the seal with out having to get behind the fltwheel.

 

[LEB Ben]

Two piece...

 

[mrfixit]

The one piece is generally only used on a complete rebuild. The two-piece exists to make for ease rofl2 of replacement.

 

[Terrell460]

Ok cool now to replace it you just remove the oil pan, and loosen the rear cap right?

 

[mrfixit]

You might want to look into a SNEAKY PETE as well

 

[Fellro]

I have pretty decent success getting them to roll out with the crank, basically gotta get it to move, then you can push it on around the crank like a rod bearing. The old cable like that was originally for the old rope seals...

 

[Terrell460]

Ok should i do anything to prep the seal. i remember with my model A i had to soke the seal in oil for a day or so but its an aspestace rope and i imagine this is rubber ore something

 

[mrfixit]

It works with both, but then again, I never tried just rolling it; I'm sure it is a great idea- I just guess I I always worried it might twist or lay sideways where I couldn't see.

 

[Fellro]

No prep, they don't need it. Wouldn't hurt to put a film of oil on the sealing lip, no need for anything more. They have a steel frame inside them, that is why you can push them out like I mention. If they were pure rubber type, they won't move at all, and the cable would be necessary. The frame is dual purpose, it clamps it to the mounting lip, and give the seal a bit of rigidity. The top half is the tricky one, and bottom half is in the main cap and pops out.

I guess I probably never really learned how to use the cable properly, but I also have never actually changed a rope seal either...

 

[mrfixit]

You are so right- I haven't changed one in years and forgot when I was shown the "new" inner-frame ones at a napa store a while back.

 

[LEB Ben]

Remember not to mount either side flush...the top part of the seal should stick out a 1/4" on one side and be recessed a 1/4" on the other...and do the opposite to the bottom side of the seal. There should be some silicone on the ends as well.

 

[smokey]

All good advice above. Very easy to change.
I always tap the upper part of the seal with a punch on the metal insert to break it loose then they normally pull right out. I clamp the vise grips on them and they slide right out.

 

[Terrell460]

Ok im gonna push it as far as i can. i put some rear seal repair aditive in the oil and its working great for a temperary fix. just see how long it lasts tho

 

[Fellro]

I typically use a flat head screw driver to get it going a bit, then it's many times just like Randy said. I have had a few that I had to roll out by turning the crank, but most behave and come out nicely.

 

[Terrell460]

Now im just a little confused on one thing do you have to remove or even loosin the main cap at the back side on the crank shaft or is the seal seperate from that?

 

[Fellro]

The seal is contained inside the rear main cap and rear web, so you have to remove the cap to get to it.

 

[Terrell460]

Ok how high of a torque does the main cap have?

 

[Fellro]

I don't have a book handy to look it up... According to Autozone's website, should be 95-105 foot pounds

 

[Terrell460]

Ok i dont need a new torque wrench. if it leaks again ill just buy a new seal. thanks for the help everyone. ill post on this thread again if i have issues with it.

 

[LEB Ben]

Ok i dont need a new torque wrench. if it leaks again ill just buy a new seal. thanks for the help everyone. ill post on this thread again if i have issues with it.

If you're relying on the additive you will have issues again. Could be in 5 miles or 50,000 miles, it's really a guessing game. The additive causes the seal to swell, but when the effects where off, the seal is 'crushed' further than it was before and comes back with a vengeance. I've used the stuff before in a pinch and it worked for what I needed it for, however, the stuff can and does have a negative impact throughout the engine where you don't need things to swell.