I have searched for this topic and read a couple of manuals, and I'm just wondering what you all do to keep your 2 piece rear main seals from leaking. I have had my motor in for less than 1000 miles and forgot to put on RTV but did offset the seal. Now I have a leak so I just pulled the motor and tranny and bought a new RMS along with a new one-piece oil pan gasket. Also I am not wanting to loosen all of the mains other that the rear main, but if there is a risk to damaging the seal and having another leak then I will surely do it. Any and all advice is appreciated.

Drew

 

If by chance it is a 400 block it requires a special seal for blocks that were align honed or align bored. The part number escapes me. If it is a 350 type block I usuall offset with a small smear of ultra copper on the seal edges and a thin smear on the main cap. Very thin though. Thin enough to see thru.

 

Assemble it correctly.

The factory, and lots of the ret of us, have been doing it for many decades now.

The 3 most common mistakes are to glob a bunch of sealer on teh back side of the seal; to just jam the seal straight down onto the place it goes; and to put it in backwards (such that it wipes the oil out of the block, instead of back into the crankcase). Avoid those 3, and then stagger the ends so that they don't line up with the block, and put a bit of sealer on the rear main cap register surface where the pressurized passage goes from the cap to the block, and you'll have much better odds.

 

He pretty much nailed it, I use (old school) Aviation Permatex.
Here's another trick. If the crank has been cut excessively, slide a piece of tie-wrap between the seal and the block.
Sounds crude, works like a champ.
I BS though not

 

Ok, so I'm sure that my leak was caused by my not putting any sealer of any kind on the rear main when I assembled the motor, and from what I'm hearing the exact type of sealer doesn't really matter as long as there is sealer in the right spot. My other question is how can I (if even possible) install the seal with the crank in? Must I remove all of the main and rod caps to?(really dont want to unless its the only way) thanks again.

 

Pop off the main cap, push/tap the old seal out AROUND the crank (with a drift, screwdriver, whatever) just enough to grab it with pliers and yank it the rest of the way out, basically sliding it around the crank. Reinstall the new one in a similar manner- sliding it into the receiver groove in the block by wrapping it around the crank and sliding it in there around the crank- it'll take some "persuasion" but not so much as to distort the seal's shell. Lots of oil on the seal helps, obviously.

Do what RB said about RTV on the main cap saddle surface. I TINY little bit. Just a paper-thin smear, not big globs.