Rear crank seal replacement ??

Small Block Mopar Engine

  1. steve801

    steve801 Active Member

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    I was hoping you guys could give me a little education on how to replace the rear crank seal on a 318. The motor is out of the car, but the crank is staying in.
     
  2. 340sFastback

    340sFastback Well-Known Member

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    If you take off the rear main cap the seal that is in the block is most likely rubber and all you have to do is press on one side and it will pop out the other. Grab it with needle nose pliers and pull it out. The new seal will slip right back into the block, lip facing in, and put a light amount of oil on the seal where it hits the crank or it will burn up when you start the engine.

    Clean main cap and block sufaces with clean paper towels and Brake Parts Cleaner (Walmart or auto parts store). Get sufaces 100% clean. Put thin film of Permatex RVT sealers on the cap to block suface or it will leak. I use Felpro rear main oil seals and no leaks here.

    Lip facing in don't forget or you will be doing it again. Light oil on lip where it hits crank. Dab, very small dab, of sealer where the two halves meet. Make sure its a small enough dab is won't squish onto the crank, just a little thin film is all you need. You don't want any sealer anywhere close to the crank to seal surfaces.

    Make sure you put a bead of sealer in the corners where the oil pan gaskets meet and take your time.

    If done right it won't leak a drop.
     
  3. steve801

    steve801 Active Member

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    many thanks for getting the cob webs out of my head...a great summation! with regards to the oil pan gasket...mine always seem to leak...have you ever tried using Locktite sealant instead of a gasket?
     
  4. 340sFastback

    340sFastback Well-Known Member

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    The way I did mine is I glue the side pieces to the engine block with black 3M Weatherstrip adheasive, just a thin bead of the adheasive, press on block and let it dry. Then I do a thin film of Permatex Black RTV sealer on the top of those side pieces and let that set up for 10 minutes. Then thin film of RTV sealer on the end pan and block surfaces. A bead of sealer in each corner. Carefully lower pan into place and slowly cross tighten pan down.

    There was a thread on oil pan gaskets recently and one person said they used a thick bead of RTV instead of the end gaskets. I think that would work well assuming you get the bead the right thickness. Put pan up and eye it up first. I do my intakes like that, no gaskets on the ends and will probably do my oil pan like that next time.

    I use Felpro cork/rubber (side pieces) gaskets and have had good luck on getting it 100% sealed up. You have to take your time and go slow. And do not over tighten the pan.
     
  5. TheMattMobile

    TheMattMobile 74 Dart Swinger

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    I tried that trick, but tapping on the one side of the seal I can't get the other one to slide up. Any ideas there?
     
  6. krazykuda

    krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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    If you remove the crank, it is much easier.
     
  7. TheMattMobile

    TheMattMobile 74 Dart Swinger

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    I was trying not to remove the timing chain and all but that seems to be the way I am going to have to do it.
     
  8. my5thmopar

    my5thmopar Life Long MOPAR Owner FABO Gold Member

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    Timing chain??That is for the front seal not the rear crank seal as you state. I did mine the other day. Like it was said here. Remove the rear main cap. Push one side enough to grab with needle nose pliers. If that doesn't work you may have to use a screw to "gently" thread into the end of the seal and pull it out. There is a tool made specifically for this. Be careful.

    Craig
     
  9. TheMattMobile

    TheMattMobile 74 Dart Swinger

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    For whatever reason that trick didn't work... The seal was just falling apart and wasn't staying together enough to push it through. I ended up having to pull the timing chain and the crank.
     
  10. my5thmopar

    my5thmopar Life Long MOPAR Owner FABO Gold Member

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    Too bad!! So I'm guessing it was the rope type seal. That is what 35-40 years in a engine will do for ya. But glad to hear you got a fix.

    Craig
     
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