rear main seal fel pro 40240

Engine, Trans & Driveline

  1. velrob

    velrob Well-Known Member

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    383 motor rear Main seals and side seals

    I bought a fel pro kit 40240

    the half seal is are black and the side seals are blue

    should I be using silicone sealer on both seals or install dry? of course I will greasing where the crank turns

    thanks
     
  2. Schober Motorsports

    Schober Motorsports Well-Known Member

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    Usually I put a little dab on the ends of the half seal and fill up the blue strips with silicone once installed. Then do a touch up on the bellhousing side and its good to go. Really hard to seal up the rear main on these big blocks 100%, but just take your time. Before installing the blue strips I soaked them in diesel fuel to make them easier to slide in when installing the rear main seal retainer. Good luck!
     
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    • lewtot184

      lewtot184 Well-Known Member

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      the last blue side seals I put in were very difficult to install. what I ended up doing was siliconing the sides to the retainer and then put the retainer in a vise with some mild pressure on the side seals. left it overnight, and then installed with some silicone on the block were the side seals locate. it was a snug fit but ended up good. I like the blues but they can be very tight.
       
    • 65-440

      65-440 Well-Known Member

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      You should throw those seals in the garbage ..... call Todd at marsh performance and order the felpro high vacuum seal, much better .... unless you can find that felpro kit local, will be an orange/ brownish color. That black seal is a piece of shit ....
       
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      • 69Bee

        69Bee FBBO Gold Member FBBO Gold Member

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        I just used this in a full set, and if I offered any advice, use a file to slightly chamfer the block leading edge where the seal would be shaved putting it in. I did this, and it installed perfectly. Use some assembly lube or oil on the seals and you should have no issues.
         
      • Yatzee

        Yatzee Well-Known Member

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        I used a Marsh seal as well but here's something I did that I doubted would work but came out perfect first time - no leak. The joint in the split seal is vertical, not horizontal, that's right verticle. The ends of the seal had just a touch of The Right Stuff smeared on them and slid into place after putting a light coat of oil on the machine ways sides and bottom of the holdr and block. As I see it doing it this way ensures the ends of the seal are pressed together when the cap is installed and the joint in the seal becomes captured in the grooves. The normal way means that there are sealing points from the seal right out to the edge of the seal block on a horizontal plane. The side seals were left out completely and injected with the same product until it oozed out a small groove I filed in the bottom of the holder leading to the outer side only of the cap. Not a drop of oil has leaked out the rear of the block.
         
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        • dangina

          dangina Well-Known Member

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          where do you buy the marsh seal?!
           
        • velrob

          velrob Well-Known Member

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          hey 65-440 do you mean these?

          https://www.summitracing.com/int/parts/fel-2947/overview/make/chrysler

          if it works better then ill pick that up for sure

          worth the 30 bucks for no pains later
           
        • Cornpatch MO

          Cornpatch MO Well-Known Member

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          I am glad your seal worked out for you, but I would not fill the grooves in the sides with silicone. Maybe OK if the engine is not started until silicone completly cures. I had a certified mechanic install my Hughes seal and retainer kit. I told him to do it exactly the way the instructions say. After done, he said he filled the grooves with silicone instaed of the seals " always works" He had to do it over again on his dime and new pan gasket out of his pocket............................................MO
           
        • 65-440

          65-440 Well-Known Member

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          Yes, that's the one. They don't show the side seals though, mine came with red seals from superformance. But honestly, I think the blue side seals you already have would be just fine, it's that black lip seal that sucks. My experience, just went through this last year on my 383. Fresh build, I'll admit I messed up the rear main when I put the engine together. Way too much RTV in the retainer groove, it got on the lip seal and dried. The engine sat for about 2 weeks before I fired it. Tore the lip on the seal. It leaked, not terrible but it leaked. I replaced it with the standard black seal and it poured out. Much worse than the damaged seal. I called Todd at marsh performance and talked to my local mopar engine builder and they both said they've never had luck with those black seals, great, wish I'd known this before hand ! I ordered the orange felpro kit, a year later and still dry!
          It's obviously your car, your decision. Everyone's been there, done that. But I will never install one of those black seals again ......
           
        • 65-440

          65-440 Well-Known Member

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          The seal kit is $18 on his website, call and order. He ships same day
           
        • velrob

          velrob Well-Known Member

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          I guess the high vacuum seal needs to be installed dry? I'm from Canada so I'm trying to find it locally but I'll call Todd and see

          BTW what is this thing for?

          firefox_2017-11-30_09-03-00.jpg
           
          Last edited: Nov 30, 2017
        • 65-440

          65-440 Well-Known Member

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          I put a thin film of ultra black RTV on the back side of the 2 halves, put a good coat of assy lube on the crank, RTV on both sides of the side seals. Not a hard job at all, although I did take the pan down the day before so I would not get rained on by oil drips !
           
        • 65-440

          65-440 Well-Known Member

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          No clue what that thing is in that picture
           
        • velrob

          velrob Well-Known Member

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          rofl alright thanks alot.

          thankfully my motor is out so no dripping oil :).

          do i apply any RTV on where the cap seats on the block? at the very bottom around the bolt holes i mean.

          do i apply any thread sealer on the bolts?

          looks like people in this thread had some trouble with the side seals. so you applied RTV on both sides of side seals and just slid the cap in with no troubles?
           
        • lewtot184

          lewtot184 Well-Known Member

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          i couldn't slide the cap and side seals in together. what I had was very tight. the method I used did work well with some tightness on install. I think the blue side seals may be better than the original stuff when properly installed, but I've never had a rear main leak using OEM parts. I don't understand how people have such problems with the seals. I really think they are getting some weeping from up top on the engine or pan gaskets and it's traveling back by the seal. the real test is if the flywheel/converter are wet up by the seal.
           
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          • 65-440

            65-440 Well-Known Member

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            What I did : a small bead inside the channels where the seals go. I put the seals in the retainer roughly 1/4" sticking out of the top. A slim coat on the outside ood the seals. It is slippery ! But with the seals sticking out of the top of the retainer by the time the reainer is flush with the block the side seals will have slid into position. I've done this with the hollow seals and the solid blue seals.
             
          • sam65

            sam65 Well-Known Member

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            that is used if crank is already in the block,the small end goes between block and seal so the seals backside isn't cut rotating the seal in the block.
             
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            • velrob

              velrob Well-Known Member

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              hm so with that thing i can change a seal without taking out the crank?

              thats great good to know that, thx
               
            • khryslerkid

              khryslerkid FBBO Gold Member FBBO Gold Member

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              Last edited: Dec 1, 2017
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