Question about front main seal.

Discussion in 'Street/strip 400/430/455' started by green71stage1, Jun 10, 2021.

  1. green71stage1

    green71stage1 Well-Known Member

    I have a pretty bad front main seal leak and when my mechanic fulled everything apart he noticed the seal was not sitting in the housing very snugly. The new one seemed tighter when he just placed in it. We noticed what appears to be a ring that the seal sits in. (see pics) Is that replaceable? If not, should a little JB weld be ok to use? Also is my Harmonic balancer original? My mechanic who has never worked on a Buick before never seen one with the grooves in it? Thanks for the help
     

    Attached Files:

  2. green71stage1

    green71stage1 Well-Known Member

    Pic of Balancer
     

    Attached Files:

  3. Max Damage

    Max Damage I'm Working on it!

    The new seal should be interference fit with the case. This means it should be TIGHT, too tight to just place in there, usually it need to be pressed or driven home.
     
  4. green71stage1

    green71stage1 Well-Known Member

    Copy that Max! Thats what my mechanic said. How do I fix the problem of it not being tight? Thanks
     
  5. john.schaefer77

    john.schaefer77 Well-Known Member

    The grooves are there for the rope seal to ride on. You can put a sleeve on it because the grooves will cause a leak. The sleeve I have used is 99200. Napa carrys it but may have to order. Rock auto also has it.
     
  6. green71stage1

    green71stage1 Well-Known Member

    He used a sealer and it had to be forced in so I'm good to go thanks
     
  7. Max Damage

    Max Damage I'm Working on it!

    John is talking about the grooves in the balancer in case that isn't clear, and the sleeve goes over that area.

    I am not sure how to make that timing case work other than maybe getting another seal that fits it? I'm sure someone here knows a way to fix this...

    Some of the replacement timing case covers have the seal on the front (can be replaced without pulling off the case).
     
    john.schaefer77 likes this.
  8. srb

    srb Well-Known Member

    Your balancer looks identical to mine. I'd say it's correct.
     
  9. green71stage1

    green71stage1 Well-Known Member

    Thanks Stefan
     
  10. john.schaefer77

    john.schaefer77 Well-Known Member

    Yes, as Max said I was referring to the balancer knurling (grooves). The rubber seal that can replace the rope seal goes on from the rear on original GM timing covers. If your rubber seal is riding on the knurling on the balancer, it probably will not seal.

    450446 was the seal I used on my covers.
     
  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  12. Matt Knutson

    Matt Knutson Well-Known Member

    I would clean up all the machined surfaces where the seal will live on the balancer and the front cover and get the paint off of the rubber on the balancer (both sides) to help keep the rubber from developing more cracks in the surface of the rubber. Definitely use the 450446 National seal.
     
    Last edited: Jun 10, 2021
  13. green71stage1

    green71stage1 Well-Known Member

    My mechanic is not a fan of sleeves. Where can I get a replacement balancer? Thanks
     
  14. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  15. green71stage1

    green71stage1 Well-Known Member

    Larry they are out of stock
     
  16. Matt Knutson

    Matt Knutson Well-Known Member

  17. green71stage1

    green71stage1 Well-Known Member

    Man I'm having zero luck finding a new balancer. Summit, the parts place, old buick parts, TA (they are making their own not available yet) and the ones that did have one also have knurled surfaces. I guess the only choice to to use the original without sleeve or talk my mechanic into using one.
     
  18. Max Damage

    Max Damage I'm Working on it!

    I think those grooves are not the mating surface for the seal. As long as the smooth part of the balancer is smooth, I think it should seal?

    On the other hand the dampening part of the balancer is rubber, which does eventually die.

    Matt's references to rebuilders would replace the rubber bit. I think those knurls are just an attempt to sling the oil away from the seal? Maybe more knowledgeable folks can comment.
     
  19. Matt Knutson

    Matt Knutson Well-Known Member

    Why do you think it needs a sleeve?
     
  20. srb

    srb Well-Known Member

    I don't have a sleeve either and have a neoprene seal. I found out during my rebuild, but it doesn't leak. I did find it somewhat strange but ok. I'm actually not fully sure if the mating surface is the knurled part.
     

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