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  •  » Preferred Center Section Sealing Method

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    1/29/2026 5:26 PM  #1

    BroPaul
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    From: Fresno CA
    Registered: 10/04/2023
    Posts: 142

    Preferred Center Section Sealing Method

    I've built a lovely and new (to me) center section for my 9" rear.



    The one in there is RPM's and it's RTV sealed,  no gasket. Expecting a fight to remove it. IIRC getting my Detroit Locker center section off (also RTV sealed) was a serious mofo. Super stuck. Not 100% certain, but I believe I recall removing all the nuts and raising the rear of the car with a floor jack under the pinion area of the center section. I thought it would come loose, but it most certainly didn't without a herculean fight. The cleanup with wire wheel preceded several of those wires ending up deeply imbedded in my back. No bueno.

    Then, I saw this from MS in the GeeZee pan thread. 

    MS wrote:

    I do not follow the argument that RTV is hard to clean up. I have a very sharp 1” wood chisel that takes it right off. Also, I bought s spray can of FORD SILICONE GASKET REMOVER for $1 at a swap meet. You spray it on the stuff and it almost just wipes off with a rag. To remove a glued-on pan, I use the same wood chisel as a wedge. I drive it between block and pan and walk away. Come back later and the pan has magically separated from the block.

    SILICONE GASKET REMOVER!!! Doh. I think I have some of that already. DOH!!!

    So from the wisdom above can I infer that a wood chisel + patience strategy would also work on separating my pumpkin from the housing???

    65 Fastback, 422W, Roller C4, 14" front discs, 9" rear,  front coilovers, SorT A-arms
     

    1/29/2026 8:31 PM  #2

    Mochaman
    Senior 24-7 FYI Addict

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    From: Royse City, Texas
    Registered: 4/02/2013
    Posts: 1,519

    Re: Preferred Center Section Sealing Method

     

    1/29/2026 9:36 PM  #3

    MS
    Forum Originator

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    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,702

    Re: Preferred Center Section Sealing Method

    Any kind of tapered chisel will work, but a differential is a little more challenging than an oil pan, intake or valve cover.
    Just drive a small flat screwdriver or chisel into the joint once the nuts are removed. Once you get it started it will then separate easily.

    While using only RTV seems to be a good idea, as far as sealing the third member, I always use a gasket plus paper thin RTV each side of it. My reasoning is that, without a gasket, the axles will enter the differential about 0.020” rearward from where they belong, causing the wheels to toe in ever so slightly and putting the wheel bearings in a bind. I am not sure this causes an issue, but I do not want to find out, so I do it like the factory built it.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    1/30/2026 8:04 AM  #4

    TKOPerformance
    Hyper FYIFORD ADDICT

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    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,908

    Re: Preferred Center Section Sealing Method

    Use a Lube Locker gasket and never clean up RTV or buy another gasket again.  Anything else is insanity.  

    https://www.lubelocker.com/products/ford-9-axles-llr-c900

    I run these on both the front and rear axles in both my F250s, and have many miles on them with zero issues.  I changed the gear lube after a gear break in in my '06 truck (10.5" rear) and cleaned up the gasket and surfaces with some brake cleaner, threw it back together, and all was well.  There was zero damage to the gasket.  I literally just spent about a minute cleaning off any oil.  Well, well worth it.  Honestly, a tube of RTV is $10-$13 anymore.  Twice that for a gasket that eliminates the mess and lasts forever?  No brainer.  

     

    1/30/2026 8:17 AM  #5

    BobE
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    From: White Plains, NY
    Registered: 4/04/2013
    Posts: 2,932

    Re: Preferred Center Section Sealing Method

    I typically use a ‘razor’ type scraper (single blade w/replaceable razors) to remove any difficult RTV from any surface.  Sometimes a wire bush will work. 
    To break the seal, I have also used a paint scraper, both the flexible (thinner) and stiff (thicker) type.
    I agree with MS’s carrier removal method, and will add that the studs are a tight fit to the housing and must be removed, and installed, ‘square’ to the housing, which not easy to do.  I also use a gasket with a thin coat of RTV to both sides. 
     

    65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
     

    1/30/2026 9:32 AM  #6

    Raymond_B
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    From: Fort Worth, TX
    Registered: 4/01/2013
    Posts: 1,270

    Re: Preferred Center Section Sealing Method

    TKOPerformance wrote:

    Use a Lube Locker gasket and never clean up RTV or buy another gasket again.  Anything else is insanity.  

    https://www.lubelocker.com/products/ford-9-axles-llr-c900

    I run these on both the front and rear axles in both my F250s, and have many miles on them with zero issues.  I changed the gear lube after a gear break in in my '06 truck (10.5" rear) and cleaned up the gasket and surfaces with some brake cleaner, threw it back together, and all was well.  There was zero damage to the gasket.  I literally just spent about a minute cleaning off any oil.  Well, well worth it.  Honestly, a tube of RTV is $10-$13 anymore.  Twice that for a gasket that eliminates the mess and lasts forever?  No brainer.  

    100% agree on Lube Locker, used this on rear end housings and trans pans. So nice.
     

     

    1/30/2026 10:13 AM  #7

    Michael H.
    I FYI 24-7

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    From: Laurel, MS
    Registered: 4/01/2013
    Posts: 925

    Re: Preferred Center Section Sealing Method

    I had never heard of Lube Locker gaskets or Silicone Gasket remover... both sound very helpful.
    Once again y'all have taught me something new.  Thank you!

     

    1/31/2026 7:41 AM  #8

    Nos681
    Senior 24-7 FYI Addict

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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
    Posts: 3,523

    Re: Preferred Center Section Sealing Method

    I have used two methods on the 8”.

    1) Small bead of RTV on housing side with circles around each stud and a gasket

    2) Lube Locker gasket with clean dry surfaces

    Used copper washers for both under the nuts.

    I will have to say with all of the “tolerance issues” Ford had with body panels and suspension, this is one area that was actually precise…from an electrician’s point of view, not a machinist.

    Referring to the drop out carriers and studs.


     

     

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