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Can't get my diff to stop leaking. Help please

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by '73 K5, Jun 13, 2000.

  1. '73 K5

    '73 K5 1/2 ton status

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    Can\'t get my diff to stop leaking. Help please

    I just put on my T/A performance rear diff cover and I already have about 3 different leaks on it. I used a gasket and a bunch of blue RTV high temp sealant. How long are you supposed to let the RTV "set-up" before you bolt the cover on the truck? And how long should I let it sit empty before I put any gear lube in it.
    This diff cover has a drain plug in it, which means I shouldn't ever need to take it off again, so I want to seal it up REAL good. Help

    '73 K5
    Chevy good...Ford bad
     
  2. Jason73K5

    Jason73K5 1/2 ton status

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    Re: Can\'t get my diff to stop leaking. Help please

    You shouldn't really need to use high-temp sealant there. the standard blue silicope should work. I usually just apply a very thin coat of sealant to the surfaces and immediately put it together. The most important parts of assembly are torquing the fasteners properly (amount of torque and order) and making sure all parts are clean. One of the most common causes of leaks is overtorqued fasteners, which warp the mating surfaces. Silicone needs at least 24 hours to properly cure, but usually waiting an hour or so will be enough to fill it up.
     
  3. MICHIGAN BLAZER

    MICHIGAN BLAZER 1/2 ton status

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    Re: Can\'t get my diff to stop leaking. Help please

    agree w/ jason....you could have over torqued them, thus oozing all of your silicone out and possibly bending something a little bit...enough to make it leak.....where you sure to take a gasket scraper, or something similiar to the surfaces really good?

    <font color=red>MICHIGAN BLAZER
    <font color=green>89 Fullsize Blazer
    87 Cherokee
    65 IH Scout
     
  4. Todd78/87

    Todd78/87 1/2 ton status

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    Re: Can\'t get my diff to stop leaking. Help please

    I don't even use gaskets. Just Black RTV. CLEAN both surfaces very well. Use a good size bead, let it sit for 5-10 mins,,, put it on. Alternate bolts as you tighten slowly.

    Todd 78/87[​IMG]
    [​IMG]
    Alaska Bound
     
  5. '73 K5

    '73 K5 1/2 ton status

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    Re: Can\'t get my diff to stop leaking. Help please

    The torque is definitely not the problem. T/A Performance supplied a sheet with the needed torque values and I used a Craftsman torque wrench on everything.
    I'm thinking I just didn't wait long enough or something.

    '73 K5
    Chevy good...Ford bad
     
  6. smack

    smack 1/2 ton status

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    Re: Can\'t get my diff to stop leaking. Help please

    My diff has two sheared off bolts on it -- one on the bottom -- and it never leaks. What I do is make sure both surfaces are clean, then apply a thin coat of hi-tack to the cover. Wait for it to get tacky than place the gasket on. I also apply hi-tack to the diff itself. Never a problem.
     
  7. Burt4x4

    Burt4x4 3/4 ton status

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    Re: Can\'t get my diff to stop leaking. Help please

    I too never use a gasket!
    I run a bead of BLACK RTV on both cover and diff let sit for 20 min so it gets set up then do the crisscross tightning deal and have never had a leak.
    my pappy once told me that the use of RTV is color coded
    Blue=water
    Black=oil
    Red=Hightemp/exhaust
    Clear=rubber seals like windows and stuff
    I have allways used this as a guideline and it has never let me down!

    Rock ON![​IMG] 72 K5 [​IMG] Led Zeppelin
    http://burt4x4.coloradok5.com
     
  8. AZK5

    AZK5 1/2 ton status

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    Re: Can\'t get my diff to stop leaking. Help please

    I never use RTV, yuck what a mess that makes and takes a week of scraping to get it off. Just use the gasket. I take my cover off several times using the same gasket over again. If you don't use RTV then take a large flat file and take all the burrs off of the housing and cover gasket surfaces. You have to take the cover off every time you change the fluid to get all the metal particles out of the housing and off the magnet. Just pouring the dirty fluid out through a drain hole isn't good enough. I flush my diff with brake cleaner. Let it dry and then bolt it back together. Using just the gasket makes field repairs a snap.
    CB
     

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