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using silicone instead of gaskets

Discussion in 'Ford Trucks' started by dany, Feb 25, 2002.

  1. dany

    dany Member
    Messages: 89

    Ive got a leak around my rearend cover and was wondering if I could use silicone instead of a gasket. I know a machanic that avoids gaskets when ever possible. He uses 514 locktight gasket maker. Ive alwaysed used it on the bottomends of the sleds i rebuild but will i get a better seal on my rearend?
  2. CT18fireman

    CT18fireman Banned
    Messages: 2,133

    I would not worry about it to much for a rearend. Why not use the gasket though?

    I would tend to stay away from it (unless called for) on anything that is internal in an engine. Also keep in mind that you only need a thin coat. I see many people put way too much on. If it squeezes out on the outside then it is on the inside as well.
  3. E-man

    E-man Junior Member
    from west.PA
    Messages: 5

    They make a product called gasket shellack. use it with your gasket, It goes on like a liquid and does not squeeze out like a like RTV would.
  4. plowjockey

    plowjockey PlowSite.com Sponsor
    Messages: 622

    There is also a product called "high tack" that remains pliable when used to seal a gasket into place. It comes in a small can and goes on with an included brush. I've had great luck with this product in any and all applications in the past.

  5. 75

    75 PlowSite.com Addict
    Messages: 1,382

    Ideally, if there is a gasket used for a particular application I try to put a gasket back in.

    In the real world that isn't always practical, and I have had good luck using silicone (also referred to as RTV for Room Temperature Vulcanizing) where necessary. One example is the king pin caps on my K-35 front axle. Make sure the surfaces are clean and free of oil/grease etc.

    Keep in mind that RTV was never intended to fill large gaps or make up for poorly fitting parts.
  6. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    Go ahead,and use silicone,it will work fine,the only thing i do is clean the area several times with parts cleaner,the more grease free you get it,the better the seal.I use Silicone whenever possible too,it is much better than gaskets,when applied correctly it will not leak.You will need a chisel/hammer to pry that diff cover off after you put silicone on it!Thats the biggest drawback to silicone,it bonds like glue when applied to a greae-free surface.

    ADLAWNCUTTERS Senior Member
    Messages: 212

    john is right on the money.clean the cover and housing, has to be very,very, clean.it will work fine and won't leak.
  8. I use brake cleaner to clean the surfaces. Have used RTV this way (no gaskets) for years w/out problems. A mechanic who puts rears in large trucks started me doing it. He swears by the stuff. He also uses starting fluid as a cleaner, says it does just as good a job, dries fast and is .88 cents a can.
  9. plowjockey

    plowjockey PlowSite.com Sponsor
    Messages: 622

    Just remember that starting fluid is mostly ether and EXTREMELY flammable.

  10. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    Most newer trucks don't have gaskets anymore, they rely solely on silicone. Cleanliness is extremely important, brake cleaner works well, and follow the directions on your sealer. I use Permatex, you squeeze it on, let it tack over and assemble.
  11. Dockboy

    Dockboy Guest
    Messages: 0


    As has been said before, they don't use gasket's anymore. I pulled my rear cover and installed a Mag-Hytec. The stock one was on with silicone. The Mag-Hytec has an o-ring in the flange so you don't have to use anything with it;)

  12. thelawnguy

    thelawnguy PlowSite.com Addict
    Messages: 1,011

    If its a Dana you cant even get a gasket. Use blue RTV for the rear, gray for the front.
  13. dany

    dany Member
    Messages: 89

    What is the difference between the blue and gray RTV? What is different from front to rear?
  14. thelawnguy

    thelawnguy PlowSite.com Addict
    Messages: 1,011

    Different temps. It was explained to me that the front needs the higher temp stuff due to engine heat etc. I have used the black RTV for exhaust manifold use on my leaf blower with no problems so far.

    If memory serves me, from coolest use to highest temp use its blue, red, gray, black but I could be mistaken...
  15. dany

    dany Member
    Messages: 89

    Thanks guys!

    Wont be able to fix the leak for a while though. Had alittle accident and my right arm will be tied up for about 3 weeks. Really bad cut.
    I'll fix the leak as soon as I can. Trucks a standard to. Haven't quite worked that one out yet??