GASKETS - prep and sealing vs. not?

Farmall Super A, AV, 100, 130, & 140 1939 - 1973

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Dale Finch
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GASKETS - prep and sealing vs. not?

Postby Dale Finch » Mon Mar 07, 2011 11:39 am

I have reached the point in my '48 SA restoration where I am cleaning gasket and seal surfaces in preparation for reassembly. Units include, but are not limited to, carb, valve cover, rear engine seals (paper and felt), oil pan, final drive oil pans, pto and belt pulley, final drive, transmission cover, etc. Materials are cork, paper, felt, seals, o-rings, etc.

In the past I have been told "no sealant", RTV (red or black?), Permatex (type?), and so forth. What I am looking for is a consensus from you "experts" on just what is the best.

1. How do I prep the metal surface after making sure it is clean and free of old gasket material and rust and gunk?
2. Should I use any kind of sealant on:
paper gaskets?
cork gaskets?
felt seals? (rear engine seal)
exhaust manifold gaskets?
shims? (metal-to-metal and they have been cleaned with emory-cloth)
lip seals? (don't most new ones come with a "sealing film" on outside?)
3. If I use a sealant, do I let it tack up or bolt the parts together right away.
4. How tight against cork, paper, etc, do I tighten down the bolts?
5. And any other pointers you can think of!

Thanks in advance...again!

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Re: GASKETS - prep and sealing vs. not?

Postby Eugene » Mon Mar 07, 2011 1:20 pm

I scrape first then use a very fine emery paper/cloth to clean up surfaces for gasket installation.

Some of the gaskets require no sealant such as the manifold to block. Your choice on the remainder of the gaskets. Head gasket - I use CopperKote.

Torque. Follow the recommendations in the Service Manual. Pan cork gasket - just snug up evenly - don't over torque. If the pan gasket leaks you can snug up the leaking area bolts a bit.

All of the above - just my personal opinion.
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Re: GASKETS - prep and sealing vs. not?

Postby Georgia Boy » Mon Mar 07, 2011 2:12 pm

I never use anything on the gaskets other than a very thin layer of 3M weather strip adhesive to hold the gaskets in place. I don't use anything on the head gasket (EDIT: I now recommend using copper kote on the head gaskets for these old tractors), i clean the sealing surfaces of the head and block with an angle grinder with a medium grit scotch brite pad attached (purchased at a Lowes tool department). When installing o rings I do put a thin layer of oil on them before installation. The only time I use a sealer is when I am working on boat motors and I use the 3M 847 as added protection from water getting into the lower unit and if I remove a part and want to reuse the gasket, then I will put a thin layer of permatex on the gasket before I put it back on. Just the way I do things.
Last edited by Georgia Boy on Mon Mar 14, 2011 9:59 am, edited 1 time in total.

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Re: GASKETS - prep and sealing vs. not?

Postby Gator809 » Mon Mar 07, 2011 3:00 pm

If I can, I use a mill file to clean and smooth out gasket surfaces. I then clean with brake cleaner and a rag.

Paper Gaskets I ether use a thin layer of Permatex Ultra Gray RTV, or Permatex #2 aircraft grade gasket maker.

Cork I use 3M 8001 weather strip adhesive AKA Gorilla Snot. USE IT VERY SPARINGLY. If you have to remove the gasket later, be prepaired to have to scrape and chisel the gasket off.

I've never put sealent on shims, they crush and make they're own seal.

Seal I just drive them home, they are oversized so when you drive them in, they seal against the bore.

Never have delt with a felt seal.

Exhaust, clean an smooth with the file and brake cleaner. If it's the fiber steel layered ones, I use no sealent, just clean and torque them, and a retorque after the first few heat cycles.

O rings I use the fluid they are going to be sealing to lubricate them.

I follow the directions on whatever sealer/gasket maker I use, they spend a lot more time and money figuring out how to make it work best than I can spend.

Just follow the torque recomendations, making sure to follow any patterns for torquing something down, if none is provided, try and pull the titem down evenly to prevent possibly stress cracking the part.


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Re: GASKETS - prep and sealing vs. not?

Postby Bigdog » Mon Mar 07, 2011 3:36 pm

For what it's worth:
Head gaskets - copperkote
paper gaskets - nothing - exception would be a dab of grease etc. to help hold it in place during assembly.
Cork gaskets such as oil pan or valve cover - sealant such as RTV or Permatex on the side that the pan or valve cover contacts.
Exhaust manifold - nothing
Shims - nothing
Felt seals - these are typically dust seals and I leave them dry
Rubber seals - light coating of oil or grease - whichever is handy just to reduce drag or prevent hanging up during shaft insertion.
O - rings - lubricate liberally with hy-tran or whatever lube they are functioning in.
I think everything else has been addressed.

All gasket surfaces should be as clean and smooth as possible prior to application of the gasket.
If a seal or o-ring has to go on over the length of a shaft I try to tape over any sharp edges that might nick the o-ring or seal surface.
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