Paper Vs Cork Gasket

Had a hydraulic gasket blow Saturday on my tractor. It was the paper seal where the filter cartridge cover bolts to the housing.

I have a lot of cork gasket material that I could make one from but am concerned that it won't hold up under the pressure of the hydraulic system.

Would the cork hold up or should I buy some paper type material?

I wouildn"t use cork anywhere that there is going to be more than a few psi of pressure.

Valve cover only. If you have two machined surfaces RTV will work ok.

My experience with "pure" cork material has mostly been with valve cover gaskets on '60s-vintage cars. The cork would eventually become saturated all the way through with oil -- and that's not a high-pressure application! I don't recall any bad leaks, but those gaskets eventually got very black and brittle; little pieces broke off very easily. So, I probably wouldn’t use that stuff on a hydraulic system if I could avoid it.

There is also what I would call a cork-rubber mix; you can see the pieces of cork interspersed with pieces of black rubber or vinyl or whatever it is. I used this type of gasket with good results (again, not on hydraulics), but due to the aforementioned experience with cork I coated both sides as well as the edges with a VERY light skin coat of silicone (to keep the cork from absorbing/transporting any oil). But again, that was no high-pressure application, and I don't know how the gaskets would have fared without the silicone.

Silicone itself is good stuff and can do the job, but I would try to use as little as I could get away with. Once you crank down on those bolts, it’s surprising how much of that stuff squeezes out of the joint – inside and outside. It’s tough, rubbery stuff, and even the smallest piece that gets loose inside can raise Cain with valves and orifices.

I think I would probably try one of Permatex’s non-silicone products first (I don’t remember which one, maybe it’s Permatex #2). If a piece gets loose it may not cause quite as many problems as a piece of silicone could.

You may want to bounce the Permatex idea off someone at the auto parts store or a local hydraulic shop. Whichever way you decide to go, please let us know what you do and how well it works.

Mark W. in MI