Curtin Flush Valve Issues

I have just replaced one of these in an old American Standard toilet circa 1937. Did a similar toilet several years ago. This one had no instructions, don't think the earlier one did either. In both cases, I had immediate leaks past the leather gasket. The surface of the gasket looks very rough and is impregnated with a greasy substance. In both cases I had to replace the leather gasket with one I fabricated from a piece of soft sheet rubber. The older toilet has been working fine for probably 10 years with this fix- hopefully the new one will too. Questions: Is my experience typical, or am I supposed to be prepping the gaskets in some way? I should mention that I checked the brass flange surface very carefully and found it to be perfect in both cases. The dealer said he had had no complaints, though I suspect he has sold very few of these. (Has Curtin gone out of business? Not surprising since most of these toilets are long gone I'd guess.) For you green folks, I do know these toilets are water wasters, but this is a historically important house and I hesitate to change the original fixtures. (The house has a Putnam steam boiler as well.) Help much appreciated- and thanks for your help in advance! Frank

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.