series 3 windscreen mount bolts

[73series88]

ok guys and gals,
what are people doing to seal the mount bolt that goes through the wind screen frame. when i got the truck someone siliconed them and it all was a mess. cleaned it up and put some fat rubber washers in there. put it still leaks like crazy. this is going to be the demise of my bulkhead if i cant get this sealed up. leaks down into the dash and comes out on the floor in gaint puddles.
thanks\
aaron