Hi, I am replacing a failed/corroded master cylinder and brake booster. I need the square gasket between the booster and cast aluminum bracket, and can't find it. Is it OK to cut it out of gasket paper and go for it?
Ha: the booster I bought was perfect, only it was not painted at all. That's what I've been doing this weekend: painting it instead of installing it. Also the master cylinder.

 

Any gasket would be fine but to be honest you really wouldn't really see any ill effects if you left it out. You could also use some RTV sealer. There are plenty of cars that don't use any gasket at all
Regards
Jay

 

When I was working on cars as a poor man, you could buy gasket material to make your own, but I did this a very long time ago. But it seems the stuff is still around !

Gasket Material | AutoZone.com