Well the bolts on my y pipe to cat flange on one side have gone... missing. They must have been loose front the installer and progressively gotten more loose until they just fell out! Does anyone know the size of these bolt/nuts and how I can get two more and a gasket??

 

I did some research and came up with a temporary solution until I get to the shop. If anyone happens to have this happen to them this is what you could use. If you're just trying to get to the shop forget the gasket. Pick up some M10x1.25 OR M10x1.50 35MM or greater bolt and nut in same thread size (1.25 or 1.50) and bolt up your parts. You'll create a good enough seal as to be able to make it to the shop and get a proper fix, if you don't have the ability to do it otherwise.