Does anyone know what the thread size is for the rear opening of a 1970 442 manual disc brake master cylinder? The front is 1/4" I believe and is available at any auto parts store. The rear however is something that I can't find. Need to bench bleed the cylinder and need a barbed fitting or an adapter that will work.


Thanks

Rick

 

GM used non-standard flare nut fitting threads to prevent incorrect installations on the assembly line. The available thread sizes are:

3/8-24
7/16-24
1/2-20
9/16-18

 

Thanks Joe