I'm about to replace calipers on a friend's '64 122 sedan. In the event that I'm unable to bleed the rears (the bleeder nipples on the calipers are MIA) I may have to source new rear cylinders. On the chance that they're Wagner, it would help me to know the Wagner number when going to the local parts store. I'm presuming they're the 7/8"diameter, but I haven't been under the rear to measure mounting hole space to more clearly identify them. thanks