C-clamp to the calipers

[Michael Williams]

Hi guys
When I was working on my front calipers awhile back I was trying to get the piston back into the caliper. A guy at an auto shop said to use a C-clamp to push it back in. Phil Payne said that was fine for the fronts but not for the rear calipers. What's the reason for that? The car in question is an 89-100. Sorry Phil, I can't find your email to send this to you directly.
Thanks 
Mike Williams