C-10 front caliper rebuilding question

[vics stuff]

Hey Guys ! I have been messing with these trucks for over 4 decades. Always have information to pass on to others . This time I am needing some help.
As a purest , I am rebuilding my front brake calipers on my 72 C-10 truck. My question is , I am having issues pressing in the new Raybestos outer rubber dust seals with the metal ring. I keep bending them when pressed in , i am using a machined piece of pipe that is the same diameter as the metal ring. I have tried to press the seal in with and without the piston captured in the rubber seal. I am at witts end . Any help is always appreciated.
Vic