Hey dude I've done the axles seals a few times now, I dunno if that's the same as the "inner" seals you mention or if there is another seal I don't know about but they need to be tapped in perfectly square. You need a socket with overall diameter about the same size as the axle seal so that when you tap the socket it taps the seal around the entire circumference. You can also use some PVC pipe, measure the size of the housing then get a bit of pipe as big as can fit. Keep the pipe exactly parallel with axle housing and gently tap the seal in. Bit of grease on the seal helps.
If the seal is even slightly not square or tapped slightly unevenly it will jam.