[AussieinNC]

I use a slightly modified section of 4" pvc pipe ( from plumbing supply section of Lowes or Home Depot) about four inches long as a driver to set the seal....you have to use a die grinder to open the end of the PVC a little so the seal will seat properly.

I then place a piece of 2x6 across the other end of the pvc tube to act as a hammer surface.

If I am building an engine on a stand I press the seal into the carrier using the same pipe and block....

They can be a beast to install sometimes...I've also machined a very small angle cut on the bore of the holder...no more than 1/16" to allow the seal to start without binding on the housing.

Hope this helps...