Remove from the outside,, just carefully press a small sharp-bladed screwdriver into the face of the seal to pierce a small hole, then with a piece of strong wire with a hook bent on the end, pull it straight out. If you have a tool something like a dentist pick you could use that instead.... then press the new one in and carefully tap home with a small socket on the end of an extension bar (1/4” drive will be small enough) put some silicone grease on the new seal to help avoid damage when fitting it.