As far as I know the oldest pumper running the streets (July, 2009) is reserve piece S-105, one of two 1998 Seagrave wagons delivered in 1998. These two wagons were equipped with extrication equipment (no longer). Recently disposed E-60 (S-104) went to Engine Co. 31 when new and S-105 was assigned to E-27.
Summer 2008 photo, Trinidad, DC
Kevin Byrne