A dispensing head assembly comprising a needle (26) having a sealing surface (38) at one end; a housing (30) in which said needle (26) is mounted for reciprocating movement; an elastomer guide (32) in said housing (30) slidably receiving said needle (26), there being approximately a zero tolerance between said guide (32) and said needle (26); and a seat (40) against which said needle sealing surface (38) abuts. <IMAGE>
