Early type flat-tipped bleed screw - Girling cylinders produced in the 50s & early 60s were originally fitted with a flat-tipped bleed screw which contacted with a steel ball. The ball made a seal when pushed against the conical seating at the bottom of the cylinder's port. Some purists may wish to retain the original parts, although the bleed screw & ball can be replaced by the later tapered type bleed screw. BEWARE, it is easy to overlook the ball at the bottom of the port & to screw in a new tapered bleed screw.The tapered screw will produce a considerable force on the ball & this has on occasions resulted in splitting the brake cylinder body. Good for Alfa Stop but not good for you!