take the clamps of so theres nothing holding them in,then scoot some lube around them & im sure a 15/16 mm spanner fits the top of the injector,& in a clockwise direction twist it a wee bitto get it to move,then if the whole injector starts to move use a pair of small pipe pliers to wiggle it & pull upwards,id be weary of using a sliding hammer incase it breaks the top of the injector