Greasing truck shackles, in particular rear shackle pins that take weight and dust constantly. When no grease will flow, jack up the chassis to relieve the weight of the shackle pin, at the same time as greasing, tap the spring or shackle pin with a hammer. If that fails apply heat (oxy acetylene) directly on the blocked area, not too long or too hot, but enough heat to melt the dust and grease which is set hard, at the same time pump in grease. This method is not suitable on all grease points, especially ball joints that sit on nylon seats. What is nearly impossible to grease are the HQ style Holden steering crossover drag link ball joints. Any ideas on this as you cannot now buy a new drag link to overcome this fault?