Hi i have the same problem i have stripped my kango down to a part that looks like a bar fixed on to a rotating wheel .On the end of the bar is a 2 inch by about 1.5 inch plunger which should have 1 or 2 rubber bands in 2 circular grooves this plunger fits into a metal sleeve to create a compression which forces everything forward to create the hammer action. The problem i can see is the rubber bands need replaced as the compression power is escaping out of the sleeve because it is not sealed tight enough to push the sleeve the extra half inch to hit the the bar that hits the chisel.
Richard from CORBY, February 2010
