To remove the camshaft pulley you will need some means of holding it still while undoing the bolt. A universal tool is available, such as in this link:
http://www.ebay.co.uk/itm/LASER-TOOLS-2869-CAMSHAFT-HOLDING-TOOL-/310452240070?pt=LH_DefaultDomain_3&hash=item4848653ec6 or, I always use a large screwdriver held through one of the pulley spokes and resting on a step in the cylinder head. If using this method, you may need one person to hold the screwdriver solid, while another loosens the bolt. Loosen the bolt until it's just finger tight while the old timing belt is still fitted.
Next, turn the crankshaft pulley nut clockwise until the camshaft timing mark is aligned with the pointer inside the plastic cover. At this point, the mark in the crankshaft sprocket should be at the 9 o'clock position in relation to the vertical center-line line of the engine. Then loosen the 13mm (spanner size) split lock nut that holds the timing belt automatic tensioner and remove the timing belt. You can then fully remove the camshaft pulley bolt and pulley.
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