In order to remove the timing belt and the crankshaft sprocket the oil pan must be removed, and the oil pick-up tube unbolted from the bottom of the pump housing. Subsequently, it is necessary to remove the spring, the plug and plunger of the safety valve and the tensioner for the timing belt. Remove the oil pump-to-block bolts, paying attention to different lengths and locations before carefully separating the front case from the engine. Remove the cover from the back of the casing and take out inner and outer oil pump gears and after that take out the crankshaft oil seal from the front casing. Clean every component completely, removing any remnants of old gasket material, thoroughly inspect visually for any indications of wear, cracks, or damage; replace damaged components as necessary. Install the oil pump outer and inner gears, measure clearances, and compare these with the specified values. Measure the free length of the pressure relief spring and check whether it measures to specification or not. If it does not meet specification, necessary components must be replaced. Fill the pump cavity with petroleum jelly, fix cover fastening bolts to specified torque and ensure the gears are engaged to each other with matching markings. Then, fit a new crankshaft front oil seal and the pressure relief valve bits, tightening the plug. With a new gasket, position the pump in place on the engine and install the bolts in the correct position according to length, and tighten to torque. To conclude this task, reinstall the parts in reverse order of removal. Lastly, add oil, start the engine and check the oil pressure and leaks.