For this procedure the Volvo
Camshaft locking tool 999 5452 is needed to adjust the position of the camshafts and the crankshaft during the removal of the
Timing Belt sprockets; details of how to make home-made equivalents are given. Start by taking off the cover panel from the engine and timing belt, then the entire air cleaner assembly and inlet ducts to get to the camshafts. Disconnect the brake servo vacuum hose from the throttle housing, unscrew the bolt to release the fuel pipe support bracket and prise the sealing cap from the left-hand end of the cylinder head to expose the inlet camshaft. Disconnect the wiring from the camshaft position sensor, remove the screws to release the wiring harness guide, remove the camshaft position sensor housing screws. Observe the position of the slots in the back of the camshafts and make sure they are parallel to the join between the upper and lower cylinder head sections before locking them in place. Check that the crankshaft sprocket timing marks are lined up, then put the locking tool in place, turning the camshafts a bit if needed. Mark the sprockets for identification, remove the relevant camshaft sprocket to get access to the failed seal, and on models with variable valve timing, unscrew the centre cap to access the sprocket bolt. Carefully remove the seal, clean and lubricate the seal seat and slide the new oil seal over the shaft. Refit the camshaft sprockets with timing marks lined up, only putting two bolts in to start with, and check the sprockets are free to rotate within the parameters of their elongated holes. For models with automatic timing belt tensioners, release the tensioner and check its operation while for manually-adjusted tensioners, perform necessary operations. Tighten all bolts to specified torque, remove locking tool, turn crankshaft clockwise through two complete revolutions and check timing marks. Continue with the refitting procedure for the timing belt without reconnecting the battery at this point. Refit camshaft position sensor trigger wheel and housing, reconnect sensor wiring, push new inlet camshaft cover cap into position, refit wiring harness guide, reconnect brake servo vacuum hose, refit air cleaner assembly and ducts, replace cover panel and reconnect battery negative lead.