Genuine Audi 100 Belt Tensioner

Audi 100 Belt Tensioner Parts and Q&A

• Tensioner Pulley
  078-109-243-K
  Q: What precautions should be taken regarding the Belt Tensioner before starting work and how should the timing belt be handled on Audi 100?

  A:

  Before starting work, disconnect the battery. To gain access to the components, remove the auxiliary drivebelts. Set the engine to TDC on No 1 cylinder, then remove the upper section of the timing belt outer cover. Slacken the retaining nut at the hub of the tensioner pulley and allow the assembly to rotate anti-clockwise, relieving the tension on the timing belt. Remove the nut and recover the washer, then slide the tensioner off its mounting stud. Wipe the tensioner clean without using solvents that may contaminate the bearings. Spin the tensioner pulley by hand; stiff movement or excessive freeplay indicates severe wear, and the tensioner should be renewed. Slide the tensioner onto the mounting stud and engage the forked end of the backplate with the timing belt pillar if necessary. Refit the tensioner washer and retaining nut without fully tightening it at this stage, then refit and tension the timing belt. Restore the fuelling system by reconnecting the fuel cut-off solenoid wiring, refit the timing belt covers, then refit the auxiliary drivebelts and reconnect the battery. Set the engine to TDC on No 1 cylinder, remove the camshaft cover, and slacken the retaining nut at the hub of the tensioner pulley to relieve the tension on the timing belt. Carefully slide the timing belt off the camshaft sprocket, holding the camshaft sprocket stationary while slackening its retaining bolt. If access to the correct special tool is not possible, a simple home-made tool may be fabricated. Using the home-made tool, brace the camshaft sprocket and slacken the retaining bolt half a turn, then release the sprocket from the camshaft taper mounting by tapping it with a soft metal drift. Remove the bolt and the camshaft sprocket, then examine the camshaft oil seal for signs of leaking and wipe the mating surfaces clean. Locate the sprocket on the camshaft, insert the retaining bolt hand-tight, check that the engine is still set to TDC on No 1 cylinder, then refit and tension the timing belt. Refit the timing belt upper cover and the camshaft cover, then refit the auxiliary drivebelts and reconnect the battery. Remove the timing belt and the upper and lower outer covers, ensuring the timing belt is marked for direction of rotation if it is to be reused. Hold the crankshaft sprocket stationary while slackening its retaining bolt; if access to the locking tool is not available, lock the crankshaft in position by removing the starter motor and using a screwdriver to hold it while slackening the bolt. Withdraw the bolt, recover the washer, and lift off the sprocket, then examine the crankshaft oil seal for signs of leaking and wipe the mating surfaces clean. Offer up the sprocket to the crankshaft, engaging the lug with the recess in the end of the crankshaft, insert the retaining bolt, and tighten it to the specified stage 1 torque while holding the crankshaft stationary. Angle-tighten the bolt by the specified angle, then check that the engine is still set to TDC on No 1 cylinder, refit and tension the timing belt, and reassemble the timing belt outer covers and auxiliary drivebelts before reconnecting the battery. Remove the timing belt and the upper and lower outer covers, ensuring the timing belt is marked for direction of rotation if it is to be reused. Hold the intermediate shaft sprocket stationary while slackening its retaining bolt; if access to the special tool is not possible, a home-made tool may be fabricated or a metal dowel rod or socket wrench may be used. Slacken and remove the retaining bolt, then slide the sprocket from the end of the intermediate shaft and recover the Woodruff key. Examine the intermediate shaft oil seal for signs of leaking and wipe the mating surfaces clean. Fit the Woodruff key into the keyway with the plain surface facing upwards, engage the slot in the sprocket with the Woodruff key, and insert and tighten the sprocket retaining bolt to the specified torque while holding the sprocket using the method employed during removal. Check that the engine is still set to TDC on No 1 cylinder, then refit and tension the timing belt, reassemble the timing belt outer covers, and refit the auxiliary drivebelts before reconnecting the battery.