To fit a new fan belt slacken slightly the two bolts on which the dynamo pivots and release the bolt securing it to the slotted link and the nut securing the slotted link to the engine. Move the dynamo to the engine as far as possible. Remove the old belt, then slide the new belt over the fan and onto the fan pulley; ease the belt onto the crankshaft pulley and dynamo pulley.
Adjustment is made by raising the dynamo upwards away from the engine. A gentle hand pull only must be exerted on the dynamo, or the tension will be excessive and undue strain will be thrown onto the dynamo bearings. Tighten up the bolts with the dynamo in this position. The belt should be sufficiently tight to prevent slip, yet it should be possible to move the belt laterally 1in (2.5cm) in the centre of its longest run.
On cars fitted with alternators the fan belt is renewed and adjusted in a similar manner.
Please click on the picture below to see a video of how to do this job