Replacing and adjusting the tension of the ZMZ-402 engine generator drive belt
Remove fan drive belt
Loosen the two bolts securing the generator to the bracket
Loosen the alternator adjusting bar bolt.
Loosen the adjusting bolt and rotate the alternator towards the engine block.
Remove the alternator belt.
Installing the alternator drive belt
Put belt 1 on water pump pulley 2, then on crankshaft pulley 3 and alternator pulley 4.
After installing the belt, adjust its tension.
Adjusting the alternator drive belt tension
At the correct tension, the belt should deflect 8-10 mm when a force of 40 N (4 kgf) is applied midway between the water pump and generator pulleys.
Loosen the two bolts securing the generator to the bracket and the bolt securing the generator adjusting bar.
Loosen adjusting bolt 1 and, turning the alternator away from the engine block, tighten the belt
Tighten bolt and check belt tension as above.
If the belt tension is normal, then tighten the bolts securing the generator and the adjusting bar.
The belt is installed in accordance with the engine number according to the catalog 4025.1308020 with a length of 1030 or 1050. Usually they take an old belt and orient themselves along its length.