Disassembly:
Some engines require a modification in the tensioning roller and/or the guide rollers due to possible failures. Refer to the concessionaire.
Remove the air filter box.
Lift and support the vehicle part
Remove the right front wheel
The wheel pass and the upper engine cover does.
Mark with chalk the direction of rotation of the auxiliary drag strap.
Weave the strap removing the tensioning roller. Use a ring key. You can use a 14mm key and grab for the end of the tensioner.
Insert a 4mm pin into the tensioner anchor hole.
Remove the auxiliary drag strap.
Remove the upper cover from the distribution (2).
Support the engine with a cat in the crankcase.
Corsa/Astra/Vectra-C/Signum/Zafira/Meriva Disassemble:
Auxiliary drag belt tensioner and motor side taco.
Install the crankshaft locking pin in the clutch envelope (3).
Disassemble:
Crankshaft pulley screw (4).
The crankshaft pulley (5).
The crankshaft locking pin (6).
The lower distribution cover (3).
The camshaft position sensor (if it carries).
Provisionally mount the crankshaft pulley screw (4).
Turn the crankshaft to the right to PMS of cylinder No. 1 and check the alignment of crankshaft adjustment marks (7).
The adjustment marks of camshafts must align with the upper plane of the butt (

.
Block the piñones of camshafts (9).
Loosen the tensor roller screw (10).
Turn the tensor to the right until the index of the latter stops on the left.
Use an Allen key (11).
Type 1 (12)
Type 2 (17)
Tighten the tensioning roller screw without blocking it (10).
Remove the distribution strap.
Note: If you have to reassemble the used strap, mark with chalk its direction of rotation.