Remove the engine oil pan (see Oil pan replacement).
Using a 13 mm spanner, unscrew the two bolts securing the oil pump...
...and remove it from the engine. There is a gasket between the pump and the cylinder block.
Using a 10 mm spanner, unscrew the three mounting bolts and remove the pipe from the pump.
We remove the pressure reducing valve with the spring from the branch pipe...
...and a thrust washer.
We remove the cover from the pump.
We take the leading... out of the housing.
...and the driven gear.
If the housing, cover and gears are heavily worn, replace the pump.
The original is posted on Internet resource VazBook
We assemble and install the pump in the reverse order, lubricating its parts with engine oil.