1. Remove the oil pump from the car (see «Removal and installation of the oil pump»).
2. Drain the oil from the pump.
3. Turn out five screws of fastening of a cover of the oil pump...
4....and remove it.
5. Remove the pressure relief valve retainer.
Warning! The pressure reducing valve spring is installed with an interference fit. Remove the latch very carefully to avoid injury.
6. Remove the stopper...
7....spring...
8.... and the pressure reducing valve plunger.
9. Measure the radial clearance between the gears and the pump housing. It should be 0.110–0.249 mm.
10. Measure the axial clearance of the gears. It should be equal to 0.020–0.086 mm. If the measured clearances are not within specifications, replace the housing or pump assembly.
11. Flush the pump housing and dismantled parts from dirt and deposits. Remove dense varnish deposits from the internal cavities of the pump, after softening them with a solvent.
Note. Lacquer oil deposits are well removed with commercially available engine flushes (so called «five minutes»).
12. Inspect the pump housing and cover. If there are cracks, scratches, casting defects, damaged threaded holes, replace the housing (because it is unrepairable) or pump assembly.
13. Check the pressure reducing valve plunger for scratches or binding. Small dents and burrs can be removed with a fine grit sanding stone.
14. Check the pressure reducing valve spring for permanent deformation and bending. Replace damaged spring.
15. Check gears for metal spalling, scuffing and tooth wear. Replace damaged gears or gears with noticeable increased one-sided tooth wear.
16. Assemble the pump in the reverse order of disassembly.