1. Remove the oil pump from the vehicle (see "Removal and installation the oil pump").
Note: If the sealing gasket remains on the pump body and is not damaged, it can be left on the body. In this case, when reinstalling the pump, lubricate the gasket with a thin layer of sealant.
2. Drain the oil from the pump.
3. Remove from the housing bore with any pointed tool (for example, with a screwdriver) front crankshaft oil seal.
Fig. 5.14. Oil pump parts: 1 - oil pressure drop sensor; 2 - Oil pressure drop sensor gasket; 3 - oil pump mounting bolt; 4 - front crankshaft oil seal; 5 - pump body; 6 - safety valve; 7 - driven gear; 8 - leading gear; 9 - housing cover; 10 - screw for fastening the cover; 11 - housing gasket; 12 - pressure reducing valve plug; 13 - plug gasket; 14 - pressure reducing valve spring; 15 - plunger; 16 - oil receiver; 17 - oil receiver mounting bolts; 18 - guide bushing
4. Unscrew the sensor B of the emergency oil pressure drop signal lamp from the oil pump housing adapter, and the safety valve B and plug A of the pressure reducing valve from the pump housing. Remove spring 14 (Fig. 5.14) and plunger 15 of the pressure reducing valve from the housing cavity.
Warning: The pressure reducing valve spring is installed with tension. To avoid injury, remove the plug carefully.
Please note: there is a sealing gasket under the pressure reducing valve plug, do not lose it.
5. Remove the five screws securing the pump cover...
6 - and remove the cover.
7. Remove the leading... from the housing cavity.
8 - and the driven gear of the pump.
9. Wash the pump body and dismantled parts from dirt and deposits. Remove dense varnish deposits from the internal cavities of the pump, having first softened them with a solvent.
Helpful advice: Varnish oil deposits are easily removed with commercially available engine flush products (so-called "five-minute" products).
10. Inspect the pump body and cover. If there are cracks, scratches, casting defects, damaged threaded holes, replace the body (because it is not repairable) or the pump assembly.
11. Check the relief valve plunger for scratches and signs of seizure. Small dents and burrs can be removed with a fine-grained sanding stone.
12. Check the pressure reducing valve spring for residual deformation and bending. Replace the damaged spring.
13. Check the gears for metal chipping, scoring and tooth wear. Replace damaged gears or gears with noticeable increased one-sided tooth wear.
14. Check the axial clearance between the ends of the gears and the surface of the pump cover. This can be done in two ways.
15. In the first method, measure the thickness of the leading...
16. ...and the driven gear...
17. ...and also the depth of the bore in the housing for the gears. Calculate the axial clearance as the difference between the arithmetic mean of the bore depth and the thickness of the gears.
18. In the second method, install the driven gear into the housing, put a metal ruler (or caliper) end on the body and measure the gap between the body and the ruler with a feeler gauge.
19. Measure the axial clearance of the drive gear in the same way.
20. The maximum permissible clearances measured by both methods should be 0:045-0.100 mm for the driven gear and 0.035-0.085 mm for the driving gear.
21. Assemble the pump in the reverse order of disassembly. Before pressing it into the pump cover, lubricate the front crankshaft oil seal with engine oil. Apply Loctite 573 or similar sealant to the threads of the pressure relief valve plug and tighten the plug to 30 N·m (3.0 kgf·m). If you are installing a new gasket 11 (see fig. 5.14), glue it to the body with grease.
Warning: Use only the original factory gasket. Installing a gasket of a different thickness will cause the pump to malfunction. To avoid engine damage during the first start after installing the oil pump, fill the pump cavities with consistent mineral grease before installing the gears in its housing to ensure oil suction from the oil sump.
If the oil pressure does not immediately rise to the required level when the engine is first started with a replaced oil pump, stop the engine immediately, remove the oil pan and check the tightness of the pump connection to the oil receiver. If necessary, disassemble the pump again and refill its cavities with consistent grease. If there is no required pressure in the lubrication system, even a short-term operation of the engine leads to its emergency damage.