Briefly describe the disassembly and assembly steps of automobile water pump

First, remove the engine from the car.

In general, it is only necessary to remove the engine from the vehicle when the engine is overhauled for assembly replacement and repair, or when the engine must be replaced due to an accident. It is also very common for Santana car to run more than 1.5 thousand km without overhauling its engine because of reasonable use and proper maintenance.

When disassembling the engine assembly from the automobile, the general principle is to disconnect the engine assembly and its accessories from the circuits, gas circuits and oil circuits of other systems on the automobile, and often disassemble them at the same time as the transmission assembly.

The disassembly direction is upward from the position of the automobile hood, and the special lifting tool for lifting is VAG 1202, as shown in Figure 2- 1. It should be pointed out that the specific disassembly sequence can be different, but relatively independent, that is, the outermost accessories that have little interference with other parts are always disassembled first. Here is a recommended disassembly method.

1) Remove the connecting wire between ECU, sensor and actuator of EFI engine.

2) Remove the air filter.

3) Remove the grounding wire from the battery.

4) Turn the heater switch to the "heating" position.

5) Open the radiator cover.

6) The coolant pump has three inlets, starting from the liquid outlet of the radiator, which is called the large circulation inlet; A second inlet of the coolant pump from the hot air outlet; Coolant pump inlet during small cycle. We take it out of the large circulating inlet of the coolant pump, release the antifreeze coolant and collect it in a container for future use.

7) Pull off the coolant hose from the coolant outlet of the cylinder head (all the way to the radiator) and keep the clamp.

8) Remove the thermal switch (tee) and the connecting wire on the electric fan.

9) Loosen and remove the fixing brackets at the left and right corners of the top of the radiator, take the radiator out as a whole together with the cooling fan and wind deflector, and keep it properly.

10) Remove the wiring of the alternator to completely disconnect it.

1 1) Remove the oil inlet pipe, oil outlet pipe and oil return pipe of carburetor (only applicable to Santana 2000 car with carburetor gasoline engine).

12) Remove the vacuum pipe and oil return pipe from the fuel pressure regulator.

13) Remove the fuel filter of the fuel inlet pipe before the nozzle.

14) Remove the central high-voltage line, ignition high-voltage line and other related lines and plugs from the distributor cover (the third-generation model has no distributor).

15) Remove the throttle (accelerator) control cable and related accessories.

16) For carburetor gasoline engine, the vacuum connection pipeline should be disassembled: pull off the vacuum tube from the vacuum tank; Unplug the vacuum tube from the vacuum propulsion device of the distributor; Pull off the vacuum tube of the brake vacuum booster from the intake pipe.

17) Remove the wiring of intake manifold glow plug; Remove the thermal switch wiring; Remove the wiring of the power terminal.

18) Remove the electric wire on the sensor of coolant thermometer and unplug the connecting wire from the oil pressure switch.

19) Loosen the fastening bolt on the bracket and remove the clutch control wire rope below.

20) Loosen the fixing bolt on the rubber bumper of the left leg of the engine and the fixing bolt on the rubber bumper of the right leg of the engine.

2 1) Remove the fixing bolts of the engine front support frame; Remove the connecting bolt of the exhaust pipe chuck; Remove the lead of the starting motor.

22) Remove the fixing bolts of the starting motor.

23) Loosen the connecting bolt between the engine and the transmission.

24) Put the hanger chuck at the rear end of the engine and tighten the connecting bolts.

25) Remove the toothed belt guard (or remove it after lifting the whole machine).

26) As shown in Figure 2-2, put it into the hanger. At the pulley end of the spindle, insert the pin into the third hole in position 3. At the flywheel end, insert the pin into the No.8 hole (the 1-4 hole marked on the hanger faces the pulley, and the position of the template iron hole is counted from the hook end). The bolt and hook are both secured by spring cotter pins.

27) Lift the engine slightly to separate it from the engine bracket, and then retighten the supporting bolts of the fixture of VW785/ 1B suspension seat.

28) Pull out the connecting bolt between the engine and the transmission to separate the engine from the transmission. Tilt the engine block and gradually lift the engine. At this time, the action should be slow, the operation should be very careful, and the contact between the engine and the outside world should be paid attention to at any time to avoid damaging related structural parts during lifting.

29) Fix the engine on the assembly frame (rotatable frame) with VW540 bracket.

The engine installation sequence is basically opposite to the disassembly sequence, but there may be several installation sequences with different local sequences.

The following points should also be noted before installation.

1) Check the wear of the clutch release bearing and replace it with a new release bearing if necessary.

2) Apply a thin layer of molybdenum disulfide grease to the release bearing and transmission spline, but do not apply it to the guide sleeve of the release bearing.

3) Replace the rubber bumper of the engine support foot and the self-locking nut of the bumper fixing bolt.

4) After the engine is hoisted into the bracket, don't tighten the bolts immediately, and make the engine sit in the correct position by shaking it.

5) Adjust the free stroke of the clutch pedal to keep it at a distance of about 15 mm ... [top]

Second, the disintegration of the engine.

Only when the engine needs to be overhauled, or it must be disassembled for inspection in case of an accident, can the engine be disassembled.

(1) Disassembly of engine peripheral accessories

The air filter, radiator and cooling fan have been removed in advance, and will be further decomposed according to the maintenance needs in the future. In fact, there is no obvious order for the disassembly of other peripheral accessories, but it should be noted that it involves following the principle of small to large.

1) Remove the throttle position sensor.

2) Remove the air pressure sensor and air temperature sensor.

3) Remove the oil pressure regulator.

4) Remove the fuel filter.

5) Remove the fuel injector.

6) Dismantle the knock sensor (it can be done after removing other peripheral parts).

7) Remove the oxygen sensor and coolant sensor.

8) Remove the ignition coil.

9) Remove the connecting pipe that has not been removed from the water pump.

10) Remove the water pump.

1 1) Remove the distributor (2VQS model has no distributor).

12) Remove the starting motor.

13) Remove the generator.

14) Dismantle the gasoline pump (for carburetor gasoline engines) (for EFI gasoline engines, the gasoline pump is in the fuel tank).

15) Remove the oil filter base and oil filter assembly.

16) Remove the intake pipe and exhaust pipe.

17) Loosen the power steering pump drive belt and remove the power steering pump and its bracket.

(2) Remove engine front cover parts, such as V-belt and toothed drive belt.

1) Loosen the fastening bolt of the generator support arm and remove the V-belt of the engine water pump (sometimes it has been loosened before lifting the engine).

2) Remove the V-belt drive wheel of the spindle, and the tightening torque of the fastening bolt is 20N m. ..

3) Remove the guard plate on the toothed belt, and the tightening torque of the fastening bolt is10n m (sometimes removed before lifting the engine).

4) Remove the toothed belt lower cover, and the tightening torque of its fastening bolts is10n m (sometimes removed before the engine is hoisted).

5) Loosen the fixing nut of the toothed belt tensioner with a tightening torque of 45 N m. Turn the eccentric shaft of the tensioner to loosen the toothed belt and remove it.

6) Remove the toothed pulley of the main shaft and the toothed pulley of the intermediate shaft. The specification of the former fastening bolt is M 12× 1.5, and the tightening torque is 80N·m；; ; The tightening torque of the latter fastening bolt is 80 N m. ..

7) Remove the rear guard plate of the toothed belt.

Figure 2-3 shows the disassembly of front-end parts, such as the toothed belt of the engine.

8) The automobile power steering pump and transmission belt can also be disassembled at this time.

(III) Engine disintegration

1) Remove the oil pan assembly and replace the oil pan gasket.

2) Remove the oil pump and the primary oil filter assembly. Then clean and test. If the performance degradation value exceeds the specified value, the test should be further decomposed or replaced with new parts or components.

3) Remove the bonnet and replace the bonnet gasket.

4) Remove the cylinder head assembly. Remove the camshaft bearing cover, and the tightening torque of the fastening bolt is 20N m. ..

Remove the camshaft. Remove the valve hydraulic tappet, valve spring retainer ring, valve spring and valve (in engines after 1997, the hydraulic tappet is fluorinated). When removing the cylinder head, loosen the fastening bolts of the cylinder head in a certain order (please refer to the tightening instructions of the cylinder head bolts).

5) Turn over the cylinder block assembly and loosen the crankshaft bearing cover and connecting rod bearing cover. The tightening torque of their fastening bolts is 65 N m. Remove the crankshaft flywheel group, the clutch assembly, the flywheel and the crankshaft. The tightening torque of the flywheel fastening bolt is 75 N m.. When installing, replace the new bolts and apply D6 locking glue to the threads.

6) Remove the intermediate shaft (the intermediate shaft is cancelled for the 2VQS engine).

7) Turn the cylinder block in the installation direction, take out the piston connecting rod group, and then remove them.

(4) Tightening torque of important engine bolts (N m)

1) Fastening bolt between engine and transmission M 12——55

2) Fastening bolts from valve cover to cylinder head-10

3) Spark plug to cylinder head -20

4) Fastening bolts of engine front bracket on cylinder block -25

5) Connecting bolt between engine and transmission cover plate-10

6) Fastening bolt of front exhaust pipe of transmission bracket -25

7) Exhaust pipe connecting bolt at exhaust pipe elbow -30

8) Fastening bolt between engine bracket and engine foot -35

9) Fastening bolt of starting motor -20

10) Fastening bolt of radiator lower bracket-10

1 1) Oil drain plug of oil pan -30

12) Fastening bolt from oil filter flange to cylinder block -20

13) Oil pressure switch to cylinder head -25

14) Fastening bolt from water pump to cylinder block -20

15) Thermal switch of cooling fan -25

16) Fastening bolt from alternator bracket to engine -45

17) cylinder bracket to alternator -20

18) Tightening torque of cylinder bolts:

1 time is 40N·m；; ;

The second time is 60 n m;

The third time is 75 N m;

For the fourth time, continuously tighten 1/4 turns (90) with a wrench.

19) Two specifications have been used for connecting rod bolts: M9× 1 and M8× 1. The tightening torque of the former is 45 N m; The tightening torque of the latter is 30 N m..

20) Fastening bolt between flywheel and crankshaft flange -75

2 1) Fastening bolt of crankshaft main bearing cover -65