The water pump is centrifugal type. Located and fixed on the chain cover
The roller bearing 7 is separated from the coolant by a self-tightening gland 4 of a non-separable design, inside which a cuff and a sealing washer are located
The liquid seeping through the stuffing box does not enter the bearing, but flows out through the control hole 6, which must be cleaned periodically.
The bearing is kept from moving by retainer 3, which is screwed up to the stop and centered.
The bearing is filled with grease during assembly; no additional grease is required during operation.
Hub 1 and impeller 5 are pressed onto the bearing shaft.
The water pump and generator are driven by a V-ribbed belt. During operation, it is necessary to periodically check its tension.
The deflection arrow "A" (Fig. ) between the pulley 5 of the generator and the pulley 7 of the water pump, when pressed with a force of 8 daN (8 kgf), should be 15 mm.
The belt tension is adjusted by the tension roller 2, equipped with a fastening bolt 3 and a displacement bolt 6.
To adjust the belt tension you need:
- - loosen the bolt 3 fastening the tension roller;
- - move the roller 2 with the bolt 6 to the position that provides the required belt tension;
- - tighten the tension roller mounting bolt;
- —Check belt deflection.
Fan* plastic, six-bladed, mounted on the hub of the water pump drive pulley through a threaded bushing with a left-hand thread M24x1.
On buses with 6 passenger seats, instead of a fan with a belt drive, an electric fan with automatic switching on is installed.
Removing the water pump
Drain the engine cooling system.
Remove the radiator.
Remove the alternator drive belt.
For engine 4062
Unscrew the three bolts 1, holding the pump shaft from turning with a screwdriver 2, and remove the deflector 3 and the water pump pulley 4.
Unscrew fitting 3 and disconnect tube 4 from the pump.
Remove bolt 1 for fastening the pump, loosen clamps 2.
Disconnect the outlet hose 1 of the radiator from the pump by loosening the clamp 2.
Remove the mounting bolts 1 and remove the water pump 2 and the water pump gasket.
For ZMZ-402 engine
Remove four screws 1 and remove fan 2 and fan pulley 3.
Disconnect hose 2 for draining fluid from the heater from the water pump by loosening clamp 1.
Disconnect the hose 3 from the pump by loosening the clamp 4.
Unscrew the fastening nuts 1 and remove the pump 2 with the pump gasket.
Water pump disassembly
Pumps mounted on motors mod. 4062 and 402 are similar in design.
This shows the disassembly of the motor pump mod. 4062.
For motor pump mod. 402, you must first unscrew the two bolts and remove the pump cover with gasket.
Next, the procedure for disassembling both pumps is the same.
Remove pump impeller 1 using a puller.
The impeller is molded from plastic, but has a metal hub, in which a thread for a puller is cut.
Compress the hub 1 of the pump pulley with a puller.
Unscrew retainer 2 of the bearing and press the bearing with the pump shaft towards the pulley.
Press out the oil seal of pump 1.
Rinse and clean the pump parts from deposits.
Inspection of water pump parts
The bearing on the pump shaft must rotate freely without binding, otherwise replace the bearing with shaft assembly.
If a large play is felt in the bearing, traces of lubricant leakage from under the protective rings are noticeable or the balls roll when the bearing rotates, it must be replaced as an assembly with the roller.
Inspect the impeller. If it has cracks, chips, etc., replace it.
Inspect the gland. If it has tears, cracks, the rubber has lost its elasticity, the compression spring is broken, replace the oil seal.
Water pump assembly
Pressing on the pulley hub and water pump impeller
А = (117.5±0.2) mm (motors mod. 402 and 4021);
H = 0 / 0.2 mm (motors mod. 402 and 4021);
C = 0.9 / 1.3 mm (motor mod. 4062)
The pump is assembled in the reverse order of disassembly. When assembling the pump, inspect the gaskets, if they have tears or the gaskets are heavily compressed, they must be replaced.
When pressing the impeller and hub, the emphasis should be on the pump shaft.
When assembling the pump, keep the dimensions shown in the figure.
After screwing in the bearing retainer, you need to punch out the edges of the hole so that part of the metal enters the slot of the retainer to prevent self-loosening.
Installation is carried out in the reverse order of removal.