MAZ water pump repair

Repair of the water pump YaMZ-2Z6NE, NE2, BE, BE2 of the MAZ car

A characteristic malfunction of the water pump is water leakage through the impeller seal as a result of wear of the textolite ring

A gland seal malfunction is indicated by water leakage from the drain hole on the water pump housing, which can be eliminated by turning the textolite ring over with the reverse side (not worn) to the end of the sleeve pressed into the housing, or by replacing the ring with the simultaneous replacement of the rubber cuff.

Blocking the drain hole to eliminate stuffing box leakage is not allowed, as water seeping from the pump enters the bearings and disables them.

To repair the stuffing box seal, you need:

• - remove the water pump from the engine; unscrew the nuts securing the housing cover, remove the cover and gasket;
• - holding the roller from turning by the pulley, unscrew the cap nut and remove the impeller from the pump roller with a puller, remove the retaining ring of the impeller stuffing box and remove all parts of the stuffing box from it.

The suitability of stuffing box parts is determined by visual inspection. The textolite ring should not have chips, tear cracks on the working surface.

Minor scratches and risks are eliminated by grinding the rings. The stuffing box collar must be elastic, without tears, fit snugly against the shaft and the textolite ring.

Assemble the impeller seal in the following order:

- insert the stuffing box spring into the impeller housing, then the rubber cuff assembly with the inner and outer races, the textolite and retaining rings of the stuffing box.

After installing the retaining ring, the textolite should move freely along the grooves of the impeller when pressed by hand and return to its original position under the action of the spring.

The part of the pump shaft, on which the rubber cuff sits, must be lubricated with soap before installing the impeller, and the end of the sleeve in contact with the textolite ring must be a thin layer of graphite lubricant.

This eliminates the possibility of tearing the working surface of the cuff and improves the quality of grinding in the working surfaces of the textolite ring and the end of the sleeve.

After the impeller is in place, the cap nut for fastening the impeller must be tightened to failure and locked with a washer.

When the pump is completely disassembled to replace the bearings and the roller, the impeller is removed from the pump roller, as indicated above;

• - unscrew the pulley fastening nut and remove the pulley from the pump shaft using a puller;
• - unscrew the fastening screws and remove the bearing cover;
• - remove the roller assembly with bearings and bushings from the pump housing.

In the presence of cracks of any size and location, the case is not repaired, but replaced. During repairs, felt seals are replaced with new ones, after soaking them with grease.

Assemble the pump in reverse order. The housing cavity between the ball bearings must be filled with Litol-24 or TsIATIM-201 grease.

After assembly, grease must be added through the grease fitting until grease appears from the control hole. After assembly, the pump roller must rotate freely, without jamming.

When installing the pump on the engine, it is recommended to replace the gasket between the pump flange with the distribution gear cover.

The mating planes of the pump flange and the roof of the distribution gears must first be cleaned of the remnants of the old gasket, and the new one must be lubricated on both sides with a sealing non-drying paste.

DISASSEMBLY AND ASSEMBLY OF THE WATER PUMP

• 1. After loosening the water pump drive belt tensioner, remove the belt from the water pump pulley.
• 2. Drain coolant from engine and radiator.
• 3. Remove the inlet pipe from the water pump.
• 4. After unscrewing the mount, remove the water pump from the engine, carefully without damaging the gasket.
• 5. Loosen the nuts 14 (Fig. 2) of the branch pipe 8.

• 6. Lightly tapping on the protruding parts of the pipe 8 in the direction of the arrows B, remove the indicated pipe from the pump housing 1.
• 7. Secure impeller 2 (or pulley 10) against rotation with shaft 5.
• 8. Unscrew the plug 7 from the threaded hole of the impeller 2.

• 9. Screw the nut 17 of the puller into the threaded hole (M22 x 1.5) of the impeller 2 (Fig. 3, 4) and, screwing in the bolt 18, press the impeller 2 off the shaft 5.
• 10. Bend the "mustache" D case 19 mechanical seal (Fig. 3) and remove the collar 22 with the spring and frames as an assembly.
• 11. Using a puller, press pulley 10.
• 12. Remove the retaining ring 9 from the groove of pump housing 1.
• 13. Press shaft 5 with water deflector 6 and bearings 13 out of housing 1.
• 14. If the brass body 23 of the mechanical seal is not damaged, it can not be removed from the body 1 and the disassembly of the pump can be considered complete.

HOW TO ASSEMBLE THE WATER PUMP

• 1. Rinse all pump parts and dry with compressed air.
• 2. Press on the shaft 5 (fig. 2) the bearings 13 and the water deflector 6. In this case, it is necessary:
• — pre-lubricate shaft 5 with diesel oil;
• —install bearings 13 so that the sealing washers are on the outside;
• —apply the pressing force to the inner ring of the bearing.
• 3. Fill the entire cavity between the bearings with Litol-24 grease (60...70 g).
• 4. Press the shaft assembly with bearings and water deflector into housing 1 until it stops. This requires:
• — pre-lubricate the housing bore 1 for bearings with clean engine oil;
• —apply the pressing force to the outer ring of the bearing.
• 5. Install the circlip 9 into the groove of the housing 1.
• 6. Press pulley 10 onto shaft 5 until it stops. This requires:
• — pre-lubricate the shaft with clean engine oil;
• —provide a fixed stop for the opposite end of the shaft.

• 7. Install the parts of the mechanical seal into the brass body 19 (Fig. 4);
• - rubber cuff 22 assembled with a spring and spring cages;
• - reinforced cuff 20 and sealing sleeve 21.
• 8. Install the rubber cuff 23 and the sealing sleeve 21 into the impeller 2. In this case, it is necessary:
• —preliminarily put on the cuff 23 on the sealing sleeve 21;
• - apply a thin layer of lubricant into the bore of the impeller 2 and on the outer surface of the rubber cuff 23;
• - take the cuff assembly with the sleeve with both hands and, applying force to the end of the sealing sleeve, insert these parts into the impeller bore until it stops, avoiding distortions.
• 9. Press the impeller 2 complete with the cuff and sealing sleeve onto the shaft 5 (Fig. 2). This requires:
• — pre-lubricate shaft 5 with clean engine oil;
• —provide a fixed stop for the opposite end of the shaft;
• - install the impeller on the shaft in a size of 10-0.15 mm (Fig. 2) between the end of the shaft and the end of the impeller hub, for this it is necessary to install a disk with a diameter of no more than 13 mm and a height of 10-0 on the shaft end when pressing 15
• 10. Secure impeller 2 (or pulley 10) against rotation.
• 11. Screw plug 7 into the threaded hole of the impeller 2 until it stops;
• 12. Install sleeve 4 and rubber ring 12 into housing 1.
• 13. Install the rubber ring 11 into the groove of the pipe 3, preventing it from twisting.
• 14. Press the branch pipe 3 into the body bore 1 until it stops. This requires:
• - pre-lubricate the bore in the body 1 ring 11 with a thin layer of grease Litol-24;
• - the studs on the body 1 must freely enter the mounting holes of the nozzle 8.
• 15. Fasten the nozzle with 3 nuts 14 with spring washers 15.
• 16. Check the quality of assembly by rotating shaft 5 by pulley 10. The rotation of the shaft must be free, without jamming.