Rebuilding the Inline 6 cylinder Water Pump
October, 1996

There appear to be three types of water pumps:

• No magnetic clutch; or
• With magnetic clutch with straight water neck, casting no. 52291; or
• Magnetic clutch with a curved water neck, casting no. 53351,

not a lot of difference between the magnetic clutch types. Here's what you do:

Remove the pump from the car (not very difficult, just be careful), start disassembly. Best to refer to parts manual. In this instance we will refer to Mistral Parts Manual, Table 5:

1. Remove magnetic fan assembly from water pump by undoing 4 bolts. Loosen the nut that holds the fan, be careful as this bolt is counter-threaded. To loosen turn clockwise. Remove the fan. You can now remove the bearings from the housing. Careful not to damage the grease seals
   
2. Remove castellated nut (fig. 18), remove the top part of the magnetic clutch. Remove the 3 screws holding the magnet (fig. 14). If you are lucky these nuts will not be corroded. If they are, you will drill them out carefully. Turn the pump around and with an impact driver, remove the screws that hold the back cover.
   I have found spraying a lot of WD40 does help. 99% of the time I have found these screws to be butchered by someone else or corroded beyond repair. If this is the case, drill them out carefully. Should the cover be damaged it will need to be tig welded and machined, drilled and counter sunk. Should the water pump body bolts stick, they will need to be drilled and inserts fitted.
   
3. Once you have the back cover off, tap the shaft out gently, insuring you note where the spacers go. Once you have everything disassembled, clean all parts thoroughly.
   
4. Re-assembly starts with the nylos grease seal (fig.10) and new bearing (fig. 11), which is best pressed in with an hydraulic press, but can be tapped in gently with a plastic hammer.
   
5. Turn the pump over and install your seal, very carefully, with the copper side facing the bearing. The actual seal is made of carbon and can break very easily.
   
6. Insert the impeller through the seal and bearing ... best pressed.
   
7. Place spacer (fig.13) on top of bearing (fig.11)
   
8. Attach magnet using new screws (fig.16). Attach magnet (fig.14)Tap down pulley very carefully, lining up the woodruff key (fig.5) with the grove. Fit tab washer (fig.17) and castellated nut (fig.18). Tighten with special tool or old screwdriver very carefully. DO NOT OVERTIGHTEN as it can break the carbon seal.
   
9. The seal has a spring inside and this should be compressed about half-way and the nut locked into place. Re-install the fan assembly over this. The cover plate on the back of the pump should have a layer of pink silicone to seal it properly.

The time required to rebuild a water pump is approximately 4 hours ... if all goes well ... believe me that is rarely!

Should you experience any problems, do not hesitate to contact me. If it's on this matter or something else, I'll do my best to help.

Mario Lombardi