I was fortunate that, while the local Case dealer couldn't find a replacement water pump (part number K902192), repair kits were still available (part number K903213). These contain the integral bearing/shaft assembly, along with it's set screw and retaining strap, a new gland seal, and both gaskets required for the pump housing and mounting plate as shown in the picture to the left. One was promptly ordered and received a few days later, when I noticed that while the parts manual calls for a bearing/shaft assembly part number 11651, the kit ships with part number K262796, which I imagine is an equivalent.

Unfortunately, upon receiving the kit, several other oddities were noted. The first and foremost being that the impeller shaft looked nothing at all like the one that was in there. Not only was it too short, but the impeller end was much to small in diameter. I first thought it was due to the wrong bearing/shaft assembly being shipped in the repair kit. But then I also noticed that part number stamped on the impeller I had was nothing even close to the one the parts manual states I should have. The cross section diagram of the water pump seemed to confirm that it was the wrong impeller, as it was completely different than the one shown, yet the bearing/shaft assembly looked to be accurate. To end the debate one way or the other, the local Case dealer got the mechanical drawing for the correct impeller, (part number K902131), which was not the one I had. Another order was placed, this time for a new impeller, and several more days wasted.

The new impeller seemed to be just right, so the first thing to do was to clean up everything in preperation for reassembly. First, all the cast parts (housing, mounting plate, thermostat housing, etc..) were sand blasted to remove all the old paint and other gunk. Then, since it will be some time before I can get to painting things, a couple coats of red oxide primer were applied to prevent surface rust. A brake cylinder hone was used to clean up the bearing bore, and a metal cutting disk mounted in the drill press polished up the seal mating surface quite nicely. Once good and clean, the bearing/shaft were pressed into the hosing bore with a little marvel mystery oil, followed by the impeller and finally the belt pulley. The temperature sending unit was reinstalled along with a cleaned up grease nipple. All that was left was to install it on the tractor. I went to the local auto parts store and found a 180 degree thermostat that would fit, along with a new radiator hose that was suitable for both the upper and lower portions after a bit of snipping. You can see the original and new parts in the picture to the right. The electric cord on the original lower radiator hose attaches to a heater element that was previously installed in the tractor. You plug it into house current when things get cold out to keep the water in the block from freezing. I don't think it was an original part, and since it rarely freezes where I live, I don't think I'll reinstall it right away.

Following my previous sucesses, I reinstalled the water pump on the tractor, filled the radiator with water, and promptly noticed water streaming out from the bottom weep hole on the pump. After about two dozen tries assembling and disassembling the pump trying to get it to hold water, I finally realized that the seal was not reaching it's mounting surface on the water pump housing, even when the impeller was pressed in as far as it would go. I at first attributed it to wear on the mating surface, but since the seal is plastic and the surface is metal, I could hardly see it getting worn down that far. The only thing I can imagine is that either it was one of those undocumented design changes suitable for the old shaft/seal, or that someone machined it down to accept the old shaft/seal and it's unusual configuration from the pumps design. Anyway, the problem was solved by placing a flat washer under the seal (which raised it almost 1/8th of an inch) and pressing the impeller on as far as it would go without the vanes hitting the pump housing. After reinstalling on the tractor, it seems to be working perfectly, however, it does give me a good reason to make getting the water temperature guage working a top priority now.

Rebuild Procedure

The shop manual lightly touches on rebuilding the water pump, so here is the procedure with a bit more detail, based on what I had to do to my own water pump. The procedure starts with removal of the pump itself so it can be worked on.

1. Mark with a scribe or marker the relationship between the fan blade positions and the pump pulley. This will be used for reassembaly to ensure the relationship remains the same, as these were balanced at the factory.
2. Remove the 4 bolts holding the fan blades on to the pump pulley and then remove the fan blades.
3. Loosen the dynamo adjusting bolt to remove tension on the fan belt, then remove the fan belt.
4. Remove the top and bottom radiator hoses.
5. Remove the 4 bolts holding the water pump to the engine block. One of the left bolts also serves as a mounting point for the dynamo bracket, which will fall loose upon removal. Use a piece of 2x4 wood block or similar to prop up the dynamo so excessive tension is not placed on the wires.
6. Remove the water pump and take it to the shop bench for futher work. At that time, the water pump can be split by removing the remaining bolts holding the two pieces together.
7. Using a harmonic balance puller or similar, pull the fan pulley off the end of the shaft.
8. The shop manual indicates that the bearing should now be removed from the housing using a special tool. I have found it easier if the impeller is removed first, then the bearing pressed out, however take care not to damage the impeller or vanes.
9. Clean and inspect all parts. The repair guide suggests leaving the gland seal pressed in the impeller if it is still in good condition, as removal will most likely destroy the seal. Otherwise, if the seal is to be replaced, remove it from the end of the impeller and press on the new one.
10. Press the new bearing and shaft into it's bore, taking care to ensure that the grease hole in the bearing lines up with the set screw hole in the pump housing. Once in place, install the locking tab and set screw to hold the bearing in place.
11. Press the impeller onto the end of the shaft. The end of the shaft should be flush with the allignment face of the impeller when properly installed (see X in the diagram above).
12. At this point, I you can go ahead and pump some high-temp grease into the bearing while rotating the shaft to ensure good coverage. Make sure you use a grease with a high melting point.
13. Press the fan pulley onto the shaft so that it's alignment face is flush with the end of the shaft (see X in the diagram above).
14. Install the new gasket between the pump housing and mounting plate and install the two bolts holding the two pieces together. Do not overtighten. The shop manual suggests around 10 foot pounds of torque.
15. Install the new gasket between the mounting plate and engine block and install the four bolts that secure it to the block.
16. Re-install the upper and lower radiator hoses. If the thermostat housing was removed from the pump housing, replace the housing gasket and thermostat first.
17. Re-install the fan belt and adjust so that there is approx. one inch (1") of deflection present midway between the fan pulley and crankshaft pulley. Do not overtighten as that will cause premature bearing failure.
18. Fill the radiator with water until level with the top of the radiator fill cap. This should take approx. 3 gallons of a 50/50 water/anti-freeze mixture. Make sure that the anti-freeze used is rated for diesel use.
19. Run the engine until warmed up and ensure that there is water movement in the radiator. This may take several minutes to allow for the thermostat to open. Check to ensure that no leaks are visable.
20. Turn off the engine, top up the fluid level if necessary, visually check for leaks, then replace the radiator cap.

Tips:

• The locking tab that comes with the repair kit can cause some grief. There is very little clearance between the top of the bearing set screw and the inside of the belt pulley, so this tab can have a tendancy to hit the pulley if not bent over just right. A pair of snips can cut it down a bit, making a tab on the front, which is not only easier to bend over, but also allows more clearance for the pulley.
• High temperature grease must be used on the water pump bearing. It is easier to initally grease the bearing before pressing on the fan pulley, allowing the grease to be applied while turning the impeller to spin the shaft.
• Make sure the lower radiator hose does not come in contact with the fan belt, as there is very little clearance down where the hose attaches to the radiator and bends upwards. After installing the fan belt, check the clearance and adjust the position of the lower hose if necessary.
• If the fan pully does not press on the water pump shaft tightly, there is the possibliity of it slipping or even working it's way off. To prevent this from happening, a couple drops of permatex "Sleeve Retainer" on the shaft and pully should lock it in place (can be found at NAPA and other part stores).
• The thermostat I used was a Stant Superstat P/N#45758.