PROJECT 51: Water pump rebuild. Typically, when rebuilding an engine with lots of miles on it, the water pump is replaced without a second thought. For a Chevy 350, the prices I found range from around $30 to $80. For the MG, a professionally-rebuilt unit (the new ones they make are NOT recommended) is $250, and that is using a cleaned-up original sixty-something-year-old cast iron body.
When I took my pump off the car and cleaned it up, I discovered that it had a bronze body, and after some research, I found out that it was an aftermarket unit made in the 70's, and is highly desirable because the bronze won't corrode the way cast iron does. It also has a six-blade impeller, where the stock unit has only four, and therefore moves more water.
I held onto the improbable hope that I might be able to reuse it, but although the impeller turned freely, there was obvious "cogging" in the bearings, probably caused by corrosion. When I dismantled it, I could see that water had leaked past the seal and collected between the two open-sided bearings, causing rust in one spot in the rear bearing, resulting in that cogging.
The bearings are a common metric size, and I could find several sources for those, but the seal was a different matter. Even if one of the MG part-supply houses had sold a rebuild kit (which they don't) it would be unlikely to fit my aftermarket pump.
I took the old seal assembly out of the pump, but without a manufacturer and part number on it, it took a good deal of online searching and several phone calls to finally locate a company that could supply this type of seal, and then some e-mailed photos to narrow the search to a part number.
Many thanks to Kara Gardner of "Champion Hi-Tech of Oklahoma, Inc." for her diligent help in finding a manufacturer for my seal!
A slight modification to the hub of the impeller was required to use the ceramic mating surface of the new seal, but that will produce a better and longer-lasting seal against coolant leakage.
After polishing the bronze body for show (the original would have been painted MG-red) the new bearings and seal components were assembled, and the unit is ready to be attached to the engine.
Total cost to rebuild: $52.
|Water pump still attached to engine.|
|Old and new bearing.|
|Old and new seal,|
|Seal seen near seal-mating surface of bronze impeller.|
|Turning the impeller to fit the new ceramic mating surface part.|
|New ceramic mating surface part in place.|
|New seal in place.|
|Rebuilt water pump ready for installation.|