How To Rebuild a Water Pump
Learning how to rebuild a water pump is a great project for any classic car owner who wants an original-looking and better-performing component. Over time, internal wear requires a complete overhaul. Doing this yourself refreshes the housing while saving the original part. By installing fresh internal parts, you will keep your cooling system running smoothly on your next trip.
Pump Disassembly
When you start the teardown of your original pump, work slowly to avoid damaging the housing. To begin the teardown, you must first remove the hose nipple. Next, snatch out the six bolts that secure the back cover and lift the cover off. With the cover removed, look at the impeller inside.
The blades will tell you whether you have a standard clockwise rotation or a reverse counterclockwise rotation. Water pumps fall into these two different classifications. They utilize two different impellers depending on the rotation direction.
If you put the wrong one in your setup, you will run into cooling problems. Now, use a press and a bolt to push the shaft out of the hub. Next, grab a deep wheel socket. Use this socket to slowly push the impeller and shaft assembly out of the housing.
Cleaning And Housing Inspection
Before assembling your new parts, you must make sure the housing is in good shape. With your housing completely empty, toss it into a blaster for some cleanup work. Remove all that old gasket material. This is when you can remove the old gasket material and check the housing for cracks. If you do not have a blaster, a wire brush and some solvent will work. This alternative method is slower but also effective.
Installing The Rebuild Kit
Rebuilding the internal components of your water pump requires high-quality replacement parts. For the rebuild, get a kit from Zip Corvette products. This kit includes a new shaft, impeller, front hub, and bearings. Before you press any new parts into the empty housing, spray the inside with WD40. Applying this spray helps prevent galling during reassembly.
The longer end of the new shaft is grooved. Press this grooved section into the housing, and when installed, the bearing race part should be flush with the housing. On the other side, use a socket. This socket will push the new seal over the shaft. You must then switch to a bigger socket to get the seal bottomed out against the housing flange.
Next, you need to install the fan hub. In the press, position the water pump assembly so that the shaft can be pressed into the hub. Measure the distance from the front of the hub to the inlet. This distance should be 5 and 5/8.
Now press the new impeller over the shaft. Make sure the blades do not touch the housing during this step. Using a feeler gauge, measure the clearance. You need from 10 to 13,000 clearance between the impeller blades and the housing.
Final Assembly And Testing
Replace the cover on the housing. Once the cover is in place, make sure the shaft turns freely.
The entire rebuild only takes about an hour’s worth of work. You are now ready for paint if that is in your plans. Either way, you have achieved a better-performing water pump that maintains its original look.
