I've replaced the long-snout water pump on my 364 Nailhead with a shorter pump, and finally found the right pulley to mount to the pump. Problem is, I'm still about 1/8'' off in getting the crank pulley and the water pump pulley to line up perfectly. Looks like I need to shorten the impeller shaft just a bit to get things to line up. How do you go about that?
There's a very good chance the rebuilt water pump didn't have the fan/pulley hub pressed on far enough by the rebuilder. I played hell with this same problem on a small block Chevy water pump. You'll need to get at the impeller from behind, and support the SHAFT itself, and press the hub down further onto the shaft. If I remember correctly, doesn't the Nailhead have an open water pump? I mean, the back isn't covered like a Chevy. Access to a shop press makes this easier, but you can probably do it the old fashioned way (hammer). Just make sure you are supporting the shaft itself, and nothing else. You need to keep the shaft stationary, and press the hub down over it. Not a big deal if you realize the fix can be this easy. It took me days of stress trying to figure it out on my Chevy, and now that I know about it, it's one of the easiest fixes in the world. (I even know one restorer who MILLED the back of a Mopar pump to get it to fit right!) We just ***ume the rebuilt or even new-built water pumps are going to be correct. -Brad
What all you have running off the belts, just the water pump and generator. You don't have A/C or power steering on? If your just running the basics be cheaper to shim it up. If the later, probable get the shaft turned down by a machine shop, or on a lathe if you have access to one. Glad Brad pointed that out, rebuilt stuff can be f-up also.
Thanks for the responses. The nailhead pump is open at the rear, so I could access the shaft. And I have a press, so I could give the hub a nudge. If that doesn't work I could break out the shims.
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