Yes it's a press fit. Tolerances are off on one of the 2 pieces

 

Just a (dumb) thought...but would pressing back on with Loctite 680 retaining compound be a valid repair?

 

Not dumb at all. A press fit with that retaining compound it’s never coming off again!

 

What fan and fan clutch are you running?

 

I have a 17" Derale fan and Hayden clutch, CW rotation. Everything is new and operated great until this happened.

 

Never seen it happen. But I've always run reverse rotation components on a foxbody.

 

Yup, ****ty press fit right there. Man that sucks. I can't really think of a way to fix it other than get it in the right spot and put a few tack welds on it.

 

I know most people would say to just get a new water pump, but this one is new and my budget is gone. I'm going to use the Loctite and tap a hole for a set screw. It should be better than a factory interference fit.

 

With that retaining compound on it and it being a tight fit, once that compound dries the only way it’s coming off is if you heat it with a torch enough to make the compound fail. That compound is incredibly strong! I use to permanently attach rifle barrels with it and you either needed a torch or a 12 ton press to get the barrel off lol.

 

Dimple the shaft with a center punch also

 

Same thing happened to me a few years ago, same brand. Took out the radiator, and the fan. Was only 1 year/1500 miles old.
Went to an Edelbrock unit.

 

It seems to me with something that can potentially cause damage to property or person, there should be a snap ring or something to retain the hub. I will definitely check these in the future and tap the hub and shaft for a set screw.

 

Mark the shaft so you can tell if it starts to move if you tap it back on. You do not want the impeller to hit the timing cover.

This is a safety hazard which never should have happened. Considering this I would think about getting rid of it as opposed to try to fix.

I would not want it on my mind if it falls off again and hurts someone.
Even if does not hurt someone, it could wipe out the radiator and the fan which will cost a lot more than the pump.

 

I would go to the Manufacturer’s social media and post your pics. If they don’t have a SM account anywhere, email them with pics and say something to the effect of “hey, lack of QC caused some damages to my vehicle - can we talk compensation?”