Technical 354 Hemi waterpump issue

The fan and pulley, still attached to the snout, came off my waterpump shaft while driving at highway speed. No bueno.

The snout is press fit onto the waterpump shaft.

I have three waterpumps here. Two of them appear to have the snout drilled for a taper pin, but none of the shafts are drilled. I've attached some pics.

It was an unexpected failure and I'm not sure of both the cause, and how to make sure it doesn't happen in the future.

Thoughts?

 

I ran into something much like this some years ago. The Customer had hand-built brackets for Alt, Power Steering pump and an idler pulley. None of them were dead square and in alignment with the pump pulley. The belt tension and harmonics actually walked his Pump Flange forward and Off the shaft of his pump. This I felt was from the forward angles and off set in his Fab work. Once corrected it never happened again as far as I know. Other than that one time I have never seen a Hub walk off a pump. I have however seen several pulleys fractured around the bolt holes.

 

I'm relatively confident in my alignment, but I'll definitely double check!

 

do you have a way to accurately measure the shaft and bore diameters? to check how much interference there is on the press fit

although since there is evidence of having been pinned in the past, it kind of makes one think there was a problem there, all along

 

There's visible corrosion on the shaft where the snout was riding, which makes me think there was an issue with that old snout.

 

As I remember it, both of his belts had telltale shafing on both edges of his belts where they were ridding hard on them. Something to look at.

 

The press fit was/is obviously gone, likely during the last rebuild for whatever reason. FWIW, I have never seen a pinned hub on these pumps.

 

Ok. That sounds good. Would it be beneficial to put some Loctite on the snout of the new one?

 

I'm not sure I understand your locktite question? Are you pressing a new fan hub on the existing water pump?

You should have a real tight interference fit between the two, and if you don't I wouldn't trust locktite to fix it.

 

There is a real danger of breaking the graphite seal inside if you attempt to reinstall the hub without fully disassembling the pump.
As ebbsspeed suggests, Loctite does not make up for lack of diameter.

 

Ok. All good information. Thank you.

 

I have a dodge 56 service manual that refers to driving the pin out to disassemble the water pump. I wonder if the pump has been rebuild in the past and the new shaft didn't have a hole for the pin.

 

Tap some threads in the hub, drill a corresponding dimple into the shaft and use a set screw to hold them together. Most likely both the hub and the shaft are now a little beat up from the loose fit and subsequent failure so use due diligence whether to repair or replace.