[Joe K]

There have be a whole *hitpot of "aftermarket" Model A pumps made. Some of these are "pretty close" to what Ford originally provided.

I've seen differences in the front bearing as you're finding. With the needles/collar they work fine. With a set "leak proof pump" bearing such as you're trying to use perhaps not so much.

And even from Ford there were "varieties." Some have mentioned the "early" pump which has a very small hole on the underside. Then Ford kind of stuck to a stuffed packing pump with a press-in bronze front sleeve - no needles. Then Ford produced the "more typical" stuffed packing pump with the most common sprung sleeve and needles. Then Ford had available (past Model A production) a "replacement" pump which embodied the V8 type impeller/seal and a bronze sleeve at the front.

I have two "tubular" water pumps - these were used on the Baldwin Gleaner (driven by a Model A Ford engine)

And there were others. Perhaps more than can be counted or perhaps "accounted" for. One of my oddballs has a thin metal cover about where today you would put the green leather splash cover on a more typical pump.

I suspect Model A water pumps were the "most commonly changed" Model A component. Almost like "I want to work on my car this weekend maybe I'll change the water pump?"

Were this mine I would retrograde back to the standard spring bushing and needles. Check out Vince Falter's water pump page - or listen to Tom Petty for relaxation. There have been some significant diameter variations on water pump shafts provided for replacement. Something about 4 to 5 thou small - which affects both bearings and seal.

Joe