Can someone tell me if the bearing shaft assembly on the 496sea water pump should have a inward/outward movement at all? I have mine reassembled and there seems to be approx 1/16-1/8" of movement in and out. Never checked the old one before dissasembly..
Rear oil seal, tolerance ring and retainer/seal are new along with the housings!

That is how mine failed. I think mine got up to 1/2" axial play. I don't there is much when meeting spec I would say 1/8" is on the high side. Mine was so much the serp belt would slip off.

Thanks twanger, I've looked to see if there are any tolerance specs out there somewhere but no luck so far.
May live with it and see what happens.

I dont recall any movement in and out on a sea pump, just the power steering pump.

Do you have the brass pump? There should be no end play in it at all.

Yea the wonderful high tech Merc brass pump for the 496HO.

There should not be an 1/8" end play in a fully assembled pump. If you have that much play, take the pump off and check internally, somethings not quite right.
Best Regards,
Ray @ raylar

Raylar-what is the answer to this? Is there an upgrade to this pump? I have a single engine boat and carry a pump ready to slap in when something goes wrong.

The end play in this pump could actually a combination of the bearing and shaft fitment as well as some from the wear on the impellor to the back plate of the pump impellor housing. If you have a bearing going out that is creating a fore aft excess play you've got to take the pump apart and check the bearing and shaft. If the impellor is worn into the back plate with deep grooving then a machine shop can mill the back plate flat again and you can install a new impellor. You can also check with the guys at R&R performance in Lake Havasu Arizona as they make a new impellor and stainless endplate replacement kit for this pump that can save most of the worn pumps. Its cheaper than buying a new pump and a bit more durable!
Good Luck.
Best Regards,
Ray @ Raylar

I "upgraded" my 496 water pump with the R&R kit a couple of years ago due to deep grooves in the brass and their stainless end plates are holding up really well.