How to select better replacement bearings for a pool pump motor

I would like advice in selecting the right bearings for a pool pump motor.
About two years ago, the KBC Korea 6203D bearings that were removed were not the original bearings on this Max-e-Glas II pool pump with an AO Smith QC1102 square flange 48Y 1.0x1.65HP 240 volt single phase induction motor.
I had replaced the Korean 6203D bearings with USA NSK 6203V bearings, but even they didn't hold up as well as I would have liked.
The US Seal PS-201 pump seal was replaced in both instances, and no evidence of water leakage is apparent (no white crud on the bottom of the motor).
What bearings would you use that may hold up better under the circumstances?
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On Sat, 5 Nov 2011 05:57:26 +0000 (UTC), worker bee

NSK is a Japanese company (Nippon) and the bearings have been made in China since the Clinton administration but that aside. Is this a shielded bearing (metal race guard) or a sealed bearing (plastic race guard). You want a sealed bearing. Other than that there are lots of grades of 6203 bearing and you can pay anything from a dollar and a half each to close to $20 if you buy them from the wrong store. I am not sure there is actually a whole lot of difference. I bet 99% of them still come from China and may all be made by the same guys.
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On Sat, 05 Nov 2011 02:13:17 -0400, gfretwell wrote:

This is interesting data.
I have the two bearings in my hands. Guess what?
One has molded on the rubber seal at the 12, 6, and 9 o'clock positions: * NSK 151 6203V USA where the tiny 151 (date code?) seems to be stamped.
The other bearing, unexpectedly, has all four sets molded: * NSK 800 6203V China where the tiny 800 is molded in (verrry small!)

I do not know.
The black rubber (seals?) on each side are visible. I do not see any metal or plastic shielding on the outside. Do I need to pluck out the black rubber seals to see below to answer your question?
Googling for the difference between a seal & a shield, I find: http://www.dynaroll.com/shields.asp
Which says "a shield (non-contact) or seal (contact) retains lubricant and prevents contamination from entering the bearing raceways".

I see that!
Googling, I find the following types for 6203 bearings: 6 = metric sized, single row, deep groove 2 = light duty (i.e, 40mm OD, 12mm thick) <== I think I can go larger 03 = 17 mm bore diameter <== this is a critical dimension
These seem to be the designations I can decipher so far: D = molded Buna-N rubber lip seal with a steel insert which provides maximum protection against contamination; however, the high pressure of the lip seal itself results in greatly increased torque and friction losses that can cause heat build-up in higher speed applications. The seal material itself is rated to a maximum of 250 °F S = same as D except it's non contact DD = same as D but double shielded M = brass cage V = single, contact, nitrile rubber seal (keeps fluids out) Z = single, staked, non-contact shield of 300 series stainless steel. LL = ? seems to be the same as 2RS ? NR = snap ring and groove RS = single nitrile rubber seal TS = glass reinforced teflon giving good contamination protection VV = double non-contact seal ZS = same as ZZ but retained by a snap wire TTS = same as TS, but double shielded ZZS = same as ZS but double shielded ZZ = double, staked, non-contact, 300 series stainless steel shields ZZA = removable shield 2RS = double nitrile rubber seals DDU = double contact seals (apparently similar to 2RS) 2RSC3 = ?
SOURCES: http://www.gizmology.net/bearings.htm http://www.dynaroll.com/shields.asp http://www.dynaroll.com/selector.asp http://www.bearings.machinedesign.com/BDEList.aspx http://www.top-bearing.com/news/?p@7 http://www.ntn.ca/pdf/2200/dimcodes.pdf http://www.mcmaster.com/#6203-ball-bearings/=espnpe http://www.motionbrgs.com/basic_brg_info.htm http://www.skatebearings.com/6200-series.htm http://wetheadpumprepair.com/6203-ll-electric-motor-bearing / http://www.nmbtc.com/bearings/part-numbering.html http://www.skf.com/skf/productcatalogue/calculationsFilter ? lang=en&newlink=&prodid=&actionlc1
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O

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