When to replace motor bearings, and whether to replace both

[PeterPan]

Hello fellow pool lovers/haters? Love the water but hate the constant maintenance right? (Its always SOMETHING).

Anyway, I've been down this road of considering the replacement of noisy bearings before. Always on a budget though, I "considered" for way too long last time. I just let the motor whine louder and louder for years until it finally seized. By that time, the added friction caused so much heat build up that the fan on the motor shaft had melted, and the poor 18 year old motor's long screws were so badly stuck, I could only save 2 out of the 4. So I decided to just replaced the motor with a new one. the replacements were only about $130 at the time, and AO smith USQ1102 (pretty common I think). All was well for 4 years until a couple weeks back when the impeller mysteriously broke. So, I took the pump apart, and not finding any smoking gun of a foreign object in there, I simply replaced the impeller. Unfortunately, I probably disturbed the carbon/ceramic seal, because 2 weeks after the repair, the motor is beginning to whine. Not badly, but its starting. Well I really have become spoiled by the quietness of the new motor. I'm a little discussed I only got 4 years out of it, but like I suggested, I probably caused the problem. So I plan to replace bearings this time, having bought all the tools from the last attempt. So here are my questions:

1. How long is it reasonably safe to wait before repairing. I'm not being lazy but its the hottest part of the year and putting it off a while would be nice. But then again, this motor runs longer than most (at least 6 hours or more), and must run during the sunlight hours. In addition to cleaning (Kreepy Krauly) it also pumps water through solar panels on the roof to warm the water.
2. From this and other forums, it seems most bearing problems are caused by water leaking from the seal, which mainly affects the front bearing. Is there a sure fire way to figure out which bearing is really causing the problem? Since they come in pairs, and being the motor is only 4 years only, Am I being too much of a cheap skate to just do the front bearing (and change the seal too of course!)

Thanks for any advise!

 

[thebombardier]

Usually just the front bearing is shot, but bearings are relatively cheap and you're in there anyway so why not replace both?

As far as when, ASAP. The seal going out not only ruins the bearings but is why the motor rods are so hard to get out. The longer you wait the harder it's going to be to pull everything apart in the first place. Plus you risk water leaking into the windings and taking those out as well.

 

[PeterPan]

Usually just the front bearing is shot, but bearings are relatively cheap and you're in there anyway so why not replace both?

As far as when, ASAP. The seal going out not only ruins the bearings but is why the motor rods are so hard to get out. The longer you wait the harder it's going to be to pull everything apart in the first place. Plus you risk water leaking into the windings and taking those out as well.

Yeah, thanks. That's kind of what I expected to hear.

Funny, today the pump came on and it was noticeably quieter. I guess a "whinny" bearing noise is bound to vary some, but is it wishful thinking that it might have been a temporary leak that remedied itself once the seal "re-seated" itself some? Recall it did start a short time after my impeller replacement, which I'm sure disturbed the seal. And not being lazy here, but the job is a pain in the neck at best. Any chance I could snake in the tube from a can of that magical WD-40 through the gratings at the bottom, and hit the bearings just right? I guess they are supposed to be sealed bearings, but they can't be THAT well sealed if they let water in. Anyone ever do this and get it to quiet down for another season?

Point taken about the water messing up other parts. I'm sure if water is dripping in there, any remedy like this will only last a couple of days. But maybe I'll be lucky? If water is continuing to leak in, wouldn't I see it dripping out the bottom vents if I watch for 10 minutes?

I almost wish these motors came with shafts maybe an inch or so longer, and some kind of extender for the mounting holes. It seems like having the motor shaft right up against the pump housing was not the best design choice, given how common this problem seems to be. But I digress... ;-)

 

[thebombardier]

We don't even mess with WD-40 in my shop. Get a real penetrating oil like B'laster. That'll unfreeze any motor rod as long as the aluminum hasn't corroded around it.