Help needed with refurbishing old pump motor

gustafson

Well-known member
Jul 20, 2015
89
Houston, TX
#1
So I acquired a used Magnetek 2HP B985 dual speed motor to replace a failed B855 on my 2HP Challenger pump. Some pics attached.



The motor came attached to a pump and filter as shown in the pics. I'm having trouble removing the center screw on the impeller, which seems to be locked up by corrosion. I'm assuming it is reverse threaded and have been hitting it with WD-40 to loosen it up. Let me know if I should do anything different.

Also, when I popped the rear cap to access the shaft, I noticed that the rear end of the shaft is pretty corroded (pic attached), and while the shaft turns freely by hand, it just feels like there's a little grit somewhere - maybe I'm imagining it.

I'm planning to replace the shaft seal for sure, but was wondering if I should replace the bearings too while I'm at it. How big of a pain is it to take the motor apart and replace the bearings? Or is it OK to run the motor as is for some time and replace the bearings at a later time?

Thanks for your input!



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Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,922
SouthWest Alabama
#2
You're right that the impeller screw should be left hand threads. Just keep after it gently until it loosens.

I it were me, and I were rebuilding it anyway, I'd go ahead and replace the motor bearings. Especially since you're feeling some 'grittiness' when rotating them.
 
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gustafson

Well-known member
Jul 20, 2015
89
Houston, TX
#3
You're right that the impeller screw should be left hand threads. Just keep after it gently until it loosens.

I it were me, and I were rebuilding it anyway, I'd go ahead and replace the motor bearings. Especially since you're feeling some 'grittiness' when rotating them.
Thanks for the advice! How easy (or hard) is it to replace the bearings? Any do's and don'ts that I should keep in mind?


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gustafson

Well-known member
Jul 20, 2015
89
Houston, TX
#4
You're right that the impeller screw should be left hand threads. Just keep after it gently until it loosens.

I it were me, and I were rebuilding it anyway, I'd go ahead and replace the motor bearings. Especially since you're feeling some 'grittiness' when rotating them.
Ok, success getting the impeller center screw out, but not before stripping the screw head, drilling into it, and finally tapping on it with a screwdriver using a rubber mallet. I think WD-40 followed by knocks with a mallet was the most effective maneuver.

As for the bearings, I think I might give it a pass for now, because most of the screws and bolts on the B985 appear to be rusted in, and taking them out seems next to impossible.

I am now stuck getting the existing motor off my pump. I was able to get the impeller off, but the shaft seal part with the spring is stuck pretty tight on the shaft and I'm unable to twist it off by hand. If you or anyone knows a hack to get that out, it will be greatly appreciated.



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Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,922
SouthWest Alabama
#5
It's actually not very hard to replace the bearings once you get the end bells off. However, given the possible corrosion on the bolts, I understand you're being hesitant to tear it apart.

You'll most likely have to remove the seal plate from the motor in order to get the ceramic seal part out. It presses out toward the impeller end and is usually stuck in there pretty good.

Now if the rotating (spring) part of the seal is stuck to the shaft you can just pry that off and then clean up the shaft. Try not to scar the shaft when taking it off. You can try to loosen it with some WD-40 if you'd like.
 
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gustafson

Well-known member
Jul 20, 2015
89
Houston, TX
#6
It's actually not very hard to replace the bearings once you get the end bells off. However, given the possible corrosion on the bolts, I understand you're being hesitant to tear it apart.

You'll most likely have to remove the seal plate from the motor in order to get the ceramic seal part out. It presses out toward the impeller end and is usually stuck in there pretty good.

Now if the rotating (spring) part of the seal is stuck to the shaft you can just pry that off and then clean up the shaft. Try not to scar the shaft when taking it off. You can try to loosen it with some WD-40 if you'd like.
Thank you so much for the pointers. It's the spring part that that I'm struggling with at the moment. I tried prying it out with my hands but no dice. I'm hesitant to use pliers as the outside of the seal doesn't look solid. Some kind of tool that allows pulling the seal element out would be ideal. Wasn't sure about using WD40, so thanks for that tip!

Will also try tearing down the replacement motor to access the bearings. I wasn't even able to open the screws on the capacitor casing, so I'm not too optimistic, but we'll see [emoji28]


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Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,922
SouthWest Alabama
#7
If it feels like the screws are going to break off when you try to remove them, it's probably best to leave them alone. It doesn't take a lot to break them off, so be careful.
 
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gustafson

Well-known member
Jul 20, 2015
89
Houston, TX
#8
If it feels like the screws are going to break off when you try to remove them, it's probably best to leave them alone. It doesn't take a lot to break them off, so be careful.
Thanks for the heads up. That's kind of what happened on the impeller center screw, the head just gave in, and I was extremely lucky that the mallet routine saved the day. [emoji26]


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gustafson

Well-known member
Jul 20, 2015
89
Houston, TX
#9
I ran into another issue. I was trying to unscrew the bonding post (in preparation to test the motor) and the head of the screw broke off leaving the stem inside the motor end cap. The broken stem appears bonded to the threads via corrosion, so removing it is likely impossible. Is there any fix for this?


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gustafson

Well-known member
Jul 20, 2015
89
Houston, TX
#10
Resolved the bonding post issue by drilling into stuck shank and tapping threads so I could use the bonding post screw from my failed pump. Worked a charm, and the pump is up and running now. I'm calling it my Screwshank Redemption [emoji28]The only issue I have now is that I turned on the pool & spa lights to check circulation, and both lights went on the fritz within minutes. No idea what happened, but I need new lamps [emoji19]


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