Repairing Mag pump

yardboy · 08-09-2004, 06:15 AM

To anyone whose experienced problems with a Mag pump not starting after shutdown... I had this problem with an older Mag 7 I'd used as a return for two years and then hooked up to my RO/DI system. Figured out that the bearing housings were worn out of round (just plastic) allowing the impeller to bind on startup. Took a small ball of epoxy (the stuff we use to glue corals to rock) and dropped it into the worn out hole and wrapped the impeller in plastic (grocery bag) to keep it from sticking to epoxy. Shoved impeller back into place, where the epoxy squeezed into the worn area. Did this on both ends of the impeller, reassembled the pump with plastic in place. After the epoxy set, (I waited an hour) took the pump back apart and removed the plastic. Epoxy had set and impeller freely turned. Been running for a week now, with many starts/stops and seems to be working fine. Less noisy too! If you need further details, just pm and maybe I can explain better. Shoulda took pictures. Darn.

kwjones · 08-09-2004, 09:03 AM

So, the worn out area isn't the impeller itself, but the housing that it sits in? I'll have to remember this one. I know the impellers are pretty cheap to replace, but the rest of the pump isn't.

Geoff · 08-09-2004, 02:37 PM

dang, i wish i had seen this before i left. i was just down there on St. George's Island i could have given you a mag 7 to do and take pictures.

i am still not clear on who is culprit. there is the black cap that the ceramic axel fits into, is it this? or is is the piece that the this cap fits into?

G~

yardboy · 08-09-2004, 05:49 PM

Should have come on by Geoff!

Yes, it's the pump housing area that the "axle cap" sits in. It was way out of round and apparently causing the axle to bind, as it wouldn't always start, and made noise when it did. I'll take it apart tonight and try and take a picture of the repair job. Glad I posted this, as I'm sure plenty of people have had similar problems, and it seemed to fix easily (with just the right size ball of epoxy and the plastic seperator so the cap wouldn't stick to the epoxy)

yardboy · 08-09-2004, 10:44 PM

Okay, got some pics:
1) pump housing, showing epoxy set in place
2) motor housing with epoxy in place on it.
3) pump impeller
4) impeller with plastic wrap so epoxy would not stick to impeller, just mold it.
5) pump reassembled with plastic in place
later housing was removed, plastic taken off, and pump reassembled. Hope you can understand. I seem to be "explanation-challenged" this evening. Darvocet might be the culprit.

Geoff · 08-09-2004, 11:16 PM

those pics are perfect!!

i know what i will be doing later.

G~

Doug1 · 08-10-2004, 12:06 AM

Darvocet can do that, but with enough you dont care as a rule

yardboy · 08-10-2004, 06:43 AM

I hope you haven't jumped on it too soon Geoff, as I might add that using too much epoxy is probably a bad thing. Could squeeze out and get in the way of something. Also, when you put the impeller back in place, try and aim it so that it goes back in its original position, and pushes the epoxy toward the worn out area. Frankly when I pulled the plastic off and put it back together I wouldn't have been surprised if it hadn't worked at all, being bound up by the epoxy, but then it didn't work anyway! I'll only gurantee that mine works, right now, for me!

Melissa · 08-12-2004, 09:25 AM

You know, I am really glad to read this. One of my mag 12 pumps siezes on me. The power went out for a few hours last night and of course the **** thing wouldn't start back up. Get out the wrenches. Take out the pump. Open it up. Pull out the impeller. Put it back in. Plug it in and lo and behold - it works again. It's really becoming irritating.

What brand of epoxy did you use? I have a tube of Zap glue. Yesterday I went to Home Depot and picked up some two part epoxy then was reading the instructions on the back - it says in huge capital letters NOT FOR AQUARIUM USE so I guess I got the wrong kind.

It seems as though I need to get a backup pump anyway just in case this doesn't work. Just don't want to blow another $100.

Melissa

yardboy · 08-12-2004, 10:02 PM

I used the same stuff I use for the corals. Had it so long not sure what the brand name is though. Green on teh outside, white within, turns white when you knead it together.

Your symptoms were exactly what I had. I'd used it for a return for nearly two years, only when I swapped it to my RO/DI that it started being used intermittently and began misbehaving. Working now. I'll see for how long.

Geoff · 08-13-2004, 09:37 AM

i figured i needed a very little amount, so i was safe when i tried it. it is hard for me to tell if it fixed my problem since all of my plastic screw binding posts that hold the cover on have broken off.

so far it seems better though. my cap holders were very worn.

G~

yardboy · 08-14-2004, 09:05 AM

Darn Geof, you sure mistreat pumps! Have you thought of trying to repair the screw posts with the epoxy? At work we often use a company called Belzona, who makes a prodigious number of different types of epoxy material, for all sorts of stuff like that. Last week I watched them repair a cavitation damaged pump with the stuff and it worked. (This was a pump with a 250 hp motor on it, so lots of pressure) The epoxy that I use for coral placement gets quite hard and sticks to plastic quite well. Sure it's the same stuff youhave. Can't hurt to try it!

Geoff · 11-07-2004, 09:29 PM

i just had another mag do this to me. so i tried another fix. this falls in the ghetto category.

cut off a very small piece of electrical tape and stick it to the end of the impellor cap. stick it together. the electrical tape conforms to the sides of the cap and holds it nice and tight. so far it is working great for me.

thanks yardboy for figuring out the initial problem!

G~