My expierence with the Hayward cartridge filter (model CX-1250) head o-rings has been quite frustrating. The problem is that the large o-ring that seals the head to the lower body will stretch and fall out of the channel that it is intended to stay in while placing the head on the body. In addition the o-ring is hidden under the black threaded hold down ring so there is no way to hold the o-ring into place or guide it into position. I have replaced this o-ring a number of times at the cost of about $20 each. Most of them only last a few months before they are so stretched out that they will not stay in the channel. Adding to the frustration, finding the replacement o-ring has not been easy. Local pool supply shops do not carry my particular o-ring in stock and finding them on the internet is possible, but a bit confusing. A reliable source for me has been Specialty Pool Products

THE SOLUTION... After buying a number of these o-rings, I found a solution that will allow you to continue using the stretched out o-ring without too much additional effort. Here is picture of the unit we are talking about. I suspect that this problem is not limited to this make or model of filter units, so this may work for others as well.
Hayward CX-1250 above ground cartridge filter unit:

By removing the ring molded into the head that retains the black threaded ring, you can pull the black ring up and out of the way in order to hold and guide the o-ring into proper position to seal into the body. This was easily removed using a wood rasp/file. I was able to grind off the retainer in just a few minutes with the rasp, but first, the black ring was easily removed by using a large screw driver to pry the black ring up and over the retainer. (sorry, I don't have a before picture here.).

Now, with the retainer removed, the black ring can be pushed up and out of the way so you can guide the o-ring into position when placing the head onto the body. This may require a bit of effort to "squish" the stretched out o-ring into place. You need to work the extra length (as seen hanging to the left here) into the channel by working the o-ring in while placing some down pressure on the head.

Finally, once the o-ring is in place and the head pushed down into the body, pull the black threaded ring into position and turn it down to secure the head just as before.

Author: dchafee
Article Date: 07/01/2006

Resources to Help You Fix Your Stuff Clearance Sale Blowout, Up To 40% Off

Didn't find what you were looking for?
Try searching or posting a question in the HowToFixYourStuff Forum.

READER COMMENTS

Posted by: Jaylen at 2011-07-07 08:37:16  
Gosh, I wish I would have had that information erailer!

Posted by: RC at 2011-04-20 19:25:52  
I put my o ring in the freezer for ten to fifteen minutes which contracts the elasticity. Put it back on and it was good to go. By the time it warms back up and expands, the seal is already in place. I got the idea from someone who said put the o-ring in a bowl of ice.

Posted by: [anonymous] at 2011-04-10 06:49:21  
You can also buy an o-ring from many Ace Hardware stores that is 1/2 inch less in diameter than the filter slot diameter. I use a 1/4 inch thick X 9-1/2 inch I.D. o-ring for my filter which has a 10 inch diameter slot. It fits more tightly and does not go out of shape so easily. Lubricate the o-ring with a little vaseline before installing it for an easier fit. Vaseline is also a good preserver of rubber products.

Posted by: [anonymous] at 2011-04-05 06:12:07  
You can also buy an o-ring from many Ace Hardware stores that is 1/2" less in diameter than the filter slot diameter. I use a 1/4" thick X 9-1/2" I.D. o-ring for my filter which has a 10" diameter slot. It fits more tightly and does not go out of shape so easily. Lubricate the o-ring with a little vaseline before installing it for an easier fit. Vaseline is also a good preserver of rubber products.

Posted by: [anonymous] at 2008-06-10 14:50:32  
You can also measure the diameter you need to fit and cut the o-ring with a razor blade and fit it back in. You need a little finesse to put the cover back but it works until you can find a replacement

Posted by: FixingStuff at 2008-06-10 14:50:09  
Yes... as the previous reader commented, you can actually cut the o-ring and remove the excess length. I have been using the same o-ring for over a year now by doing this. Just make sure to leave it long enough so that the ends still meet once placed in the groove. Believe it or not... it does not leak a drop using this method. Regards.

Fun fact# 47