Sealing an "O" Ring

I used the "O" ring lube and it did nothing. The pvc sealant was the only thing that slowed down the dripping.

I can not see and knicks or cracks and the leaking is almost all on one side.....very small drip, but drip none the less.

The "O" ring is exactly the same size as the one that wsa there before ( in diameter).

It is 6" diameter.

You want the same diameter but slightly thicker.....

Andy,

I have that thing so super coated in teflon tape, silicon and whatever else would harden up....I doubt I can find the O ring.

The tank fittings , top and bottom look worn. I suspect the lugs are worn out and being that is is molded plastic, the whole top section should be replaced.

Thank you for the input though.

Pics would help

I have the whole thing screwed up tight right now and allowing this little drip to contnue. I would like to hold off taking the top back off until I am ready with another plan.

The ring just sits snug around the out peremeter in a little groove.

The top section with the turn dial handle assembly locks down on top of that, lines up wityh a small hole and a pin drops in to make sure the thing doesn't move when you manually move the lever to go from filter to backwash .

The ring is about 1/8" thick x 6" diameter.

I'm wondering if you're over tightening it. If you had a fresh ring you could try it at a loose fit and progressively tighten it until the seal was formed.

I assume you've checked and threads are clean and not cracked. You can also turn the ring on itself and make sure it is crack free. You should be able to get a seal if the ring is the correct size and you're using the proper lube. I'd leave the plumbers putty on the shelf.

good luck

O rings are mostly all standardized. It sounds like yours is an AS568-258. It's nominal dimensions are 5.985" dia. and 0.139" thick.

There is a tolerance to the diameter. If your groove is not well contained, the particular o ring may be a little too big or too small. If it's too small, stretch it out a little and fix it in place before it reverts to it's original size. If it's too big, cut out a small piece, and refasten it with rubber cement.

They also come in different materials and durometers.

Check McMaster-Carr, at WWW/mcmaster.com for a selection.

"O rings are mostly all standardized."

There are a few people in the aerospace business that might argue that point with you.

Tonight I noticed the filter is leaking with the putty . I dismantled it and wiped off the putty off. I then put a good layer of O ring sealant and lube over the ring and reinstalled.

I have re-plumbed somewhat and noticed that there is NOT a full load of water coming in as yet. I need to adjust so that there is more water meeting the fliter.

Tonight I will let the water level increase higher so that when I start the filter, there is no cavetation .

I do remember this happening years back and when I installed the new O ring, it actually stopped laking in a day or so.

Other wise I will look into taking off a touch of the plastic locking mechanism ( lugs) and letting the top section turn a little more. However, there is a hole in the top section that alligns with the filter section so a pin can drop in and keep the top from turning.

The entire top section when seated only turns about 2-3 inches before locking. there are no threads just some lugs.

I'll take pics tomorrow afternoon in the day light.

Thank you all so far.

Bon Soir

I'd guess the O ring isn't being compressed, lapping down the appropriate face may solve the probleb by allowing the parts to screw down a bit further.However such a solution requires a good understanding of the mechanical arrangement and a steady hand with a flat bolck and fine abrasive paper.
I have done similar repairs on washing machine solenoid vlaves where the plastic has moved with time.
Alternatively cut another ring from rubber sheet to use as a replacement or aditional ring (same terms and conditions apply)
Del

Has it sealed OK in the past, but now started leaking, or has it never been right?

What is design pressure? Is the actual pressure below this?

Codey

It did leak a few years back . I used a rubber mallet and knocked the top section just a bit and it closed up.

Now I see the old "O" ring was broken so I replaced it with a new one. It leaked last night no matter I did.

I am wondering if the entire top is just a tiny bit out of position??? It just will not stop leaking water.

Difficult to judge without seeing it, but it looks like you can only tighten it a certain amount (till the pin aligns with the hole, and perhaps a mechanical stop) and if it's old and worn maybe it needs more. In that case possibly a thicker O-ring would cure it.

And the pressures?

Cheers........Codey

I find it odd that the old one was "broken".

If it is only exposed to water, then consider installing a softer o-ring (I would try this before trying a larger x-section o-ring).

If the o-ring is getting hard, then sounds like either a temperature or chemical compatibility issue. If this is the case, you will need to find a different material for your o-ring.

please cheack hair crack , in the area where the leak come from

From your description/picture, I get the impression that this is a typical sand filter like what is used for swimming pools. When you removed the backflush valve it is possible that you caused the pipe that the runs from the center of the valve to the bottom of the filter to shift upward. This is common. The valve usually has another seal where the pipe enters, and this drags the pipe up through the filter medium when you remove the valve. When you reassemble it, the pipe is now too long and prevents the valve from seating properly, and you are not getting proper compression on the o-ring.

Another thought - If these pats are plastic, have any of them distorted slightly?

That, also could cause your problem after they have been disturbed .....

Is the o ring a replacement from the manufacture or a generic from a local supply house. In the past, I have found that generics can have a molding flash around the inside and outside. Under high magnification, the flashing can be seen. Sealing on the face surfaces isn't a problem but if you require a side seal, it's hit or miss. Seek out a mainstream brand like Parker or specify a mil spec o ring, which is buffed so there is no flashing left. First contact the manufacture. They've probably heard it before.

To add to this good response, such O-rings are also described as "quad" rings, having an X-shaped cross-section with rounded corners.

These "quad rings" use the same numbering system as National O rings do, just preceded by a 4.

Here is a trick that works with old as well as new o-rings:

Use Teflon tape to wrap the o-ring totally with several layers of tape.Then install normally. 99% of the time this works if its caused by a small tolerance deviation of the o-ring.

I have used this method successfully on sliding o-rings in a cylinder, simply put the Teflon tape in the groove UNDER the o-ring.Works as good a a new o-ring.

Thank you.

I tried that and it seemed to work....still had a small leak.

So I coated the entire groove, tape and O ring with some of that clear sealant , not sure of the brand.The leak is still there but now down to a trickle.

nm

If the tank is old it may have 'grown' a bit from the constant pressure and now the two grooves for the O-ring in the opening at the top and in the lid don't line up anymore.

i'd try using a small layer of good Silicone RTV in the O-ring groove, install the o-ring, and add another thin layer of Silicone RTV, and then attacehd the top.

Try cutting out small pieces from a aluminium pop can and inserting them on top of the lugs as you are tightening the top down. That would put a little bit of extra pressure on the O-ring.

You might also try a good quality clear silicone in the grooves first, then lay the O-ring in the silicone and then tighten down the top. I would wait an hour or so to let the silicone set up alittle first before turning on the water.

Rescue

Try to find a food grade silicone. It will work but getting it back off will be interesting.

3-M 5200 will seal anything as long as you don't ever want it to come apart again.

Thank you all.

The filter is old and the plastic lugs are worn too.

The grooves did leak on one side.

The teflon tape and silicon on top, then the O ring seemed to cut the leak down to a very , very small livable water loss.

I am reasonably sure that the two joining halves are worn and possibly warped.

A new filter is probably on the wish list sometimes this year or early next.

All ideas were tried and I am happy to say that a combination of them have fixed my problem as well as it needs fixing.

Thank you all.

Thanks for the update, usually once someone gets an answer they just take off and are never heard from again.