Leak in main drain pot

Esand323

Well-known member
Aug 6, 2018
85
Indianapolis
Hi all,

A few months ago I was brushing my pool when I hit the main drain cover pretty good. A few days later I noticed how much the pool had lost water and quickly found the leak down at the main drain. One of the screws that screws the gasket down to the main drain pot had come a bit loose. I then found out that the wrong screws were used when the liner was installed last year. Apparently, instead of using the typical Hayward screws that come with, the installer used a different set that had a smaller diameter but was longer. 3 out of the 8 were stripped and just spinning in place. Under one of these screws was where the leak was. I went ahead and replaced the 3 that were stripped with the correct Hayward SPX1039Z18 screws. I left the other 5 alone because they weren't stripped. I also put a bunch of Permanent Sealer on the screw before putting them back in. The screw with the leak still felt a bit stripped as it wasn't catching very well (better than before though), but the leak had stopped. So I didn't mess with it any more. One of the other new screws was also not catching well, but there was no leak there, so I left it alone. The third new screw was catching just fine.

All was good and the leak had stopped. Unfortunately, today I had a company close my pool up. When they blew out the water in the main drain, the amount of pressure seemed pretty intense. I was immediately concerned that it caused the leak to come back. After they left, I put some painters tape on the liner to mark the water level. 3 hours later, I had lost 1/2" of water. Even though it was only 55 degrees out, I went ahead and jumped in the pool. I took the main drain cover off and confirmed that the leak was back with some dye. This time, it's not leaking under the same screw, but it's leaking under one of the other 2 screws that I replaced because it was stripped.

I took the screw out, put on more Permanent Sealer and put it back in, but no luck.

What should I do at this point? I called the company that closed the pool and they suggested I try adding some sealer around the inside of the gasket and see if that helps. I was trying to think of some alternatives though. I could possibly drain the pool and have an entire new main drain pot put in. But the company I was working with didn't think they would be able to reuse the same liner and thought I would need a new one. I don't really want to have to replace a liner that is only one year old.

Should I look at getting a larger screw? I was thinking of maybe going back to the old "wrong" screw that was used. It's smaller in diameter but it's longer. I could wrap it in Teflon Tape and see if that works. If not, it looks like the SPX1039Z18 screws are just a #10 screw. So maybe I just find another #10 screw stainless steel screw that's just a little longer at my local hardware store? Or perhaps I go up to a #12 screw? I'm just concerned about using too large of a screw and cracking something. But right now I'm losing water at a rate of 4" a day. So if I can't fix the leak, attempting something that might crack the pot probably won't matter.

Lastly, I plan to call the original liner installer to see why they used the screws that they did, but it was an awful experience working with him. I doubt he will pick up the phone or call me back, so might not get anywhere there.


Here is what I'm talking about. The leak is either between the liner and bottom gasket or between the bottom gasket and the "body." I can't get a good look down there to see.
mbd.jpg
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,892
Central California
Way outside my experience, but I can imagine what the problem is (until someone that knows better chimes in). It's like roofing felt. You can drive a nail through it to attached the roof shingle, and the penetration through the felt won't leak because it's sort of self-sealing. But if you pull that nail out, you'll likely not get the next nail to seal as well, or at all, even if you use a bigger nail. You've compromised the vinyl where the screw penetrates, and subsequent screws are not sealing to the expanded or now-jagged hole in the vinyl. A good sealant should work, but that's not a guarantee, probably because the screw hole is now too messed up. The original screw won't work, for the same reasons. A bigger screw might seal, but you're right, it could crack the body. Or it might not seal, and you'll have cracked the body for nothing. So I'm not sure I'd try that.

I'm assuming a vinyl pool can be patched. If so, you shouldn't have to change the liner, though you might have to drain the pool. After removing the ring and gasket, a round patch could be applied to the existing liner, just slightly larger in diameter than the drain, then the upper gasket replaced with a new one, then the ring put back in place. The screws would then be going through new gasket and new liner. As long as the screws bite into the body, you should be good-to-go. Then they cut out the drain hole though the patch and install the drain cover. Something like that. If a vinyl pool can't be patched, then, uh, never mind...

I suppose the challenge will be draining the pool. I know vinyl pools don't like that. I'm not sure if any of what I described could be done with water in the pool. I would think that once the ring is removed, you'll have a deluge on your hands. Not sure you could work fast enough. Hopefully one of our experts will have a better fix.

This warning will come too late. The original installer is to blame, and should have been on the hook for the repair. But even if you can get a hold of him, he's now got a legitimate reason to deny a warranty repair because you messed with it, even if you didn't actually made it worse. A lesson learned for next time, perhaps. Still worth calling him though, ya never know.
 

Esand323

Well-known member
Aug 6, 2018
85
Indianapolis
Thanks for the reply!

It looks like the SPX1039Z18 is actually a #12 screw. I went to the hardware store and got a #12 screw that had a similar number of threads (stainless). I was actually able to cut it to length with a bolt cutter. I cut it to the same height as the ones that the installer used. So it's the same width as the "correct" ones, but slightly longer to match what the installer had.

It didn't seem stripped at all. In fact, it was catching real well and I got it real tight. However, the leak still did not stop. It's leaking about 1/4" to the right of the screw under the liner. I'm wondering if there might be a crack that I can't see. I did check the other screw that is to the right of the one that I replaced. It seemed tight and I didn't want to mess with it. I don't think the screw to the right would cause a leak under the one I was currently tightening, so I just left it alone.

Not sure why the screw is in tight, but there is still a leak. I think I might try to find a diver and see if they would dive in this cold temperatures and see if they can fix it somehow.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,892
Central California
There is a lot of force on the leak (the weight of the water), so there's that. And a leak can be elsewhere and follow an unobvious path to where it reveals itself, so there's that. So you might be trying to "fix" the wrong spot (or screw hole).

As I explained, just using the correct size screw isn't going to necessarily solve the leak, because the gaskets and sandwiched liner are now "used" and the holes are all bigger. Not by a lot, but when you consider the water pressure, it's enough.

And over-tightening can make it worse, as that will warp the seal and that can cause a leak. Even if you didn't over-tightening the last time, if you did previously that warping can still be there.
 

Esand323

Well-known member
Aug 6, 2018
85
Indianapolis
I'm pretty certain I know exactly where the leak is, only because the dye is making it very obvious. If I put the dye right by the that screw, all of the dye is getting pulled in pretty forcefully. It's not doing it anywhere else. It's the same as it was the last time I had to fix this leak.

If the screw I'm using now though is catching and I'm able to fully tighten it, wouldn't that mean it should be creating a good seal? The screw isn't loose at all now. I suppose though with the water pressure, even the smallest gap could still cause a leak, like you said. You're definitely right though, I need to be careful about over-tightening. I wouldn't rule out a crack at this point.

I think the biggest mistake I made was not cutting the excess liner out first. I did remove some of the excess liner, but I should have removed more. It would have given me a much better look. I took a screenshot of this video I saw on youtube. If the main drain pot looked like this without the excess liner, I'd probably be a bit more successful.

1.PNG



Even with the excess liner hanging over a bit, I put a bunch of "Permanent Sealer" around the entire area below the liner. Dye test seemed pretty promising. Going to continue to monitor the water level. Early indication is good, but need a bit more time.

I think I might just pay to get a diver out that knows what they are doing. I can't do much down there effectively without proper dive gear. I'd like to get the excess liner removed and see if we can get a better seal.


Thanks for the help!