Help with Leak on MAAX whirlpool tub

[axle]

I have a Maax whirlpool tub. It is new, but no warranty, so I'm trying to fix it myself. When I fill the tub, the union on top of the pump leaks. This connection is hand tightened. I have removed the O- ring several times and replaced it. I have added vaseline to the O- ring. I have loosened the pump from it's mounts to ensure the piping can be made up square. Nothing works. It leaks every time. The O- ring seems fine. The mating surface seems fine. Everything seems to go together as it should.

Does anyone have any idea as to what else I can try? I'm getting desparate. I'm thinking of trying to find a thicker o-ring. Or perhaps putting some gasket material from the automotive industry on the mating surface where the o-ring makes up.

There is another union on the suction side of the pump, and I have no problems with it. I can't see any difference between the two unions.

Help please!

Chris

[Steve]

Don't feel bad, a leak in the tub isn't bad. Just wait till someone pisses in your sink.

[salty]

Figure out what ther defect is. Are all the mating pieces perfectly round? Hold up something you know is round against them and check. Is there an undetected crack? They can be almost invisible unless you look very carefully under strong light. Any imperfections in the mating surfaces? A little indentation is all it takes.

If practical, just replace the involved parts.

[trader4]

Making sure the pump is loosened up enough to move was an excellent idea. I'd make sure it can move easily. Of course, it may later start to leak when you bolt the pump down so you might have to shim.

Next thing I'd try is to use a pair of pliars to tighten the union more than hand tight. Normally you only want it about hand tight, but in your case I would definitely go beyond hand tight, just don't over do it.

Since this spa has no warranty, is it possible it has unknown origin and the O ring might be the wrong one?

Also, as others have suggested, if you can just replace the union, that is another solution.

[axle]

I found the problem - there is a hair line crack. Thus, I need to replace the union. Thank you to everyone for the ideas. This one had me stumped. We tried different o-rings. Fatter ones. We even cut a gasket using gasket material. It was when we noticed that the gasket was only wet on the inside edges and not on the outside edges that we new the water wasn't leaking at this point. That is when we started looking for cracks. The "nut" covers the crack, so it is not visible from the outside. But if you stand on your head with a flash light, you can see inside far enough to see the crack.

Thank you, Chris

[hrhofmann]

Good to know that the problem is solved, assuming you can get a replacement part.