Leak Between the Multi-Port and the Sand Filter


Jun 10, 2018
North Central PA
I've attempted to fix a leak at the gasket between my Hayward Vari-Flo XL valve and my Hayward S190TS High Rate sand filter. In removing the old gasket (which was replaced this spring when I deep cleaned the filter,) it was still in very good shape-no nicks, cracks, flat spots, etc. It is the blue Hayward Viton o-ring. At any rate, I had purchased a new gasket and installed it instead. Although the new one was black and not blue, it measured exactly the same as the old one, 7" inside diameter and 3/16" thick.

I used Jack's lube to lubricate the gasket and re-assembled everything. I followed the instructions and tapped lightly around the perimeter of the plastic clamp with a rubber mallet once it was lightly snugged down; supposed to help seat the new gasket. I fired up the system and the leak was still there. I took everything apart, wiped off the mating surfaces and tried again. Still leaking. I then got out my original blue gasket, repeated the above procedure, and had an even bigger leak. Took everything back apart and carefully inspected the bottom flange of the valve and the top flange of the tank for any small cracks. Nothing found.

The only thing I can see is that the 2-pc. plastic clamp is now touching on both sides when the clamp is tightened. There are no cracks in the clamp. Prior to today, there had always been about a 1/4" gap on each side of the clamp where the two pieces of the clamp joined. I always alternate with even turns on both bolts when assembling this connection. Is it possible the clamp has warped or weakened to allow it to be tightened this far? I have never been able to tighten it down this far before. Maybe I have caused a "bunching" of the gasket? If the clamp has just been over-tightened, what is the possibility that taking it apart, re-assembling it, and stop tightening the clamp while a gap is maintained, might alleviate the problem? Help! I'm running out of ideas. Thanks!


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Can you post pics of your MPV and the problem clamp and maybe someone with the same MPV can compare what they have versus yours?