Repair attempt of Grohe Quick Coupling

While in the middle of repairing the kitchen sink drain plumbing, I noticed a fairly significant leak under the sink.  OK, I’d failed to tighten one of the new plastic drain couplings in between repair sessions.  Fine.

But that didn’t fix most of it.  More observation found that it was coming from the source end of the flexible hose going to the faucet’s pull-out spray head.  Our Grohe LadyLux Plus faucet features a quick-connect (“Quick Coupling”) between the valve assembly and the hose to the spray.  This is a standard Grohe part, and for $30-40 I can get a replacement of the plastic end of the connection.  We have the yellow one (46 318000).  Installation is trivial.  And the leak is still small enough for a tray under the sink to catch it all.

I’m cheap, but not that cheap.  Send in a little money, get the part on the doorstep, 5 minutes work and Done.  I don’t have much problem with that.  Of course as several reviewers have commented, it’s pretty expensive for a plastic part.  And the part’s not damaged, and might be fixable.  It’s worth a try.  (So to be clear:  The motivation is maybe 20% cheap, and 80% “I can probably fix this.”)

The actual seal is an O-ring inside the plastic part.  It’s barely visible in the picture; feeling it with a probe was what convinced me of its existence.  (Just a guess, but that 25 cent part is probably all that’s needed in 90% of the repairs.)  It fits against the smooth outer surface of the male end coming from the valve.  A leak in a seal like that is often due to the crud and lime of the ages.  I’m a little surprised that no one mentions crud on the surface of the male part in discussions of repair by replacing the plastic part.

The repair plan

So the plan is to swab out the inside of the plastic part with Lime Away to get rid of the calcium deposits on the O-ring, clean the outside of the male part, and put ’em all back together with waterproof silicone grease.  Here we go.

Looking inside the plastic part, there was clearly some sort of device, but several commenters said the yellow (and green) versions don’t have a flow restrictor (though other colors do).  I vaguely recall that I might have removed a flow restrictor from the spray head end when it was all new, but I’m not sure.  And I could blow thru the plastic part both ways, so it obviously wasn’t a check valve.  But as I poked around with a Lime Away soaked Q-tip, that inside part seemed to move – and be spring loaded.  After some cleaning, it went from brown and crud-encrusted to pretty blue and white plastic parts.  And once cleaned out, it turned out to actually be a check valve!  A sensible (high end) feature – so the water in the hose doesn’t drain out when you disconnect the hose.  I rinsed it all out well, and called that done.

I scrubbed down the metal male part with a very well worn green scrubbie (couldn’t find a white one) soaked with Lime Away.  I tried to twist around the pipe rather than rubbing along its length, in case I introduced any scratches.  Unlikely, but…  It certainly looks cleaner, but the green ring of crud seems to remain.  I wonder where that hits with respect to the O-ring.

A significant part of the hope of helping it seal is a nice slathering of silicone grease.  Another Q-tip with that (on both surfaces), and it was ready to reassemble.  Done.

Fingers crossed – let’s see how it fares!  A couple of hours and a round of dish washing, and it’s still dry.  An update will follow.

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