Mary couldn’t unscrew either of the two outlet hoses emerging from one of the (many) Y valves in her Vassar Farms plot. After deploying the Lesser Vise-Grip from my bike toolkit to no avail, I brought a Greater Vise-Grip from the shop and applied brute force. During that process, the plastic inlet hose fitting ripped off the valve and sprayed all but one of its latching teeth across the plot:
As it turns out, the male outlet hose fittings on all the metal-body Gilmour Y valves in the plot have corroded:
The scarred knurls show the force required to break the brass hose ring loose and unscrew it:
Some of that crud may be hard water deposits, but the destruction of the male threads seems like a galvanic reaction among all the various metals in play.
The male fitting began rotating in the valve body, so I crushed it in the bench vise to make more headway. While I had the victim clamped down, I hacksawed a slit through the housing, pried back the edges, and freed the parts for one leg of the Y:
You’d think “not corroding” would be high on the list of attributes for a garden hose valve…
The Smell of Molten Projects in the Morning 
“You’d think “not corroding” would be high on the list of attributes for a garden hose valve…”
It is. See:
http://www.essentialhardware.com/gilmour-17-nylon-y-connector-with-shut-off-182206.html?utm_campaign=google&utm_source=google&utm_medium=cpc&gclid=Cj0KEQiA39_BBRD0w-_rmOrc__8BEiQA-ETxXasLFW-XSAyF3aKXW-ZLPnsGDbT4wnIvrSfwr5Lp3IsaAleC8P8HAQ
Those have a smaller ball bore, so I use ’em further down the series of Y valves along the line. These hulking metal valves with full-flow bores seemed like a good idea at the time…
I’ve had a lot of Y valves go south, and finally made up a couple of my own. The Lesser uses 1/2″ ball valves, while the Greater uses 3/4″ ball valves. I drain them after each use (the mineral content of our water is impressive) and they’ve been good for several years.
The Greater manifold goes with the 3/4″ hoses that can be press-ganged into fire duty.
BTW, bringing up Slackware64 14.2 on a new Dell Inspiron. So far, so good, but I need a 32 bit library for the printer driver. Oh well.
There’s a four-valve manifold with full flow bores sitting just inside the garden gate, where it surely presents a tempting target for metal scavengers. The brass housing & stainless balls haven’t corroded, of course.