The house I bought a few years ago has a Proline frost-free sillcock that vibrates and rattles whenever water is flowing through it. I'm trying to figure out if it's serviceable. It has a removable gland nut and hex flats behind it on the main body that at first look like the bonnet, but up close they look like they are just cast into the main body, no threads are visible. If it is the bonnet, which I was initially 99% certain it was, it doesn't budge one bit, even with a 12" wrench. It seems like that's impossible, otherwise how could it have been assembled, but is it possible? The sillcock appears to be a cheap one, says made in Indonesia.



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That's an Ace hardware house brand of frostproof. The are cheaply made, but a repair kit is available for them, so the bonnet nut should unscrew. I'd replace it with a Woodford if possible.

Thanks for the info. Well, I spoke too soon when I wrote that post. I went back and was able to get the bonnet off. Interesting. There is nothing "broken" with the sillcock, but a lousy backflow preventer design is the root cause of all the noise. The spring that allows the washer to "float" along the stem allows for wobble, which the flow of water causes to happen rapidly, hence the noise. But functionally, it works.



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