hose bib sounds like a jack hammer

Had an old hose bib, leaked and made horrible noises. Cut into the wall, replaced with a brand new one from home depot, proper slope etc. Now it has the following problems: 1. if a hose with a sprayer is left on it (water on) water starts spurting out the handle of the bib. solved that by always turning off the water (not convenient but ok) 2. just hooked the hose to a sprinkler, and until the water was mostly on, it sounded like a jackhammer or a machine gun - awful, sounded like it was doing damage or would in the long term. what in the world is going on?? do i start over, did i get a bad one? is it a problem with the anti-siphon part? thanks Jim

The leak around the stem can be fixed by lubricating the stem and tightening up the stem packing nut.

The vibrating noise is probably a loose or damaged bibb washer on the stem, also easily fixed.

For what it's worth ( 2 cents!) bibbs should not normally be left on when not in use for any long period ( over 10 or 15 minutes.). The stem packing is not that rigoruous, and the hose itself also is not designed for that.

The valve you purchased from Depot has "spring type" backflow preventor that during backflow condition drains from the handle. When your hose is pressurized and the water pressure in your house drops (toilet flush, dishwasher, etc) the pressure in the hose is greater than the house, causes a backflow condition, and the excess backpressure in drained through the stem, out of a hole by the handle.

The jackhammering noise is during flow, the water pressure overcomes the spring pressure on the backflow preventor, then the spring jumps back...repeatedly, causing your noise.

Poorly designed import frostproof hydrant, next time look for a good domestic product without springs at a supply house.

thanks for the replies - the bib is a Mueller frost free (ten inch) with a red handle - made in tiawan. If that is a cheap one i will replace it -- have not finished the wall repair yet. if it is okay, i will repair the insides and be careful in the future . . .

NPMSTR said:

... next time look for a good domestic product without springs at a supply house.

Click to expand...

I just installed some Woodfords, as recommended by some of the folks here, and they are great. You can get them in a variety of lengths and configurations, and I got my three for a grand total of $40.00.

My own diagnosis is that the backflow preventor (white nylon, plus some O-rings and a washer) is not the source of the noise. There is no discharge from the backflow preventor during the noise. Now that I have opened up the American valve (from HD or Lowes, don't remember) I can see that the (nominal 12") stem is quite a complex device, which includes a spring loaded conical washer at the water control end, and a deliberately fragmented set of male threads (allmost 1/2" pipe size) through which the water flows) near the valve seat. There are also a sliding set of big rubber washers and a Bellville sort of steel washer that amount to the Bonnet Packing.

It was not easy to find a matching backflow rebuild kit. I rebuilt it myself. (I noticed that more than half of the frost-free faucets on sale at my HD had their backflow preventor stolen from the display.)

I don't blame American for the very hard water in my town. It looks like the original spring there (the moving part of the water valve) has broken, or become limed-up. $9 is not a bad price for the replacement part (which includes a pound of steel shaft.) But it does seem like a device that was designed to need maintenance. The 1955 sill cock I replaced lasted a lot longer.

Edit: And find a 3/8" 10-32 brass screw, in case the original breaks when you try to re-use the original handle.

Additional data: Because I could not remove the knob screw, I went to Lowes on 4/10/22 to buy an entire faucet. It turns out that the 12" American Valve unit has been completely redesigned between 2012 and 2022. The valve actuating threads are much coarser. As a result, the valve closes faster and feels like it may be less likely to be over-tightened. Luckily, the (solid steel) repair shaft that Amazon sent me (American Valve M72AS-STEM12) matched my "old" 2012 (plus or minus) valve.

Not only did they change the actuator thread, but to further discourage mis-use, they changed the (effective, if not actually) Bonnet Nut to a different diameter and thread, very close to the old size. So I'll have to saw off the old shaft to get the old bonnet nut.

The new (coarse actuator thread) model says "12in. M73AS", UPC 11918-11458. Made in Taiwan.