Plumbing – Saddle valve keeps spinning

I think what is leaking is the drain. Does it look like the object sticking out to the side in the below picture? If so, this is used to drain water from the house side of the supply when the valve is off.

It sounds like you over tightened it in the first place which started the leaking. If you've broken only the cap, you might be able to find a replacement. If the stem and threads are damaged, long-term you will need to replace the entire valve. As a short-term fix, you just need to block it some how. Marine epoxy is handy for emergency plumbing repairs.

The proper name for it is a self piercing saddle valve. The valves are bad for many reasons, including the fact that they often clog and no longer allow water through the line, and they leak.

If you need a valve there to supply something like an ice maker or humidifier, then I'd cut the pipe, add a T, and put a proper quarter turn valve on the line.

To remove it, I'd just cut the pipe right on the piercing and install a copper coupling between the two cut pipes. The steps include: shutoff the water, remove the saddle valve (unscrew the two sides), cut the pipe, clean it, apply flux to the pipe and a copper coupling, fit them together, and solder the joint by heating with a blow torch and working solder into the joint from the opposite side. A skilled plumber should have the entire job done in under 30 minutes including setup and cleanup. For the DIY'er, you'll need the following tools and parts:

• Copper pipe cutter

• Fitting brush

• Flux and solder

• Blow torch

• Copper coupling

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