How to Rebuild a Shutoff Valve

Before starting, shut off the water supply at the main and open a faucet downstream to relieve pressure. Have a towel and small bucket handy—even with the water off, residual water in the line will seep out when you disassemble the valve stem. An adjustable wrench and screwdriver are all you need, but consider adding plumber’s grease to your materials list to lubricate the new packing and ensure a smooth, drip-free operation once reassembled.

Pro Tip: Rebuilding a shutoff valve is significantly less expensive than replacing the entire valve assembly, which often requires soldering or cutting into supply lines. A rebuild kit with replacement washers and packing material costs a fraction of a full valve replacement and can restore a leaky or stuck valve to like-new operation in under two hours.

Steps:

A shutoff valve has a stem that rises as you turn the handle, with a washer at the bottom that presses down against a part called the seat to hold water tight. If you see water dripping from the bottom of the stem, it suggests a problem with the washer or the seat. If water is leaking from the stem itself near the top, look at the bonnet—the nut that compresses a small gasket to create a seal.

1. Shut the water off to the house.
2. Pull the handle off the shutoff valve using the screwdriver.
3. Loosen the gland nut behind the handle using the wrench.
4. Unscrew and remove the valve.
5. Screw in the new valve from the repair kit.
6. Tighten the gland nut back over the new valve with the wrench.
7. Put the handle back on with the screwdriver.
8. Turn the water back on.

When you remove the bonnet nut and pull out the old valve stem, inspect the packing area carefully. In one This Old House project, the plumber found no gasket at all inside the bonnet—it had simply broken down over time. The fix was to wrap new Teflon packing around the spindle before reassembling, which restores the watertight seal around the stem.

Resources:
Richard repaired the stem on the kitchen faucet shutoff valve using a multi-turn valve stem repair kit, manufactured by BrassCraft.

Everything else he used to repair the shutoff valve, including the wrench and the screwdriver, can be purchased at home centers and plumbing supply stores.