Pour a dilute soap solution on the stem before beginning to determine if it's the source of the leak, and repair any leaks by replacing the valve stem core. The process takes about 10 minutes and requires a valve stem tool and replacement core.Continue Reading
The caps protect the stem from mud and dirt. Unscrew the cap, and save it to reinstall later.
Pour a small amount of dilute soapy water on the end of the valve stem. If it's leaking it should form bubbles.
Use the tapered end of the valve stem tool to remove any debris from the end of the valve stem so that they don't drop into the tire when you remove the stem insert.
Use the tool to unscrew the insert and remove it from the valve stem. Air leaks out of the stem when you loosen the insert. Work quickly so that the seal between the tire does not break.
Use the tool to screw the replacement part into the valve stem. Make sure it's snug, but do not over-tighten.
Use an air compressor to inflate the tire. Use a pressure gauge to check the pressure and ensure it's within the manufacturer's recommended range. Test for leaks.
Screw the cap back on the valve stem to provide protection as you drive the vehicle.