How to Replace a Spare Tire Valve Stem
What the spare tire valve stem does and when replacement is needed
A spare tire valve stem is the air inlet assembly mounted in the wheel. It includes the metal or rubber body, the valve core, and the sealing base that keeps air from escaping between the stem and the rim. The same basic component is used on full-size spares, compact temporary spares, and many trailer or utility wheels, but the exact stem type can vary by wheel design and material.
Replacement is generally required when the stem is cracked, cut, corroded, or leaking at its base. A leaking valve core can often be fixed by replacing only the core, but a cracked rubber stem or a damaged metal stem needs a complete valve stem replacement. Because the spare is unused for long periods, rubber stems can dry and crack even when the tread looks new.
Qualification: stem type depends on the wheel and spare
The replacement procedure is not identical for every spare. Rubber snap-in stems are common on steel spare wheels and are pulled through the rim hole from the inside. Bolt-in metal stems are used on some aluminum wheels and are secured with a nut and sealing washer. High-pressure temporary spares may use a specific stem rated for the spare’s inflation pressure. The owner’s manual or a parts listing for the exact wheel should be used to confirm the correct stem before starting.
Tools and supplies for the job
A basic replacement can be done with a valve core tool, a valve stem puller or installation tool, tire levers or a bead-breaking tool, a jack and support stands, a tire pressure gauge, and soapy water for leak testing. You will also need a new valve stem that matches the wheel hole diameter and type, plus a new valve core if the old core is being discarded.
Step-by-step replacement procedure
1) Remove the spare and release air
Take the spare tire off the vehicle and place it on a stable surface with the valve stem facing up. Remove the valve core with a valve core tool to release all remaining air. Do not attempt to break the bead or remove the stem while the tire is still inflated.
2) Break the bead near the valve stem
Press the tire sidewall down at the rim near the valve stem until the bead separates from the wheel. On many spare wheels this requires only firm pressure or a bead-breaking tool. The goal is to create enough room to reach the back of the valve stem inside the wheel. It is usually not necessary to remove the tire completely from the rim.
3) Remove the old valve stem
For a rubber snap-in stem, pull the old stem out through the inside of the rim. Cutting the old stem at its base can make removal easier if it is hardened. For a bolt-in metal stem, remove the retaining nut and washer from the outside, then pull the stem out from the inside. Clean the valve hole in the wheel and check it for corrosion or sharp edges.
4) Install the new valve stem
Lubricate the new rubber stem base with a mild soap solution and push it into the wheel from the inside. Use a valve stem puller to pull the stem through until its base seats evenly against the rim. For a bolt-in stem, insert it from the inside and secure the washer and nut to the specified torque, which is typically modest and should be confirmed for the wheel type.
5) Reinstall the valve core and inflate
Install a new valve core and tighten it gently with the valve core tool. Reseat the tire bead against the rim if it shifted, then inflate the spare to the pressure shown on the tire placard or spare label. Inflate gradually and keep hands clear of the bead area while the tire is seating.
Checking the repair
After inflation, apply soapy water around the base of the new valve stem and around the valve core opening. Bubbles indicate a leak that requires reseating the stem or tightening the core. Check the pressure again after a few minutes. If the spare is returned to storage under the vehicle or in a trunk, recheck its pressure periodically because spares lose air slowly even with a good valve stem.
When to use a tire shop instead
If the spare cannot be safely supported, the bead will not break with available tools, or the wheel uses a sensor-equipped stem, the repair may require professional tire equipment. Some spare wheels have tire pressure monitoring sensors attached to the stem, and those sensors can be damaged during stem replacement if the process is not handled correctly. Material uncertainty about the correct stem part number is also a reason to have the work done by a shop.