Replacing a valve stem is a relatively simple repair that most drivers can tackle themselves. The valve stem is the small tube that allows you to put air into your tire. It contains a valve that opens when you attach an air hose and allows air to enter the tire. Over time, valve stems can become damaged from wear and tear, resulting in a leak that causes the tire to lose air. While a professional mechanic can replace a valve stem, with a few basic tools and some patience, you can save money by learning how to do it yourself.
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What is a valve stem?
A valve stem is a small metal or rubber tube that is inserted through the rim of the wheel. One end extends just outside the rim and has a valve cap on top. This is where you attach an air hose to fill the tire with air. The other end of the valve stem extends inside the tire and has a valve mechanism inside. This valve opens when air pressure pushes on it from outside and closes when the air hose is removed to seal the tire and keep it inflated. There are two main types of valve stems:
- Rubber valve stems: These valve stems are made of rubber and typically found on older vehicles. They consist of the valve stem tube with a rubber grommet seal that fits into a metal hole in the wheel rim. While simple and inexpensive, rubber valve stems are prone to cracking and wear over time.
- Metal valve stems: These more modern valve stems are made of metal like aluminum or brass. They have a threaded base that screws into a threaded hole in the wheel rim for a tight seal. Metal valve stems are more durable than rubber and less prone to leaks.
Signs you may need to replace a valve stem
Here are some signs that indicate it may be time to replace your valve stem:
- You frequently need to refill a tire – If one tire keeps losing pressure rapidly, a damaged valve stem that leaks air could be the culprit.
- Visible cracks or damage – Look closely at the rubber on rubber valve stems and inspect for any cracking or damage which can allow leaks.
- Valve stem moves around – The valve stem should be securely seated in the wheel rim. If you can wiggle it around, the seal may be compromised.
- Air leaks when adding air – If you hear air hissing out around the valve stem as you try to inflate the tire, the valve stem needs replacement.
- Rust around metal valve stems – Rust indicates moisture has gotten in and damaged the valve seal, requiring a new valve stem.
Replacing a valve stem as soon as you notice signs of damage will allow you to fix the problem before a serious leak develops.
Tools and supplies needed
Replacing a valve stem is a quick job but you will need a few essential tools and supplies:
- Replacement valve stems – Available at any auto parts store, be sure to get the right type for your vehicle wheels.
- Valve stem tool – This special plier grips the valve stem tightly for easy removal and installation.
- Hex key or valve core tool – For removing the valve core from old stems prior to removal.
- Wheel blocks – To securely support the vehicle while you work on the valve stem.
- Tire gauge – To check your tire pressure before and after the repair.
- Torque wrench – For tightening the new valve stem securely to the wheel rim.
- Rags & cleaner – For wiping away grime around the wheel rim before installation.
Make sure you have all the tools and equipment you need before starting the valve stem replacement. The process will go much more smoothly with the right gear on hand.
Step-by-step instructions
Here are step-by-step instructions for replacing a valve stem yourself:
1. Remove tire from wheel
The first step is to remove the tire from the wheel so you can access the backside of the valve stem from inside the rim. Refer to your owner’s manual for proper jack placement and lug nut removal. Once the wheel is off, lay it flat to work on it.
2. Deflate tire completely
Use the tire valve to release all the air from the tire you’ll be working on. This makes it much easier to work the tire off the rim. Push on the tire sidewalls to help break the seal.
3. Remove valve core
Use a valve core removal tool to unscrew and remove the valve core located inside the valve stem. This releases any remaining air from inside the stem.
4. Remove old valve stem
Now use a valve stem removal tool to grip and twist the valve stem out of the wheel rim hole. For rubber stems, this plier tool grips the ribbed lower section. For metal stems, it fits around the hex base. Apply penetrating oil if needed to loosen a stuck stem.
5. Clean rim hole
Use a wire brush and rag to thoroughly clean the valve stem hole in the wheel. Remove any dirt, corrosion or old sealant. Proper cleaning ensures a good seal with the new stem.
6. Apply sealant to new valve stem
Lightly coat the threads and ribbed end of the new replacement valve stem with rubber sealant or Teflon tape. This ensures a leak-free seal when you install it.
7. Install new valve stem
Insert the new valve stem through the rim hole from the inside and hand tighten it until snug. Then use the valve stem tool to tighten it an additional 2-3 full turns or to the specified torque.
8. Install valve core
Screw the valve core back into the new valve stem. It only needs to be hand tight.
9. Remount tire
With the new valve stem in place, you can remount the tire onto the wheel. Make sure the tire beads seat evenly all around before inflating.
10. Inflate tire
Inflate the tire to the manufacturer’s recommended pressure. Then use soapy water to check around the new valve stem for any leaks.
Be sure to torque the lug nuts properly when reinstalling the wheel on your vehicle. Then you can hit the road knowing your tire’s new valve stem will provide many more miles of reliable service.
Tips for replacing valve stems
Follow these tips to make your DIY valve stem replacement go smoothly:
- Buy quality replacement valve stems specifically designed for your wheel type.
- Use the proper tools to avoid valve stem damage.
- Always deflate the tire fully before removing old valve stem.
- Make sure the rim hole is clean before inserting new valve stem.
- Apply sealant to the replacement valve stem for leak prevention.
- Tighten new valve stem with a torque wrench to the specified torque.
- Check for leaks and re-torque if needed to stop any seepage.
- Periodically inspect valve stems to get ahead of problems.
Conclusion
While valve stem replacement may sound complicated, it’s actually a straightforward repair you can easily master. With basic automotive tools, replacement valve stems, and the above step-by-step guide, you can replace a valve stem yourself in about 30 minutes or less. Paying close attention to proper cleaning, sealing, and torqueing techniques will ensure long-lasting results. So don’t hesitate to tackle this DIY repair and save the cost of paying a shop to do it.